… | |
… | |
130 | .\} |
130 | .\} |
131 | .rm #[ #] #H #V #F C |
131 | .rm #[ #] #H #V #F C |
132 | .\" ======================================================================== |
132 | .\" ======================================================================== |
133 | .\" |
133 | .\" |
134 | .IX Title "LIBEV 3" |
134 | .IX Title "LIBEV 3" |
135 | .TH LIBEV 3 "2008-05-22" "libev-3.41" "libev - high perfromance full featured event loop" |
135 | .TH LIBEV 3 "2008-06-09" "libev-3.42" "libev - high performance full featured event loop" |
136 | .\" For nroff, turn off justification. Always turn off hyphenation; it makes |
136 | .\" For nroff, turn off justification. Always turn off hyphenation; it makes |
137 | .\" way too many mistakes in technical documents. |
137 | .\" way too many mistakes in technical documents. |
138 | .if n .ad l |
138 | .if n .ad l |
139 | .nh |
139 | .nh |
140 | .SH "NAME" |
140 | .SH "NAME" |
141 | libev \- a high performance full\-featured event loop written in C |
141 | libev \- a high performance full\-featured event loop written in C |
142 | .SH "SYNOPSIS" |
142 | .SH "SYNOPSIS" |
143 | .IX Header "SYNOPSIS" |
143 | .IX Header "SYNOPSIS" |
144 | .Vb 1 |
144 | .Vb 1 |
145 | \& #include <ev.h> |
145 | \& #include <ev.h> |
146 | .Ve |
146 | .Ve |
147 | .Sh "\s-1EXAMPLE\s0 \s-1PROGRAM\s0" |
147 | .Sh "\s-1EXAMPLE\s0 \s-1PROGRAM\s0" |
148 | .IX Subsection "EXAMPLE PROGRAM" |
148 | .IX Subsection "EXAMPLE PROGRAM" |
149 | .Vb 2 |
149 | .Vb 2 |
150 | \& // a single header file is required |
150 | \& // a single header file is required |
151 | \& #include <ev.h> |
151 | \& #include <ev.h> |
152 | \& |
152 | \& |
153 | \& // every watcher type has its own typedef\*(Aqd struct |
153 | \& // every watcher type has its own typedef\*(Aqd struct |
154 | \& // with the name ev_<type> |
154 | \& // with the name ev_<type> |
155 | \& ev_io stdin_watcher; |
155 | \& ev_io stdin_watcher; |
156 | \& ev_timer timeout_watcher; |
156 | \& ev_timer timeout_watcher; |
157 | \& |
157 | \& |
158 | \& // all watcher callbacks have a similar signature |
158 | \& // all watcher callbacks have a similar signature |
159 | \& // this callback is called when data is readable on stdin |
159 | \& // this callback is called when data is readable on stdin |
160 | \& static void |
160 | \& static void |
161 | \& stdin_cb (EV_P_ struct ev_io *w, int revents) |
161 | \& stdin_cb (EV_P_ struct ev_io *w, int revents) |
162 | \& { |
162 | \& { |
163 | \& puts ("stdin ready"); |
163 | \& puts ("stdin ready"); |
164 | \& // for one\-shot events, one must manually stop the watcher |
164 | \& // for one\-shot events, one must manually stop the watcher |
165 | \& // with its corresponding stop function. |
165 | \& // with its corresponding stop function. |
166 | \& ev_io_stop (EV_A_ w); |
166 | \& ev_io_stop (EV_A_ w); |
167 | \& |
167 | \& |
168 | \& // this causes all nested ev_loop\*(Aqs to stop iterating |
168 | \& // this causes all nested ev_loop\*(Aqs to stop iterating |
169 | \& ev_unloop (EV_A_ EVUNLOOP_ALL); |
169 | \& ev_unloop (EV_A_ EVUNLOOP_ALL); |
170 | \& } |
170 | \& } |
171 | \& |
171 | \& |
172 | \& // another callback, this time for a time\-out |
172 | \& // another callback, this time for a time\-out |
173 | \& static void |
173 | \& static void |
174 | \& timeout_cb (EV_P_ struct ev_timer *w, int revents) |
174 | \& timeout_cb (EV_P_ struct ev_timer *w, int revents) |
175 | \& { |
175 | \& { |
176 | \& puts ("timeout"); |
176 | \& puts ("timeout"); |
177 | \& // this causes the innermost ev_loop to stop iterating |
177 | \& // this causes the innermost ev_loop to stop iterating |
178 | \& ev_unloop (EV_A_ EVUNLOOP_ONE); |
178 | \& ev_unloop (EV_A_ EVUNLOOP_ONE); |
179 | \& } |
179 | \& } |
180 | \& |
180 | \& |
181 | \& int |
181 | \& int |
182 | \& main (void) |
182 | \& main (void) |
183 | \& { |
183 | \& { |
184 | \& // use the default event loop unless you have special needs |
184 | \& // use the default event loop unless you have special needs |
185 | \& struct ev_loop *loop = ev_default_loop (0); |
185 | \& struct ev_loop *loop = ev_default_loop (0); |
186 | \& |
186 | \& |
187 | \& // initialise an io watcher, then start it |
187 | \& // initialise an io watcher, then start it |
188 | \& // this one will watch for stdin to become readable |
188 | \& // this one will watch for stdin to become readable |
189 | \& ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ); |
189 | \& ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ); |
190 | \& ev_io_start (loop, &stdin_watcher); |
190 | \& ev_io_start (loop, &stdin_watcher); |
191 | \& |
191 | \& |
192 | \& // initialise a timer watcher, then start it |
192 | \& // initialise a timer watcher, then start it |
193 | \& // simple non\-repeating 5.5 second timeout |
193 | \& // simple non\-repeating 5.5 second timeout |
194 | \& ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.); |
194 | \& ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.); |
195 | \& ev_timer_start (loop, &timeout_watcher); |
195 | \& ev_timer_start (loop, &timeout_watcher); |
196 | \& |
196 | \& |
197 | \& // now wait for events to arrive |
197 | \& // now wait for events to arrive |
198 | \& ev_loop (loop, 0); |
198 | \& ev_loop (loop, 0); |
199 | \& |
199 | \& |
200 | \& // unloop was called, so exit |
200 | \& // unloop was called, so exit |
201 | \& return 0; |
201 | \& return 0; |
202 | \& } |
202 | \& } |
203 | .Ve |
203 | .Ve |
204 | .SH "DESCRIPTION" |
204 | .SH "DESCRIPTION" |
205 | .IX Header "DESCRIPTION" |
205 | .IX Header "DESCRIPTION" |
206 | The newest version of this document is also available as an html-formatted |
206 | The newest version of this document is also available as an html-formatted |
207 | web page you might find easier to navigate when reading it for the first |
207 | web page you might find easier to navigate when reading it for the first |
… | |
… | |
249 | Libev represents time as a single floating point number, representing the |
249 | Libev represents time as a single floating point number, representing the |
250 | (fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near |
250 | (fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere near |
251 | the beginning of 1970, details are complicated, don't ask). This type is |
251 | the beginning of 1970, details are complicated, don't ask). This type is |
252 | called \f(CW\*(C`ev_tstamp\*(C'\fR, which is what you should use too. It usually aliases |
252 | called \f(CW\*(C`ev_tstamp\*(C'\fR, which is what you should use too. It usually aliases |
253 | to the \f(CW\*(C`double\*(C'\fR type in C, and when you need to do any calculations on |
253 | to the \f(CW\*(C`double\*(C'\fR type in C, and when you need to do any calculations on |
254 | it, you should treat it as some floatingpoint value. Unlike the name |
254 | it, you should treat it as some floating point value. Unlike the name |
255 | component \f(CW\*(C`stamp\*(C'\fR might indicate, it is also used for time differences |
255 | component \f(CW\*(C`stamp\*(C'\fR might indicate, it is also used for time differences |
256 | throughout libev. |
256 | throughout libev. |
257 | .SH "ERROR HANDLING" |
257 | .SH "ERROR HANDLING" |
258 | .IX Header "ERROR HANDLING" |
258 | .IX Header "ERROR HANDLING" |
259 | Libev knows three classes of errors: operating system errors, usage errors |
259 | Libev knows three classes of errors: operating system errors, usage errors |
260 | and internal errors (bugs). |
260 | and internal errors (bugs). |
261 | .PP |
261 | .PP |
262 | When libev catches an operating system error it cannot handle (for example |
262 | When libev catches an operating system error it cannot handle (for example |
263 | a syscall indicating a condition libev cannot fix), it calls the callback |
263 | a system call indicating a condition libev cannot fix), it calls the callback |
264 | set via \f(CW\*(C`ev_set_syserr_cb\*(C'\fR, which is supposed to fix the problem or |
264 | set via \f(CW\*(C`ev_set_syserr_cb\*(C'\fR, which is supposed to fix the problem or |
265 | abort. The default is to print a diagnostic message and to call \f(CW\*(C`abort |
265 | abort. The default is to print a diagnostic message and to call \f(CW\*(C`abort |
266 | ()\*(C'\fR. |
266 | ()\*(C'\fR. |
267 | .PP |
267 | .PP |
268 | When libev detects a usage error such as a negative timer interval, then |
268 | When libev detects a usage error such as a negative timer interval, then |
… | |
… | |
284 | you actually want to know. |
284 | you actually want to know. |
285 | .IP "ev_sleep (ev_tstamp interval)" 4 |
285 | .IP "ev_sleep (ev_tstamp interval)" 4 |
286 | .IX Item "ev_sleep (ev_tstamp interval)" |
286 | .IX Item "ev_sleep (ev_tstamp interval)" |
287 | Sleep for the given interval: The current thread will be blocked until |
287 | Sleep for the given interval: The current thread will be blocked until |
288 | either it is interrupted or the given time interval has passed. Basically |
288 | either it is interrupted or the given time interval has passed. Basically |
289 | this is a subsecond-resolution \f(CW\*(C`sleep ()\*(C'\fR. |
289 | this is a sub-second-resolution \f(CW\*(C`sleep ()\*(C'\fR. |
290 | .IP "int ev_version_major ()" 4 |
290 | .IP "int ev_version_major ()" 4 |
291 | .IX Item "int ev_version_major ()" |
291 | .IX Item "int ev_version_major ()" |
292 | .PD 0 |
292 | .PD 0 |
293 | .IP "int ev_version_minor ()" 4 |
293 | .IP "int ev_version_minor ()" 4 |
294 | .IX Item "int ev_version_minor ()" |
294 | .IX Item "int ev_version_minor ()" |
… | |
… | |
309 | .Sp |
309 | .Sp |
310 | Example: Make sure we haven't accidentally been linked against the wrong |
310 | Example: Make sure we haven't accidentally been linked against the wrong |
311 | version. |
311 | version. |
312 | .Sp |
312 | .Sp |
313 | .Vb 3 |
313 | .Vb 3 |
314 | \& assert (("libev version mismatch", |
314 | \& assert (("libev version mismatch", |
315 | \& ev_version_major () == EV_VERSION_MAJOR |
315 | \& ev_version_major () == EV_VERSION_MAJOR |
316 | \& && ev_version_minor () >= EV_VERSION_MINOR)); |
316 | \& && ev_version_minor () >= EV_VERSION_MINOR)); |
317 | .Ve |
317 | .Ve |
318 | .IP "unsigned int ev_supported_backends ()" 4 |
318 | .IP "unsigned int ev_supported_backends ()" 4 |
319 | .IX Item "unsigned int ev_supported_backends ()" |
319 | .IX Item "unsigned int ev_supported_backends ()" |
320 | Return the set of all backends (i.e. their corresponding \f(CW\*(C`EV_BACKEND_*\*(C'\fR |
320 | Return the set of all backends (i.e. their corresponding \f(CW\*(C`EV_BACKEND_*\*(C'\fR |
321 | value) compiled into this binary of libev (independent of their |
321 | value) compiled into this binary of libev (independent of their |
… | |
… | |
324 | .Sp |
324 | .Sp |
325 | Example: make sure we have the epoll method, because yeah this is cool and |
325 | Example: make sure we have the epoll method, because yeah this is cool and |
326 | a must have and can we have a torrent of it please!!!11 |
326 | a must have and can we have a torrent of it please!!!11 |
327 | .Sp |
327 | .Sp |
328 | .Vb 2 |
328 | .Vb 2 |
329 | \& assert (("sorry, no epoll, no sex", |
329 | \& assert (("sorry, no epoll, no sex", |
330 | \& ev_supported_backends () & EVBACKEND_EPOLL)); |
330 | \& ev_supported_backends () & EVBACKEND_EPOLL)); |
331 | .Ve |
331 | .Ve |
332 | .IP "unsigned int ev_recommended_backends ()" 4 |
332 | .IP "unsigned int ev_recommended_backends ()" 4 |
333 | .IX Item "unsigned int ev_recommended_backends ()" |
333 | .IX Item "unsigned int ev_recommended_backends ()" |
334 | Return the set of all backends compiled into this binary of libev and also |
334 | Return the set of all backends compiled into this binary of libev and also |
335 | recommended for this platform. This set is often smaller than the one |
335 | recommended for this platform. This set is often smaller than the one |
336 | returned by \f(CW\*(C`ev_supported_backends\*(C'\fR, as for example kqueue is broken on |
336 | returned by \f(CW\*(C`ev_supported_backends\*(C'\fR, as for example kqueue is broken on |
337 | most BSDs and will not be autodetected unless you explicitly request it |
337 | most BSDs and will not be auto-detected unless you explicitly request it |
338 | (assuming you know what you are doing). This is the set of backends that |
338 | (assuming you know what you are doing). This is the set of backends that |
339 | libev will probe for if you specify no backends explicitly. |
339 | libev will probe for if you specify no backends explicitly. |
340 | .IP "unsigned int ev_embeddable_backends ()" 4 |
340 | .IP "unsigned int ev_embeddable_backends ()" 4 |
341 | .IX Item "unsigned int ev_embeddable_backends ()" |
341 | .IX Item "unsigned int ev_embeddable_backends ()" |
342 | Returns the set of backends that are embeddable in other event loops. This |
342 | Returns the set of backends that are embeddable in other event loops. This |
… | |
… | |
383 | \& ... |
383 | \& ... |
384 | \& ev_set_allocator (persistent_realloc); |
384 | \& ev_set_allocator (persistent_realloc); |
385 | .Ve |
385 | .Ve |
386 | .IP "ev_set_syserr_cb (void (*cb)(const char *msg));" 4 |
386 | .IP "ev_set_syserr_cb (void (*cb)(const char *msg));" 4 |
387 | .IX Item "ev_set_syserr_cb (void (*cb)(const char *msg));" |
387 | .IX Item "ev_set_syserr_cb (void (*cb)(const char *msg));" |
388 | Set the callback function to call on a retryable syscall error (such |
388 | Set the callback function to call on a retryable system call error (such |
389 | as failed select, poll, epoll_wait). The message is a printable string |
389 | as failed select, poll, epoll_wait). The message is a printable string |
390 | indicating the system call or subsystem causing the problem. If this |
390 | indicating the system call or subsystem causing the problem. If this |
391 | callback is set, then libev will expect it to remedy the sitution, no |
391 | callback is set, then libev will expect it to remedy the situation, no |
392 | matter what, when it returns. That is, libev will generally retry the |
392 | matter what, when it returns. That is, libev will generally retry the |
393 | requested operation, or, if the condition doesn't go away, do bad stuff |
393 | requested operation, or, if the condition doesn't go away, do bad stuff |
394 | (such as abort). |
394 | (such as abort). |
395 | .Sp |
395 | .Sp |
396 | Example: This is basically the same thing that libev does internally, too. |
396 | Example: This is basically the same thing that libev does internally, too. |
… | |
… | |
425 | from multiple threads, you have to lock (note also that this is unlikely, |
425 | from multiple threads, you have to lock (note also that this is unlikely, |
426 | as loops cannot bes hared easily between threads anyway). |
426 | as loops cannot bes hared easily between threads anyway). |
427 | .Sp |
427 | .Sp |
428 | The default loop is the only loop that can handle \f(CW\*(C`ev_signal\*(C'\fR and |
428 | The default loop is the only loop that can handle \f(CW\*(C`ev_signal\*(C'\fR and |
429 | \&\f(CW\*(C`ev_child\*(C'\fR watchers, and to do this, it always registers a handler |
429 | \&\f(CW\*(C`ev_child\*(C'\fR watchers, and to do this, it always registers a handler |
430 | for \f(CW\*(C`SIGCHLD\*(C'\fR. If this is a problem for your app you can either |
430 | for \f(CW\*(C`SIGCHLD\*(C'\fR. If this is a problem for your application you can either |
431 | create a dynamic loop with \f(CW\*(C`ev_loop_new\*(C'\fR that doesn't do that, or you |
431 | create a dynamic loop with \f(CW\*(C`ev_loop_new\*(C'\fR that doesn't do that, or you |
432 | can simply overwrite the \f(CW\*(C`SIGCHLD\*(C'\fR signal handler \fIafter\fR calling |
432 | can simply overwrite the \f(CW\*(C`SIGCHLD\*(C'\fR signal handler \fIafter\fR calling |
433 | \&\f(CW\*(C`ev_default_init\*(C'\fR. |
433 | \&\f(CW\*(C`ev_default_init\*(C'\fR. |
434 | .Sp |
434 | .Sp |
435 | The flags argument can be used to specify special behaviour or specific |
435 | The flags argument can be used to specify special behaviour or specific |
… | |
… | |
443 | The default flags value. Use this if you have no clue (it's the right |
443 | The default flags value. Use this if you have no clue (it's the right |
444 | thing, believe me). |
444 | thing, believe me). |
445 | .ie n .IP """EVFLAG_NOENV""" 4 |
445 | .ie n .IP """EVFLAG_NOENV""" 4 |
446 | .el .IP "\f(CWEVFLAG_NOENV\fR" 4 |
446 | .el .IP "\f(CWEVFLAG_NOENV\fR" 4 |
447 | .IX Item "EVFLAG_NOENV" |
447 | .IX Item "EVFLAG_NOENV" |
448 | If this flag bit is ored into the flag value (or the program runs setuid |
448 | If this flag bit is or'ed into the flag value (or the program runs setuid |
449 | or setgid) then libev will \fInot\fR look at the environment variable |
449 | or setgid) then libev will \fInot\fR look at the environment variable |
450 | \&\f(CW\*(C`LIBEV_FLAGS\*(C'\fR. Otherwise (the default), this environment variable will |
450 | \&\f(CW\*(C`LIBEV_FLAGS\*(C'\fR. Otherwise (the default), this environment variable will |
451 | override the flags completely if it is found in the environment. This is |
451 | override the flags completely if it is found in the environment. This is |
452 | useful to try out specific backends to test their performance, or to work |
452 | useful to try out specific backends to test their performance, or to work |
453 | around bugs. |
453 | around bugs. |
… | |
… | |
460 | .Sp |
460 | .Sp |
461 | This works by calling \f(CW\*(C`getpid ()\*(C'\fR on every iteration of the loop, |
461 | This works by calling \f(CW\*(C`getpid ()\*(C'\fR on every iteration of the loop, |
462 | and thus this might slow down your event loop if you do a lot of loop |
462 | and thus this might slow down your event loop if you do a lot of loop |
463 | iterations and little real work, but is usually not noticeable (on my |
463 | iterations and little real work, but is usually not noticeable (on my |
464 | GNU/Linux system for example, \f(CW\*(C`getpid\*(C'\fR is actually a simple 5\-insn sequence |
464 | GNU/Linux system for example, \f(CW\*(C`getpid\*(C'\fR is actually a simple 5\-insn sequence |
465 | without a syscall and thus \fIvery\fR fast, but my GNU/Linux system also has |
465 | without a system call and thus \fIvery\fR fast, but my GNU/Linux system also has |
466 | \&\f(CW\*(C`pthread_atfork\*(C'\fR which is even faster). |
466 | \&\f(CW\*(C`pthread_atfork\*(C'\fR which is even faster). |
467 | .Sp |
467 | .Sp |
468 | The big advantage of this flag is that you can forget about fork (and |
468 | The big advantage of this flag is that you can forget about fork (and |
469 | forget about forgetting to tell libev about forking) when you use this |
469 | forget about forgetting to tell libev about forking) when you use this |
470 | flag. |
470 | flag. |
471 | .Sp |
471 | .Sp |
472 | This flag setting cannot be overriden or specified in the \f(CW\*(C`LIBEV_FLAGS\*(C'\fR |
472 | This flag setting cannot be overridden or specified in the \f(CW\*(C`LIBEV_FLAGS\*(C'\fR |
473 | environment variable. |
473 | environment variable. |
474 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
474 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
475 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
475 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
476 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
476 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
477 | This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
477 | This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
… | |
… | |
479 | but if that fails, expect a fairly low limit on the number of fds when |
479 | but if that fails, expect a fairly low limit on the number of fds when |
480 | using this backend. It doesn't scale too well (O(highest_fd)), but its |
480 | using this backend. It doesn't scale too well (O(highest_fd)), but its |
481 | usually the fastest backend for a low number of (low-numbered :) fds. |
481 | usually the fastest backend for a low number of (low-numbered :) fds. |
482 | .Sp |
482 | .Sp |
483 | To get good performance out of this backend you need a high amount of |
483 | To get good performance out of this backend you need a high amount of |
484 | parallelity (most of the file descriptors should be busy). If you are |
484 | parallelism (most of the file descriptors should be busy). If you are |
485 | writing a server, you should \f(CW\*(C`accept ()\*(C'\fR in a loop to accept as many |
485 | writing a server, you should \f(CW\*(C`accept ()\*(C'\fR in a loop to accept as many |
486 | connections as possible during one iteration. You might also want to have |
486 | connections as possible during one iteration. You might also want to have |
487 | a look at \f(CW\*(C`ev_set_io_collect_interval ()\*(C'\fR to increase the amount of |
487 | a look at \f(CW\*(C`ev_set_io_collect_interval ()\*(C'\fR to increase the amount of |
488 | readiness notifications you get per iteration. |
488 | readiness notifications you get per iteration. |
489 | .ie n .IP """EVBACKEND_POLL"" (value 2, poll backend, available everywhere except on windows)" 4 |
489 | .ie n .IP """EVBACKEND_POLL"" (value 2, poll backend, available everywhere except on windows)" 4 |
… | |
… | |
501 | For few fds, this backend is a bit little slower than poll and select, |
501 | For few fds, this backend is a bit little slower than poll and select, |
502 | but it scales phenomenally better. While poll and select usually scale |
502 | but it scales phenomenally better. While poll and select usually scale |
503 | like O(total_fds) where n is the total number of fds (or the highest fd), |
503 | like O(total_fds) where n is the total number of fds (or the highest fd), |
504 | epoll scales either O(1) or O(active_fds). The epoll design has a number |
504 | epoll scales either O(1) or O(active_fds). The epoll design has a number |
505 | of shortcomings, such as silently dropping events in some hard-to-detect |
505 | of shortcomings, such as silently dropping events in some hard-to-detect |
506 | cases and requiring a syscall per fd change, no fork support and bad |
506 | cases and requiring a system call per fd change, no fork support and bad |
507 | support for dup. |
507 | support for dup. |
508 | .Sp |
508 | .Sp |
509 | While stopping, setting and starting an I/O watcher in the same iteration |
509 | While stopping, setting and starting an I/O watcher in the same iteration |
510 | will result in some caching, there is still a syscall per such incident |
510 | will result in some caching, there is still a system call per such incident |
511 | (because the fd could point to a different file description now), so its |
511 | (because the fd could point to a different file description now), so its |
512 | best to avoid that. Also, \f(CW\*(C`dup ()\*(C'\fR'ed file descriptors might not work |
512 | best to avoid that. Also, \f(CW\*(C`dup ()\*(C'\fR'ed file descriptors might not work |
513 | very well if you register events for both fds. |
513 | very well if you register events for both fds. |
514 | .Sp |
514 | .Sp |
515 | Please note that epoll sometimes generates spurious notifications, so you |
515 | Please note that epoll sometimes generates spurious notifications, so you |
… | |
… | |
518 | .Sp |
518 | .Sp |
519 | Best performance from this backend is achieved by not unregistering all |
519 | Best performance from this backend is achieved by not unregistering all |
520 | watchers for a file descriptor until it has been closed, if possible, i.e. |
520 | watchers for a file descriptor until it has been closed, if possible, i.e. |
521 | keep at least one watcher active per fd at all times. |
521 | keep at least one watcher active per fd at all times. |
522 | .Sp |
522 | .Sp |
523 | While nominally embeddeble in other event loops, this feature is broken in |
523 | While nominally embeddable in other event loops, this feature is broken in |
524 | all kernel versions tested so far. |
524 | all kernel versions tested so far. |
525 | .ie n .IP """EVBACKEND_KQUEUE"" (value 8, most \s-1BSD\s0 clones)" 4 |
525 | .ie n .IP """EVBACKEND_KQUEUE"" (value 8, most \s-1BSD\s0 clones)" 4 |
526 | .el .IP "\f(CWEVBACKEND_KQUEUE\fR (value 8, most \s-1BSD\s0 clones)" 4 |
526 | .el .IP "\f(CWEVBACKEND_KQUEUE\fR (value 8, most \s-1BSD\s0 clones)" 4 |
527 | .IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)" |
527 | .IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)" |
528 | Kqueue deserves special mention, as at the time of this writing, it |
528 | Kqueue deserves special mention, as at the time of this writing, it |
529 | was broken on all BSDs except NetBSD (usually it doesn't work reliably |
529 | was broken on all BSDs except NetBSD (usually it doesn't work reliably |
530 | with anything but sockets and pipes, except on Darwin, where of course |
530 | with anything but sockets and pipes, except on Darwin, where of course |
531 | it's completely useless). For this reason it's not being \*(L"autodetected\*(R" |
531 | it's completely useless). For this reason it's not being \*(L"auto-detected\*(R" |
532 | unless you explicitly specify it explicitly in the flags (i.e. using |
532 | unless you explicitly specify it explicitly in the flags (i.e. using |
533 | \&\f(CW\*(C`EVBACKEND_KQUEUE\*(C'\fR) or libev was compiled on a known-to-be-good (\-enough) |
533 | \&\f(CW\*(C`EVBACKEND_KQUEUE\*(C'\fR) or libev was compiled on a known-to-be-good (\-enough) |
534 | system like NetBSD. |
534 | system like NetBSD. |
535 | .Sp |
535 | .Sp |
536 | You still can embed kqueue into a normal poll or select backend and use it |
536 | You still can embed kqueue into a normal poll or select backend and use it |
… | |
… | |
538 | the target platform). See \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
538 | the target platform). See \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
539 | .Sp |
539 | .Sp |
540 | It scales in the same way as the epoll backend, but the interface to the |
540 | It scales in the same way as the epoll backend, but the interface to the |
541 | kernel is more efficient (which says nothing about its actual speed, of |
541 | kernel is more efficient (which says nothing about its actual speed, of |
542 | course). While stopping, setting and starting an I/O watcher does never |
542 | course). While stopping, setting and starting an I/O watcher does never |
543 | cause an extra syscall as with \f(CW\*(C`EVBACKEND_EPOLL\*(C'\fR, it still adds up to |
543 | cause an extra system call as with \f(CW\*(C`EVBACKEND_EPOLL\*(C'\fR, it still adds up to |
544 | two event changes per incident, support for \f(CW\*(C`fork ()\*(C'\fR is very bad and it |
544 | two event changes per incident, support for \f(CW\*(C`fork ()\*(C'\fR is very bad and it |
545 | drops fds silently in similarly hard-to-detect cases. |
545 | drops fds silently in similarly hard-to-detect cases. |
546 | .Sp |
546 | .Sp |
547 | This backend usually performs well under most conditions. |
547 | This backend usually performs well under most conditions. |
548 | .Sp |
548 | .Sp |
… | |
… | |
563 | .el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4 |
563 | .el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4 |
564 | .IX Item "EVBACKEND_PORT (value 32, Solaris 10)" |
564 | .IX Item "EVBACKEND_PORT (value 32, Solaris 10)" |
565 | This uses the Solaris 10 event port mechanism. As with everything on Solaris, |
565 | This uses the Solaris 10 event port mechanism. As with everything on Solaris, |
566 | it's really slow, but it still scales very well (O(active_fds)). |
566 | it's really slow, but it still scales very well (O(active_fds)). |
567 | .Sp |
567 | .Sp |
568 | Please note that solaris event ports can deliver a lot of spurious |
568 | Please note that Solaris event ports can deliver a lot of spurious |
569 | notifications, so you need to use non-blocking I/O or other means to avoid |
569 | notifications, so you need to use non-blocking I/O or other means to avoid |
570 | blocking when no data (or space) is available. |
570 | blocking when no data (or space) is available. |
571 | .Sp |
571 | .Sp |
572 | While this backend scales well, it requires one system call per active |
572 | While this backend scales well, it requires one system call per active |
573 | file descriptor per loop iteration. For small and medium numbers of file |
573 | file descriptor per loop iteration. For small and medium numbers of file |
… | |
… | |
586 | .Sp |
586 | .Sp |
587 | It is definitely not recommended to use this flag. |
587 | It is definitely not recommended to use this flag. |
588 | .RE |
588 | .RE |
589 | .RS 4 |
589 | .RS 4 |
590 | .Sp |
590 | .Sp |
591 | If one or more of these are ored into the flags value, then only these |
591 | If one or more of these are or'ed into the flags value, then only these |
592 | backends will be tried (in the reverse order as listed here). If none are |
592 | backends will be tried (in the reverse order as listed here). If none are |
593 | specified, all backends in \f(CW\*(C`ev_recommended_backends ()\*(C'\fR will be tried. |
593 | specified, all backends in \f(CW\*(C`ev_recommended_backends ()\*(C'\fR will be tried. |
594 | .Sp |
594 | .Sp |
595 | The most typical usage is like this: |
595 | The most typical usage is like this: |
596 | .Sp |
596 | .Sp |
597 | .Vb 2 |
597 | .Vb 2 |
598 | \& if (!ev_default_loop (0)) |
598 | \& if (!ev_default_loop (0)) |
599 | \& fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?"); |
599 | \& fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?"); |
600 | .Ve |
600 | .Ve |
601 | .Sp |
601 | .Sp |
602 | Restrict libev to the select and poll backends, and do not allow |
602 | Restrict libev to the select and poll backends, and do not allow |
603 | environment settings to be taken into account: |
603 | environment settings to be taken into account: |
604 | .Sp |
604 | .Sp |
605 | .Vb 1 |
605 | .Vb 1 |
606 | \& ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV); |
606 | \& ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV); |
607 | .Ve |
607 | .Ve |
608 | .Sp |
608 | .Sp |
609 | Use whatever libev has to offer, but make sure that kqueue is used if |
609 | Use whatever libev has to offer, but make sure that kqueue is used if |
610 | available (warning, breaks stuff, best use only with your own private |
610 | available (warning, breaks stuff, best use only with your own private |
611 | event loop and only if you know the \s-1OS\s0 supports your types of fds): |
611 | event loop and only if you know the \s-1OS\s0 supports your types of fds): |
612 | .Sp |
612 | .Sp |
613 | .Vb 1 |
613 | .Vb 1 |
614 | \& ev_default_loop (ev_recommended_backends () | EVBACKEND_KQUEUE); |
614 | \& ev_default_loop (ev_recommended_backends () | EVBACKEND_KQUEUE); |
615 | .Ve |
615 | .Ve |
616 | .RE |
616 | .RE |
617 | .IP "struct ev_loop *ev_loop_new (unsigned int flags)" 4 |
617 | .IP "struct ev_loop *ev_loop_new (unsigned int flags)" 4 |
618 | .IX Item "struct ev_loop *ev_loop_new (unsigned int flags)" |
618 | .IX Item "struct ev_loop *ev_loop_new (unsigned int flags)" |
619 | Similar to \f(CW\*(C`ev_default_loop\*(C'\fR, but always creates a new event loop that is |
619 | Similar to \f(CW\*(C`ev_default_loop\*(C'\fR, but always creates a new event loop that is |
… | |
… | |
626 | default loop in the \*(L"main\*(R" or \*(L"initial\*(R" thread. |
626 | default loop in the \*(L"main\*(R" or \*(L"initial\*(R" thread. |
627 | .Sp |
627 | .Sp |
628 | Example: Try to create a event loop that uses epoll and nothing else. |
628 | Example: Try to create a event loop that uses epoll and nothing else. |
629 | .Sp |
629 | .Sp |
630 | .Vb 3 |
630 | .Vb 3 |
631 | \& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
631 | \& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
632 | \& if (!epoller) |
632 | \& if (!epoller) |
633 | \& fatal ("no epoll found here, maybe it hides under your chair"); |
633 | \& fatal ("no epoll found here, maybe it hides under your chair"); |
634 | .Ve |
634 | .Ve |
635 | .IP "ev_default_destroy ()" 4 |
635 | .IP "ev_default_destroy ()" 4 |
636 | .IX Item "ev_default_destroy ()" |
636 | .IX Item "ev_default_destroy ()" |
637 | Destroys the default loop again (frees all memory and kernel state |
637 | Destroys the default loop again (frees all memory and kernel state |
638 | etc.). None of the active event watchers will be stopped in the normal |
638 | etc.). None of the active event watchers will be stopped in the normal |
639 | sense, so e.g. \f(CW\*(C`ev_is_active\*(C'\fR might still return true. It is your |
639 | sense, so e.g. \f(CW\*(C`ev_is_active\*(C'\fR might still return true. It is your |
640 | responsibility to either stop all watchers cleanly yoursef \fIbefore\fR |
640 | responsibility to either stop all watchers cleanly yourself \fIbefore\fR |
641 | calling this function, or cope with the fact afterwards (which is usually |
641 | calling this function, or cope with the fact afterwards (which is usually |
642 | the easiest thing, you can just ignore the watchers and/or \f(CW\*(C`free ()\*(C'\fR them |
642 | the easiest thing, you can just ignore the watchers and/or \f(CW\*(C`free ()\*(C'\fR them |
643 | for example). |
643 | for example). |
644 | .Sp |
644 | .Sp |
645 | Note that certain global state, such as signal state, will not be freed by |
645 | Note that certain global state, such as signal state, will not be freed by |
… | |
… | |
720 | A flags value of \f(CW\*(C`EVLOOP_NONBLOCK\*(C'\fR will look for new events, will handle |
720 | A flags value of \f(CW\*(C`EVLOOP_NONBLOCK\*(C'\fR will look for new events, will handle |
721 | those events and any outstanding ones, but will not block your process in |
721 | those events and any outstanding ones, but will not block your process in |
722 | case there are no events and will return after one iteration of the loop. |
722 | case there are no events and will return after one iteration of the loop. |
723 | .Sp |
723 | .Sp |
724 | A flags value of \f(CW\*(C`EVLOOP_ONESHOT\*(C'\fR will look for new events (waiting if |
724 | A flags value of \f(CW\*(C`EVLOOP_ONESHOT\*(C'\fR will look for new events (waiting if |
725 | neccessary) and will handle those and any outstanding ones. It will block |
725 | necessary) and will handle those and any outstanding ones. It will block |
726 | your process until at least one new event arrives, and will return after |
726 | your process until at least one new event arrives, and will return after |
727 | one iteration of the loop. This is useful if you are waiting for some |
727 | one iteration of the loop. This is useful if you are waiting for some |
728 | external event in conjunction with something not expressible using other |
728 | external event in conjunction with something not expressible using other |
729 | libev watchers. However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is |
729 | libev watchers. However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is |
730 | usually a better approach for this kind of thing. |
730 | usually a better approach for this kind of thing. |
… | |
… | |
796 | .Sp |
796 | .Sp |
797 | Example: Create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR |
797 | Example: Create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR |
798 | running when nothing else is active. |
798 | running when nothing else is active. |
799 | .Sp |
799 | .Sp |
800 | .Vb 4 |
800 | .Vb 4 |
801 | \& struct ev_signal exitsig; |
801 | \& struct ev_signal exitsig; |
802 | \& ev_signal_init (&exitsig, sig_cb, SIGINT); |
802 | \& ev_signal_init (&exitsig, sig_cb, SIGINT); |
803 | \& ev_signal_start (loop, &exitsig); |
803 | \& ev_signal_start (loop, &exitsig); |
804 | \& evf_unref (loop); |
804 | \& evf_unref (loop); |
805 | .Ve |
805 | .Ve |
806 | .Sp |
806 | .Sp |
807 | Example: For some weird reason, unregister the above signal handler again. |
807 | Example: For some weird reason, unregister the above signal handler again. |
808 | .Sp |
808 | .Sp |
809 | .Vb 2 |
809 | .Vb 2 |
810 | \& ev_ref (loop); |
810 | \& ev_ref (loop); |
811 | \& ev_signal_stop (loop, &exitsig); |
811 | \& ev_signal_stop (loop, &exitsig); |
812 | .Ve |
812 | .Ve |
813 | .IP "ev_set_io_collect_interval (loop, ev_tstamp interval)" 4 |
813 | .IP "ev_set_io_collect_interval (loop, ev_tstamp interval)" 4 |
814 | .IX Item "ev_set_io_collect_interval (loop, ev_tstamp interval)" |
814 | .IX Item "ev_set_io_collect_interval (loop, ev_tstamp interval)" |
815 | .PD 0 |
815 | .PD 0 |
816 | .IP "ev_set_timeout_collect_interval (loop, ev_tstamp interval)" 4 |
816 | .IP "ev_set_timeout_collect_interval (loop, ev_tstamp interval)" 4 |
… | |
… | |
840 | to spend more time collecting timeouts, at the expense of increased |
840 | to spend more time collecting timeouts, at the expense of increased |
841 | latency (the watcher callback will be called later). \f(CW\*(C`ev_io\*(C'\fR watchers |
841 | latency (the watcher callback will be called later). \f(CW\*(C`ev_io\*(C'\fR watchers |
842 | will not be affected. Setting this to a non-null value will not introduce |
842 | will not be affected. Setting this to a non-null value will not introduce |
843 | any overhead in libev. |
843 | any overhead in libev. |
844 | .Sp |
844 | .Sp |
845 | Many (busy) programs can usually benefit by setting the io collect |
845 | Many (busy) programs can usually benefit by setting the I/O collect |
846 | interval to a value near \f(CW0.1\fR or so, which is often enough for |
846 | interval to a value near \f(CW0.1\fR or so, which is often enough for |
847 | interactive servers (of course not for games), likewise for timeouts. It |
847 | interactive servers (of course not for games), likewise for timeouts. It |
848 | usually doesn't make much sense to set it to a lower value than \f(CW0.01\fR, |
848 | usually doesn't make much sense to set it to a lower value than \f(CW0.01\fR, |
849 | as this approsaches the timing granularity of most systems. |
849 | as this approaches the timing granularity of most systems. |
850 | .IP "ev_loop_verify (loop)" 4 |
850 | .IP "ev_loop_verify (loop)" 4 |
851 | .IX Item "ev_loop_verify (loop)" |
851 | .IX Item "ev_loop_verify (loop)" |
852 | This function only does something when \f(CW\*(C`EV_VERIFY\*(C'\fR support has been |
852 | This function only does something when \f(CW\*(C`EV_VERIFY\*(C'\fR support has been |
853 | compiled in. It tries to go through all internal structures and checks |
853 | compiled in. It tries to go through all internal structures and checks |
854 | them for validity. If anything is found to be inconsistent, it will print |
854 | them for validity. If anything is found to be inconsistent, it will print |
… | |
… | |
862 | A watcher is a structure that you create and register to record your |
862 | A watcher is a structure that you create and register to record your |
863 | interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to |
863 | interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to |
864 | become readable, you would create an \f(CW\*(C`ev_io\*(C'\fR watcher for that: |
864 | become readable, you would create an \f(CW\*(C`ev_io\*(C'\fR watcher for that: |
865 | .PP |
865 | .PP |
866 | .Vb 5 |
866 | .Vb 5 |
867 | \& static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
867 | \& static void my_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
868 | \& { |
868 | \& { |
869 | \& ev_io_stop (w); |
869 | \& ev_io_stop (w); |
870 | \& ev_unloop (loop, EVUNLOOP_ALL); |
870 | \& ev_unloop (loop, EVUNLOOP_ALL); |
871 | \& } |
871 | \& } |
872 | \& |
872 | \& |
873 | \& struct ev_loop *loop = ev_default_loop (0); |
873 | \& struct ev_loop *loop = ev_default_loop (0); |
874 | \& struct ev_io stdin_watcher; |
874 | \& struct ev_io stdin_watcher; |
875 | \& ev_init (&stdin_watcher, my_cb); |
875 | \& ev_init (&stdin_watcher, my_cb); |
876 | \& ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ); |
876 | \& ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ); |
877 | \& ev_io_start (loop, &stdin_watcher); |
877 | \& ev_io_start (loop, &stdin_watcher); |
878 | \& ev_loop (loop, 0); |
878 | \& ev_loop (loop, 0); |
879 | .Ve |
879 | .Ve |
880 | .PP |
880 | .PP |
881 | As you can see, you are responsible for allocating the memory for your |
881 | As you can see, you are responsible for allocating the memory for your |
882 | watcher structures (and it is usually a bad idea to do this on the stack, |
882 | watcher structures (and it is usually a bad idea to do this on the stack, |
883 | although this can sometimes be quite valid). |
883 | although this can sometimes be quite valid). |
884 | .PP |
884 | .PP |
885 | Each watcher structure must be initialised by a call to \f(CW\*(C`ev_init |
885 | Each watcher structure must be initialised by a call to \f(CW\*(C`ev_init |
886 | (watcher *, callback)\*(C'\fR, which expects a callback to be provided. This |
886 | (watcher *, callback)\*(C'\fR, which expects a callback to be provided. This |
887 | callback gets invoked each time the event occurs (or, in the case of io |
887 | callback gets invoked each time the event occurs (or, in the case of I/O |
888 | watchers, each time the event loop detects that the file descriptor given |
888 | watchers, each time the event loop detects that the file descriptor given |
889 | is readable and/or writable). |
889 | is readable and/or writable). |
890 | .PP |
890 | .PP |
891 | Each watcher type has its own \f(CW\*(C`ev_<type>_set (watcher *, ...)\*(C'\fR macro |
891 | Each watcher type has its own \f(CW\*(C`ev_<type>_set (watcher *, ...)\*(C'\fR macro |
892 | with arguments specific to this watcher type. There is also a macro |
892 | with arguments specific to this watcher type. There is also a macro |
… | |
… | |
972 | .IX Item "EV_ASYNC" |
972 | .IX Item "EV_ASYNC" |
973 | The given async watcher has been asynchronously notified (see \f(CW\*(C`ev_async\*(C'\fR). |
973 | The given async watcher has been asynchronously notified (see \f(CW\*(C`ev_async\*(C'\fR). |
974 | .ie n .IP """EV_ERROR""" 4 |
974 | .ie n .IP """EV_ERROR""" 4 |
975 | .el .IP "\f(CWEV_ERROR\fR" 4 |
975 | .el .IP "\f(CWEV_ERROR\fR" 4 |
976 | .IX Item "EV_ERROR" |
976 | .IX Item "EV_ERROR" |
977 | An unspecified error has occured, the watcher has been stopped. This might |
977 | An unspecified error has occurred, the watcher has been stopped. This might |
978 | happen because the watcher could not be properly started because libev |
978 | happen because the watcher could not be properly started because libev |
979 | ran out of memory, a file descriptor was found to be closed or any other |
979 | ran out of memory, a file descriptor was found to be closed or any other |
980 | problem. You best act on it by reporting the problem and somehow coping |
980 | problem. You best act on it by reporting the problem and somehow coping |
981 | with the watcher being stopped. |
981 | with the watcher being stopped. |
982 | .Sp |
982 | .Sp |
983 | Libev will usually signal a few \*(L"dummy\*(R" events together with an error, |
983 | Libev will usually signal a few \*(L"dummy\*(R" events together with an error, |
984 | for example it might indicate that a fd is readable or writable, and if |
984 | for example it might indicate that a fd is readable or writable, and if |
985 | your callbacks is well-written it can just attempt the operation and cope |
985 | your callbacks is well-written it can just attempt the operation and cope |
986 | with the error from \fIread()\fR or \fIwrite()\fR. This will not work in multithreaded |
986 | with the error from \fIread()\fR or \fIwrite()\fR. This will not work in multi-threaded |
987 | programs, though, so beware. |
987 | programs, though, so beware. |
988 | .Sh "\s-1GENERIC\s0 \s-1WATCHER\s0 \s-1FUNCTIONS\s0" |
988 | .Sh "\s-1GENERIC\s0 \s-1WATCHER\s0 \s-1FUNCTIONS\s0" |
989 | .IX Subsection "GENERIC WATCHER FUNCTIONS" |
989 | .IX Subsection "GENERIC WATCHER FUNCTIONS" |
990 | In the following description, \f(CW\*(C`TYPE\*(C'\fR stands for the watcher type, |
990 | In the following description, \f(CW\*(C`TYPE\*(C'\fR stands for the watcher type, |
991 | e.g. \f(CW\*(C`timer\*(C'\fR for \f(CW\*(C`ev_timer\*(C'\fR watchers and \f(CW\*(C`io\*(C'\fR for \f(CW\*(C`ev_io\*(C'\fR watchers. |
991 | e.g. \f(CW\*(C`timer\*(C'\fR for \f(CW\*(C`ev_timer\*(C'\fR watchers and \f(CW\*(C`io\*(C'\fR for \f(CW\*(C`ev_io\*(C'\fR watchers. |
… | |
… | |
1016 | Although some watcher types do not have type-specific arguments |
1016 | Although some watcher types do not have type-specific arguments |
1017 | (e.g. \f(CW\*(C`ev_prepare\*(C'\fR) you still need to call its \f(CW\*(C`set\*(C'\fR macro. |
1017 | (e.g. \f(CW\*(C`ev_prepare\*(C'\fR) you still need to call its \f(CW\*(C`set\*(C'\fR macro. |
1018 | .ie n .IP """ev_TYPE_init"" (ev_TYPE *watcher, callback, [args])" 4 |
1018 | .ie n .IP """ev_TYPE_init"" (ev_TYPE *watcher, callback, [args])" 4 |
1019 | .el .IP "\f(CWev_TYPE_init\fR (ev_TYPE *watcher, callback, [args])" 4 |
1019 | .el .IP "\f(CWev_TYPE_init\fR (ev_TYPE *watcher, callback, [args])" 4 |
1020 | .IX Item "ev_TYPE_init (ev_TYPE *watcher, callback, [args])" |
1020 | .IX Item "ev_TYPE_init (ev_TYPE *watcher, callback, [args])" |
1021 | This convinience macro rolls both \f(CW\*(C`ev_init\*(C'\fR and \f(CW\*(C`ev_TYPE_set\*(C'\fR macro |
1021 | This convenience macro rolls both \f(CW\*(C`ev_init\*(C'\fR and \f(CW\*(C`ev_TYPE_set\*(C'\fR macro |
1022 | calls into a single call. This is the most convinient method to initialise |
1022 | calls into a single call. This is the most convenient method to initialise |
1023 | a watcher. The same limitations apply, of course. |
1023 | a watcher. The same limitations apply, of course. |
1024 | .ie n .IP """ev_TYPE_start"" (loop *, ev_TYPE *watcher)" 4 |
1024 | .ie n .IP """ev_TYPE_start"" (loop *, ev_TYPE *watcher)" 4 |
1025 | .el .IP "\f(CWev_TYPE_start\fR (loop *, ev_TYPE *watcher)" 4 |
1025 | .el .IP "\f(CWev_TYPE_start\fR (loop *, ev_TYPE *watcher)" 4 |
1026 | .IX Item "ev_TYPE_start (loop *, ev_TYPE *watcher)" |
1026 | .IX Item "ev_TYPE_start (loop *, ev_TYPE *watcher)" |
1027 | Starts (activates) the given watcher. Only active watchers will receive |
1027 | Starts (activates) the given watcher. Only active watchers will receive |
… | |
… | |
1102 | don't want to allocate memory and store a pointer to it in that data |
1102 | don't want to allocate memory and store a pointer to it in that data |
1103 | member, you can also \*(L"subclass\*(R" the watcher type and provide your own |
1103 | member, you can also \*(L"subclass\*(R" the watcher type and provide your own |
1104 | data: |
1104 | data: |
1105 | .PP |
1105 | .PP |
1106 | .Vb 7 |
1106 | .Vb 7 |
1107 | \& struct my_io |
1107 | \& struct my_io |
1108 | \& { |
1108 | \& { |
1109 | \& struct ev_io io; |
1109 | \& struct ev_io io; |
1110 | \& int otherfd; |
1110 | \& int otherfd; |
1111 | \& void *somedata; |
1111 | \& void *somedata; |
1112 | \& struct whatever *mostinteresting; |
1112 | \& struct whatever *mostinteresting; |
1113 | \& } |
1113 | \& } |
1114 | .Ve |
1114 | .Ve |
1115 | .PP |
1115 | .PP |
1116 | And since your callback will be called with a pointer to the watcher, you |
1116 | And since your callback will be called with a pointer to the watcher, you |
1117 | can cast it back to your own type: |
1117 | can cast it back to your own type: |
1118 | .PP |
1118 | .PP |
1119 | .Vb 5 |
1119 | .Vb 5 |
1120 | \& static void my_cb (struct ev_loop *loop, struct ev_io *w_, int revents) |
1120 | \& static void my_cb (struct ev_loop *loop, struct ev_io *w_, int revents) |
1121 | \& { |
1121 | \& { |
1122 | \& struct my_io *w = (struct my_io *)w_; |
1122 | \& struct my_io *w = (struct my_io *)w_; |
1123 | \& ... |
1123 | \& ... |
1124 | \& } |
1124 | \& } |
1125 | .Ve |
1125 | .Ve |
1126 | .PP |
1126 | .PP |
1127 | More interesting and less C\-conformant ways of casting your callback type |
1127 | More interesting and less C\-conformant ways of casting your callback type |
1128 | instead have been omitted. |
1128 | instead have been omitted. |
1129 | .PP |
1129 | .PP |
1130 | Another common scenario is having some data structure with multiple |
1130 | Another common scenario is having some data structure with multiple |
1131 | watchers: |
1131 | watchers: |
1132 | .PP |
1132 | .PP |
1133 | .Vb 6 |
1133 | .Vb 6 |
1134 | \& struct my_biggy |
1134 | \& struct my_biggy |
1135 | \& { |
1135 | \& { |
1136 | \& int some_data; |
1136 | \& int some_data; |
1137 | \& ev_timer t1; |
1137 | \& ev_timer t1; |
1138 | \& ev_timer t2; |
1138 | \& ev_timer t2; |
1139 | \& } |
1139 | \& } |
1140 | .Ve |
1140 | .Ve |
1141 | .PP |
1141 | .PP |
1142 | In this case getting the pointer to \f(CW\*(C`my_biggy\*(C'\fR is a bit more complicated, |
1142 | In this case getting the pointer to \f(CW\*(C`my_biggy\*(C'\fR is a bit more complicated, |
1143 | you need to use \f(CW\*(C`offsetof\*(C'\fR: |
1143 | you need to use \f(CW\*(C`offsetof\*(C'\fR: |
1144 | .PP |
1144 | .PP |
1145 | .Vb 1 |
1145 | .Vb 1 |
1146 | \& #include <stddef.h> |
1146 | \& #include <stddef.h> |
1147 | \& |
1147 | \& |
1148 | \& static void |
1148 | \& static void |
1149 | \& t1_cb (EV_P_ struct ev_timer *w, int revents) |
1149 | \& t1_cb (EV_P_ struct ev_timer *w, int revents) |
1150 | \& { |
1150 | \& { |
1151 | \& struct my_biggy big = (struct my_biggy * |
1151 | \& struct my_biggy big = (struct my_biggy * |
1152 | \& (((char *)w) \- offsetof (struct my_biggy, t1)); |
1152 | \& (((char *)w) \- offsetof (struct my_biggy, t1)); |
1153 | \& } |
1153 | \& } |
1154 | \& |
1154 | \& |
1155 | \& static void |
1155 | \& static void |
1156 | \& t2_cb (EV_P_ struct ev_timer *w, int revents) |
1156 | \& t2_cb (EV_P_ struct ev_timer *w, int revents) |
1157 | \& { |
1157 | \& { |
1158 | \& struct my_biggy big = (struct my_biggy * |
1158 | \& struct my_biggy big = (struct my_biggy * |
1159 | \& (((char *)w) \- offsetof (struct my_biggy, t2)); |
1159 | \& (((char *)w) \- offsetof (struct my_biggy, t2)); |
1160 | \& } |
1160 | \& } |
1161 | .Ve |
1161 | .Ve |
1162 | .SH "WATCHER TYPES" |
1162 | .SH "WATCHER TYPES" |
1163 | .IX Header "WATCHER TYPES" |
1163 | .IX Header "WATCHER TYPES" |
1164 | This section describes each watcher in detail, but will not repeat |
1164 | This section describes each watcher in detail, but will not repeat |
1165 | information given in the last section. Any initialisation/set macros, |
1165 | information given in the last section. Any initialisation/set macros, |
… | |
… | |
1195 | .PP |
1195 | .PP |
1196 | Another thing you have to watch out for is that it is quite easy to |
1196 | Another thing you have to watch out for is that it is quite easy to |
1197 | receive \*(L"spurious\*(R" readiness notifications, that is your callback might |
1197 | receive \*(L"spurious\*(R" readiness notifications, that is your callback might |
1198 | be called with \f(CW\*(C`EV_READ\*(C'\fR but a subsequent \f(CW\*(C`read\*(C'\fR(2) will actually block |
1198 | be called with \f(CW\*(C`EV_READ\*(C'\fR but a subsequent \f(CW\*(C`read\*(C'\fR(2) will actually block |
1199 | because there is no data. Not only are some backends known to create a |
1199 | because there is no data. Not only are some backends known to create a |
1200 | lot of those (for example solaris ports), it is very easy to get into |
1200 | lot of those (for example Solaris ports), it is very easy to get into |
1201 | this situation even with a relatively standard program structure. Thus |
1201 | this situation even with a relatively standard program structure. Thus |
1202 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
1202 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
1203 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
1203 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
1204 | .PP |
1204 | .PP |
1205 | If you cannot run the fd in non-blocking mode (for example you should not |
1205 | If you cannot run the fd in non-blocking mode (for example you should not |
1206 | play around with an Xlib connection), then you have to seperately re-test |
1206 | play around with an Xlib connection), then you have to separately re-test |
1207 | whether a file descriptor is really ready with a known-to-be good interface |
1207 | whether a file descriptor is really ready with a known-to-be good interface |
1208 | such as poll (fortunately in our Xlib example, Xlib already does this on |
1208 | such as poll (fortunately in our Xlib example, Xlib already does this on |
1209 | its own, so its quite safe to use). |
1209 | its own, so its quite safe to use). |
1210 | .PP |
1210 | .PP |
1211 | \fIThe special problem of disappearing file descriptors\fR |
1211 | \fIThe special problem of disappearing file descriptors\fR |
… | |
… | |
1274 | .PD 0 |
1274 | .PD 0 |
1275 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
1275 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
1276 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
1276 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
1277 | .PD |
1277 | .PD |
1278 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The \f(CW\*(C`fd\*(C'\fR is the file descriptor to |
1278 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The \f(CW\*(C`fd\*(C'\fR is the file descriptor to |
1279 | rceeive events for and events is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or |
1279 | receive events for and events is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or |
1280 | \&\f(CW\*(C`EV_READ | EV_WRITE\*(C'\fR to receive the given events. |
1280 | \&\f(CW\*(C`EV_READ | EV_WRITE\*(C'\fR to receive the given events. |
1281 | .IP "int fd [read\-only]" 4 |
1281 | .IP "int fd [read\-only]" 4 |
1282 | .IX Item "int fd [read-only]" |
1282 | .IX Item "int fd [read-only]" |
1283 | The file descriptor being watched. |
1283 | The file descriptor being watched. |
1284 | .IP "int events [read\-only]" 4 |
1284 | .IP "int events [read\-only]" 4 |
… | |
… | |
1291 | Example: Call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
1291 | Example: Call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
1292 | readable, but only once. Since it is likely line-buffered, you could |
1292 | readable, but only once. Since it is likely line-buffered, you could |
1293 | attempt to read a whole line in the callback. |
1293 | attempt to read a whole line in the callback. |
1294 | .PP |
1294 | .PP |
1295 | .Vb 6 |
1295 | .Vb 6 |
1296 | \& static void |
1296 | \& static void |
1297 | \& stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1297 | \& stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1298 | \& { |
1298 | \& { |
1299 | \& ev_io_stop (loop, w); |
1299 | \& ev_io_stop (loop, w); |
1300 | \& .. read from stdin here (or from w\->fd) and haqndle any I/O errors |
1300 | \& .. read from stdin here (or from w\->fd) and haqndle any I/O errors |
1301 | \& } |
1301 | \& } |
1302 | \& |
1302 | \& |
1303 | \& ... |
1303 | \& ... |
1304 | \& struct ev_loop *loop = ev_default_init (0); |
1304 | \& struct ev_loop *loop = ev_default_init (0); |
1305 | \& struct ev_io stdin_readable; |
1305 | \& struct ev_io stdin_readable; |
1306 | \& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
1306 | \& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
1307 | \& ev_io_start (loop, &stdin_readable); |
1307 | \& ev_io_start (loop, &stdin_readable); |
1308 | \& ev_loop (loop, 0); |
1308 | \& ev_loop (loop, 0); |
1309 | .Ve |
1309 | .Ve |
1310 | .ie n .Sh """ev_timer"" \- relative and optionally repeating timeouts" |
1310 | .ie n .Sh """ev_timer"" \- relative and optionally repeating timeouts" |
1311 | .el .Sh "\f(CWev_timer\fP \- relative and optionally repeating timeouts" |
1311 | .el .Sh "\f(CWev_timer\fP \- relative and optionally repeating timeouts" |
1312 | .IX Subsection "ev_timer - relative and optionally repeating timeouts" |
1312 | .IX Subsection "ev_timer - relative and optionally repeating timeouts" |
1313 | Timer watchers are simple relative timers that generate an event after a |
1313 | Timer watchers are simple relative timers that generate an event after a |
1314 | given time, and optionally repeating in regular intervals after that. |
1314 | given time, and optionally repeating in regular intervals after that. |
1315 | .PP |
1315 | .PP |
1316 | The timers are based on real time, that is, if you register an event that |
1316 | The timers are based on real time, that is, if you register an event that |
1317 | times out after an hour and you reset your system clock to january last |
1317 | times out after an hour and you reset your system clock to January last |
1318 | year, it will still time out after (roughly) and hour. \*(L"Roughly\*(R" because |
1318 | year, it will still time out after (roughly) and hour. \*(L"Roughly\*(R" because |
1319 | detecting time jumps is hard, and some inaccuracies are unavoidable (the |
1319 | detecting time jumps is hard, and some inaccuracies are unavoidable (the |
1320 | monotonic clock option helps a lot here). |
1320 | monotonic clock option helps a lot here). |
1321 | .PP |
1321 | .PP |
1322 | The relative timeouts are calculated relative to the \f(CW\*(C`ev_now ()\*(C'\fR |
1322 | The relative timeouts are calculated relative to the \f(CW\*(C`ev_now ()\*(C'\fR |
… | |
… | |
1327 | .PP |
1327 | .PP |
1328 | .Vb 1 |
1328 | .Vb 1 |
1329 | \& ev_timer_set (&timer, after + ev_now () \- ev_time (), 0.); |
1329 | \& ev_timer_set (&timer, after + ev_now () \- ev_time (), 0.); |
1330 | .Ve |
1330 | .Ve |
1331 | .PP |
1331 | .PP |
1332 | The callback is guarenteed to be invoked only after its timeout has passed, |
1332 | The callback is guaranteed to be invoked only after its timeout has passed, |
1333 | but if multiple timers become ready during the same loop iteration then |
1333 | but if multiple timers become ready during the same loop iteration then |
1334 | order of execution is undefined. |
1334 | order of execution is undefined. |
1335 | .PP |
1335 | .PP |
1336 | \fIWatcher-Specific Functions and Data Members\fR |
1336 | \fIWatcher-Specific Functions and Data Members\fR |
1337 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1337 | .IX Subsection "Watcher-Specific Functions and Data Members" |
… | |
… | |
1357 | This will act as if the timer timed out and restart it again if it is |
1357 | This will act as if the timer timed out and restart it again if it is |
1358 | repeating. The exact semantics are: |
1358 | repeating. The exact semantics are: |
1359 | .Sp |
1359 | .Sp |
1360 | If the timer is pending, its pending status is cleared. |
1360 | If the timer is pending, its pending status is cleared. |
1361 | .Sp |
1361 | .Sp |
1362 | If the timer is started but nonrepeating, stop it (as if it timed out). |
1362 | If the timer is started but non-repeating, stop it (as if it timed out). |
1363 | .Sp |
1363 | .Sp |
1364 | If the timer is repeating, either start it if necessary (with the |
1364 | If the timer is repeating, either start it if necessary (with the |
1365 | \&\f(CW\*(C`repeat\*(C'\fR value), or reset the running timer to the \f(CW\*(C`repeat\*(C'\fR value. |
1365 | \&\f(CW\*(C`repeat\*(C'\fR value), or reset the running timer to the \f(CW\*(C`repeat\*(C'\fR value. |
1366 | .Sp |
1366 | .Sp |
1367 | This sounds a bit complicated, but here is a useful and typical |
1367 | This sounds a bit complicated, but here is a useful and typical |
1368 | example: Imagine you have a tcp connection and you want a so-called idle |
1368 | example: Imagine you have a \s-1TCP\s0 connection and you want a so-called idle |
1369 | timeout, that is, you want to be called when there have been, say, 60 |
1369 | timeout, that is, you want to be called when there have been, say, 60 |
1370 | seconds of inactivity on the socket. The easiest way to do this is to |
1370 | seconds of inactivity on the socket. The easiest way to do this is to |
1371 | configure an \f(CW\*(C`ev_timer\*(C'\fR with a \f(CW\*(C`repeat\*(C'\fR value of \f(CW60\fR and then call |
1371 | configure an \f(CW\*(C`ev_timer\*(C'\fR with a \f(CW\*(C`repeat\*(C'\fR value of \f(CW60\fR and then call |
1372 | \&\f(CW\*(C`ev_timer_again\*(C'\fR each time you successfully read or write some data. If |
1372 | \&\f(CW\*(C`ev_timer_again\*(C'\fR each time you successfully read or write some data. If |
1373 | you go into an idle state where you do not expect data to travel on the |
1373 | you go into an idle state where you do not expect data to travel on the |
… | |
… | |
1400 | .IX Subsection "Examples" |
1400 | .IX Subsection "Examples" |
1401 | .PP |
1401 | .PP |
1402 | Example: Create a timer that fires after 60 seconds. |
1402 | Example: Create a timer that fires after 60 seconds. |
1403 | .PP |
1403 | .PP |
1404 | .Vb 5 |
1404 | .Vb 5 |
1405 | \& static void |
1405 | \& static void |
1406 | \& one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1406 | \& one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1407 | \& { |
1407 | \& { |
1408 | \& .. one minute over, w is actually stopped right here |
1408 | \& .. one minute over, w is actually stopped right here |
1409 | \& } |
1409 | \& } |
1410 | \& |
1410 | \& |
1411 | \& struct ev_timer mytimer; |
1411 | \& struct ev_timer mytimer; |
1412 | \& ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
1412 | \& ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
1413 | \& ev_timer_start (loop, &mytimer); |
1413 | \& ev_timer_start (loop, &mytimer); |
1414 | .Ve |
1414 | .Ve |
1415 | .PP |
1415 | .PP |
1416 | Example: Create a timeout timer that times out after 10 seconds of |
1416 | Example: Create a timeout timer that times out after 10 seconds of |
1417 | inactivity. |
1417 | inactivity. |
1418 | .PP |
1418 | .PP |
1419 | .Vb 5 |
1419 | .Vb 5 |
1420 | \& static void |
1420 | \& static void |
1421 | \& timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1421 | \& timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1422 | \& { |
1422 | \& { |
1423 | \& .. ten seconds without any activity |
1423 | \& .. ten seconds without any activity |
1424 | \& } |
1424 | \& } |
1425 | \& |
1425 | \& |
1426 | \& struct ev_timer mytimer; |
1426 | \& struct ev_timer mytimer; |
1427 | \& ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */ |
1427 | \& ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */ |
1428 | \& ev_timer_again (&mytimer); /* start timer */ |
1428 | \& ev_timer_again (&mytimer); /* start timer */ |
1429 | \& ev_loop (loop, 0); |
1429 | \& ev_loop (loop, 0); |
1430 | \& |
1430 | \& |
1431 | \& // and in some piece of code that gets executed on any "activity": |
1431 | \& // and in some piece of code that gets executed on any "activity": |
1432 | \& // reset the timeout to start ticking again at 10 seconds |
1432 | \& // reset the timeout to start ticking again at 10 seconds |
1433 | \& ev_timer_again (&mytimer); |
1433 | \& ev_timer_again (&mytimer); |
1434 | .Ve |
1434 | .Ve |
1435 | .ie n .Sh """ev_periodic"" \- to cron or not to cron?" |
1435 | .ie n .Sh """ev_periodic"" \- to cron or not to cron?" |
1436 | .el .Sh "\f(CWev_periodic\fP \- to cron or not to cron?" |
1436 | .el .Sh "\f(CWev_periodic\fP \- to cron or not to cron?" |
1437 | .IX Subsection "ev_periodic - to cron or not to cron?" |
1437 | .IX Subsection "ev_periodic - to cron or not to cron?" |
1438 | Periodic watchers are also timers of a kind, but they are very versatile |
1438 | Periodic watchers are also timers of a kind, but they are very versatile |
1439 | (and unfortunately a bit complex). |
1439 | (and unfortunately a bit complex). |
1440 | .PP |
1440 | .PP |
1441 | Unlike \f(CW\*(C`ev_timer\*(C'\fR's, they are not based on real time (or relative time) |
1441 | Unlike \f(CW\*(C`ev_timer\*(C'\fR's, they are not based on real time (or relative time) |
1442 | but on wallclock time (absolute time). You can tell a periodic watcher |
1442 | but on wall clock time (absolute time). You can tell a periodic watcher |
1443 | to trigger after some specific point in time. For example, if you tell a |
1443 | to trigger after some specific point in time. For example, if you tell a |
1444 | periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () |
1444 | periodic watcher to trigger in 10 seconds (by specifying e.g. \f(CW\*(C`ev_now () |
1445 | + 10.\*(C'\fR, that is, an absolute time not a delay) and then reset your system |
1445 | + 10.\*(C'\fR, that is, an absolute time not a delay) and then reset your system |
1446 | clock to january of the previous year, then it will take more than year |
1446 | clock to January of the previous year, then it will take more than year |
1447 | to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would still trigger |
1447 | to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would still trigger |
1448 | roughly 10 seconds later as it uses a relative timeout). |
1448 | roughly 10 seconds later as it uses a relative timeout). |
1449 | .PP |
1449 | .PP |
1450 | \&\f(CW\*(C`ev_periodic\*(C'\fRs can also be used to implement vastly more complex timers, |
1450 | \&\f(CW\*(C`ev_periodic\*(C'\fRs can also be used to implement vastly more complex timers, |
1451 | such as triggering an event on each \*(L"midnight, local time\*(R", or other |
1451 | such as triggering an event on each \*(L"midnight, local time\*(R", or other |
1452 | complicated, rules. |
1452 | complicated, rules. |
1453 | .PP |
1453 | .PP |
1454 | As with timers, the callback is guarenteed to be invoked only when the |
1454 | As with timers, the callback is guaranteed to be invoked only when the |
1455 | time (\f(CW\*(C`at\*(C'\fR) has passed, but if multiple periodic timers become ready |
1455 | time (\f(CW\*(C`at\*(C'\fR) has passed, but if multiple periodic timers become ready |
1456 | during the same loop iteration then order of execution is undefined. |
1456 | during the same loop iteration then order of execution is undefined. |
1457 | .PP |
1457 | .PP |
1458 | \fIWatcher-Specific Functions and Data Members\fR |
1458 | \fIWatcher-Specific Functions and Data Members\fR |
1459 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1459 | .IX Subsection "Watcher-Specific Functions and Data Members" |
… | |
… | |
1467 | operation, and we will explain them from simplest to complex: |
1467 | operation, and we will explain them from simplest to complex: |
1468 | .RS 4 |
1468 | .RS 4 |
1469 | .IP "\(bu" 4 |
1469 | .IP "\(bu" 4 |
1470 | absolute timer (at = time, interval = reschedule_cb = 0) |
1470 | absolute timer (at = time, interval = reschedule_cb = 0) |
1471 | .Sp |
1471 | .Sp |
1472 | In this configuration the watcher triggers an event after the wallclock |
1472 | In this configuration the watcher triggers an event after the wall clock |
1473 | time \f(CW\*(C`at\*(C'\fR has passed and doesn't repeat. It will not adjust when a time |
1473 | time \f(CW\*(C`at\*(C'\fR has passed and doesn't repeat. It will not adjust when a time |
1474 | jump occurs, that is, if it is to be run at January 1st 2011 then it will |
1474 | jump occurs, that is, if it is to be run at January 1st 2011 then it will |
1475 | run when the system time reaches or surpasses this time. |
1475 | run when the system time reaches or surpasses this time. |
1476 | .IP "\(bu" 4 |
1476 | .IP "\(bu" 4 |
1477 | repeating interval timer (at = offset, interval > 0, reschedule_cb = 0) |
1477 | repeating interval timer (at = offset, interval > 0, reschedule_cb = 0) |
… | |
… | |
1487 | .Vb 1 |
1487 | .Vb 1 |
1488 | \& ev_periodic_set (&periodic, 0., 3600., 0); |
1488 | \& ev_periodic_set (&periodic, 0., 3600., 0); |
1489 | .Ve |
1489 | .Ve |
1490 | .Sp |
1490 | .Sp |
1491 | This doesn't mean there will always be 3600 seconds in between triggers, |
1491 | This doesn't mean there will always be 3600 seconds in between triggers, |
1492 | but only that the the callback will be called when the system time shows a |
1492 | but only that the callback will be called when the system time shows a |
1493 | full hour (\s-1UTC\s0), or more correctly, when the system time is evenly divisible |
1493 | full hour (\s-1UTC\s0), or more correctly, when the system time is evenly divisible |
1494 | by 3600. |
1494 | by 3600. |
1495 | .Sp |
1495 | .Sp |
1496 | Another way to think about it (for the mathematically inclined) is that |
1496 | Another way to think about it (for the mathematically inclined) is that |
1497 | \&\f(CW\*(C`ev_periodic\*(C'\fR will try to run the callback in this mode at the next possible |
1497 | \&\f(CW\*(C`ev_periodic\*(C'\fR will try to run the callback in this mode at the next possible |
… | |
… | |
1499 | .Sp |
1499 | .Sp |
1500 | For numerical stability it is preferable that the \f(CW\*(C`at\*(C'\fR value is near |
1500 | For numerical stability it is preferable that the \f(CW\*(C`at\*(C'\fR value is near |
1501 | \&\f(CW\*(C`ev_now ()\*(C'\fR (the current time), but there is no range requirement for |
1501 | \&\f(CW\*(C`ev_now ()\*(C'\fR (the current time), but there is no range requirement for |
1502 | this value, and in fact is often specified as zero. |
1502 | this value, and in fact is often specified as zero. |
1503 | .Sp |
1503 | .Sp |
1504 | Note also that there is an upper limit to how often a timer can fire (cpu |
1504 | Note also that there is an upper limit to how often a timer can fire (\s-1CPU\s0 |
1505 | speed for example), so if \f(CW\*(C`interval\*(C'\fR is very small then timing stability |
1505 | speed for example), so if \f(CW\*(C`interval\*(C'\fR is very small then timing stability |
1506 | will of course detoriate. Libev itself tries to be exact to be about one |
1506 | will of course deteriorate. Libev itself tries to be exact to be about one |
1507 | millisecond (if the \s-1OS\s0 supports it and the machine is fast enough). |
1507 | millisecond (if the \s-1OS\s0 supports it and the machine is fast enough). |
1508 | .IP "\(bu" 4 |
1508 | .IP "\(bu" 4 |
1509 | manual reschedule mode (at and interval ignored, reschedule_cb = callback) |
1509 | manual reschedule mode (at and interval ignored, reschedule_cb = callback) |
1510 | .Sp |
1510 | .Sp |
1511 | In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`at\*(C'\fR are both being |
1511 | In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`at\*(C'\fR are both being |
… | |
… | |
1577 | \fIExamples\fR |
1577 | \fIExamples\fR |
1578 | .IX Subsection "Examples" |
1578 | .IX Subsection "Examples" |
1579 | .PP |
1579 | .PP |
1580 | Example: Call a callback every hour, or, more precisely, whenever the |
1580 | Example: Call a callback every hour, or, more precisely, whenever the |
1581 | system clock is divisible by 3600. The callback invocation times have |
1581 | system clock is divisible by 3600. The callback invocation times have |
1582 | potentially a lot of jittering, but good long-term stability. |
1582 | potentially a lot of jitter, but good long-term stability. |
1583 | .PP |
1583 | .PP |
1584 | .Vb 5 |
1584 | .Vb 5 |
1585 | \& static void |
1585 | \& static void |
1586 | \& clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1586 | \& clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1587 | \& { |
1587 | \& { |
1588 | \& ... its now a full hour (UTC, or TAI or whatever your clock follows) |
1588 | \& ... its now a full hour (UTC, or TAI or whatever your clock follows) |
1589 | \& } |
1589 | \& } |
1590 | \& |
1590 | \& |
1591 | \& struct ev_periodic hourly_tick; |
1591 | \& struct ev_periodic hourly_tick; |
1592 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1592 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1593 | \& ev_periodic_start (loop, &hourly_tick); |
1593 | \& ev_periodic_start (loop, &hourly_tick); |
1594 | .Ve |
1594 | .Ve |
1595 | .PP |
1595 | .PP |
1596 | Example: The same as above, but use a reschedule callback to do it: |
1596 | Example: The same as above, but use a reschedule callback to do it: |
1597 | .PP |
1597 | .PP |
1598 | .Vb 1 |
1598 | .Vb 1 |
1599 | \& #include <math.h> |
1599 | \& #include <math.h> |
1600 | \& |
1600 | \& |
1601 | \& static ev_tstamp |
1601 | \& static ev_tstamp |
1602 | \& my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
1602 | \& my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
1603 | \& { |
1603 | \& { |
1604 | \& return fmod (now, 3600.) + 3600.; |
1604 | \& return fmod (now, 3600.) + 3600.; |
1605 | \& } |
1605 | \& } |
1606 | \& |
1606 | \& |
1607 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1607 | \& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1608 | .Ve |
1608 | .Ve |
1609 | .PP |
1609 | .PP |
1610 | Example: Call a callback every hour, starting now: |
1610 | Example: Call a callback every hour, starting now: |
1611 | .PP |
1611 | .PP |
1612 | .Vb 4 |
1612 | .Vb 4 |
1613 | \& struct ev_periodic hourly_tick; |
1613 | \& struct ev_periodic hourly_tick; |
1614 | \& ev_periodic_init (&hourly_tick, clock_cb, |
1614 | \& ev_periodic_init (&hourly_tick, clock_cb, |
1615 | \& fmod (ev_now (loop), 3600.), 3600., 0); |
1615 | \& fmod (ev_now (loop), 3600.), 3600., 0); |
1616 | \& ev_periodic_start (loop, &hourly_tick); |
1616 | \& ev_periodic_start (loop, &hourly_tick); |
1617 | .Ve |
1617 | .Ve |
1618 | .ie n .Sh """ev_signal"" \- signal me when a signal gets signalled!" |
1618 | .ie n .Sh """ev_signal"" \- signal me when a signal gets signalled!" |
1619 | .el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled!" |
1619 | .el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled!" |
1620 | .IX Subsection "ev_signal - signal me when a signal gets signalled!" |
1620 | .IX Subsection "ev_signal - signal me when a signal gets signalled!" |
1621 | Signal watchers will trigger an event when the process receives a specific |
1621 | Signal watchers will trigger an event when the process receives a specific |
… | |
… | |
1629 | as you don't register any with libev). Similarly, when the last signal |
1629 | as you don't register any with libev). Similarly, when the last signal |
1630 | watcher for a signal is stopped libev will reset the signal handler to |
1630 | watcher for a signal is stopped libev will reset the signal handler to |
1631 | \&\s-1SIG_DFL\s0 (regardless of what it was set to before). |
1631 | \&\s-1SIG_DFL\s0 (regardless of what it was set to before). |
1632 | .PP |
1632 | .PP |
1633 | If possible and supported, libev will install its handlers with |
1633 | If possible and supported, libev will install its handlers with |
1634 | \&\f(CW\*(C`SA_RESTART\*(C'\fR behaviour enabled, so syscalls should not be unduly |
1634 | \&\f(CW\*(C`SA_RESTART\*(C'\fR behaviour enabled, so system calls should not be unduly |
1635 | interrupted. If you have a problem with syscalls getting interrupted by |
1635 | interrupted. If you have a problem with system calls getting interrupted by |
1636 | signals you can block all signals in an \f(CW\*(C`ev_check\*(C'\fR watcher and unblock |
1636 | signals you can block all signals in an \f(CW\*(C`ev_check\*(C'\fR watcher and unblock |
1637 | them in an \f(CW\*(C`ev_prepare\*(C'\fR watcher. |
1637 | them in an \f(CW\*(C`ev_prepare\*(C'\fR watcher. |
1638 | .PP |
1638 | .PP |
1639 | \fIWatcher-Specific Functions and Data Members\fR |
1639 | \fIWatcher-Specific Functions and Data Members\fR |
1640 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1640 | .IX Subsection "Watcher-Specific Functions and Data Members" |
… | |
… | |
1654 | .IX Subsection "Examples" |
1654 | .IX Subsection "Examples" |
1655 | .PP |
1655 | .PP |
1656 | Example: Try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
1656 | Example: Try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
1657 | .PP |
1657 | .PP |
1658 | .Vb 5 |
1658 | .Vb 5 |
1659 | \& static void |
1659 | \& static void |
1660 | \& sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1660 | \& sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1661 | \& { |
1661 | \& { |
1662 | \& ev_unloop (loop, EVUNLOOP_ALL); |
1662 | \& ev_unloop (loop, EVUNLOOP_ALL); |
1663 | \& } |
1663 | \& } |
1664 | \& |
1664 | \& |
1665 | \& struct ev_signal signal_watcher; |
1665 | \& struct ev_signal signal_watcher; |
1666 | \& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1666 | \& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1667 | \& ev_signal_start (loop, &sigint_cb); |
1667 | \& ev_signal_start (loop, &sigint_cb); |
1668 | .Ve |
1668 | .Ve |
1669 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
1669 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
1670 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
1670 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
1671 | .IX Subsection "ev_child - watch out for process status changes" |
1671 | .IX Subsection "ev_child - watch out for process status changes" |
1672 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1672 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
… | |
… | |
1674 | is permissible to install a child watcher \fIafter\fR the child has been |
1674 | is permissible to install a child watcher \fIafter\fR the child has been |
1675 | forked (which implies it might have already exited), as long as the event |
1675 | forked (which implies it might have already exited), as long as the event |
1676 | loop isn't entered (or is continued from a watcher). |
1676 | loop isn't entered (or is continued from a watcher). |
1677 | .PP |
1677 | .PP |
1678 | Only the default event loop is capable of handling signals, and therefore |
1678 | Only the default event loop is capable of handling signals, and therefore |
1679 | you can only rgeister child watchers in the default event loop. |
1679 | you can only register child watchers in the default event loop. |
1680 | .PP |
1680 | .PP |
1681 | \fIProcess Interaction\fR |
1681 | \fIProcess Interaction\fR |
1682 | .IX Subsection "Process Interaction" |
1682 | .IX Subsection "Process Interaction" |
1683 | .PP |
1683 | .PP |
1684 | Libev grabs \f(CW\*(C`SIGCHLD\*(C'\fR as soon as the default event loop is |
1684 | Libev grabs \f(CW\*(C`SIGCHLD\*(C'\fR as soon as the default event loop is |
1685 | initialised. This is necessary to guarantee proper behaviour even if |
1685 | initialised. This is necessary to guarantee proper behaviour even if |
1686 | the first child watcher is started after the child exits. The occurance |
1686 | the first child watcher is started after the child exits. The occurrence |
1687 | of \f(CW\*(C`SIGCHLD\*(C'\fR is recorded asynchronously, but child reaping is done |
1687 | of \f(CW\*(C`SIGCHLD\*(C'\fR is recorded asynchronously, but child reaping is done |
1688 | synchronously as part of the event loop processing. Libev always reaps all |
1688 | synchronously as part of the event loop processing. Libev always reaps all |
1689 | children, even ones not watched. |
1689 | children, even ones not watched. |
1690 | .PP |
1690 | .PP |
1691 | \fIOverriding the Built-In Processing\fR |
1691 | \fIOverriding the Built-In Processing\fR |
… | |
… | |
1731 | .PP |
1731 | .PP |
1732 | Example: \f(CW\*(C`fork()\*(C'\fR a new process and install a child handler to wait for |
1732 | Example: \f(CW\*(C`fork()\*(C'\fR a new process and install a child handler to wait for |
1733 | its completion. |
1733 | its completion. |
1734 | .PP |
1734 | .PP |
1735 | .Vb 1 |
1735 | .Vb 1 |
1736 | \& ev_child cw; |
1736 | \& ev_child cw; |
1737 | \& |
1737 | \& |
1738 | \& static void |
1738 | \& static void |
1739 | \& child_cb (EV_P_ struct ev_child *w, int revents) |
1739 | \& child_cb (EV_P_ struct ev_child *w, int revents) |
1740 | \& { |
1740 | \& { |
1741 | \& ev_child_stop (EV_A_ w); |
1741 | \& ev_child_stop (EV_A_ w); |
1742 | \& printf ("process %d exited with status %x\en", w\->rpid, w\->rstatus); |
1742 | \& printf ("process %d exited with status %x\en", w\->rpid, w\->rstatus); |
1743 | \& } |
1743 | \& } |
1744 | \& |
1744 | \& |
1745 | \& pid_t pid = fork (); |
1745 | \& pid_t pid = fork (); |
1746 | \& |
1746 | \& |
1747 | \& if (pid < 0) |
1747 | \& if (pid < 0) |
1748 | \& // error |
1748 | \& // error |
1749 | \& else if (pid == 0) |
1749 | \& else if (pid == 0) |
1750 | \& { |
1750 | \& { |
1751 | \& // the forked child executes here |
1751 | \& // the forked child executes here |
1752 | \& exit (1); |
1752 | \& exit (1); |
1753 | \& } |
1753 | \& } |
1754 | \& else |
1754 | \& else |
1755 | \& { |
1755 | \& { |
1756 | \& ev_child_init (&cw, child_cb, pid, 0); |
1756 | \& ev_child_init (&cw, child_cb, pid, 0); |
1757 | \& ev_child_start (EV_DEFAULT_ &cw); |
1757 | \& ev_child_start (EV_DEFAULT_ &cw); |
1758 | \& } |
1758 | \& } |
1759 | .Ve |
1759 | .Ve |
1760 | .ie n .Sh """ev_stat"" \- did the file attributes just change?" |
1760 | .ie n .Sh """ev_stat"" \- did the file attributes just change?" |
1761 | .el .Sh "\f(CWev_stat\fP \- did the file attributes just change?" |
1761 | .el .Sh "\f(CWev_stat\fP \- did the file attributes just change?" |
1762 | .IX Subsection "ev_stat - did the file attributes just change?" |
1762 | .IX Subsection "ev_stat - did the file attributes just change?" |
1763 | This watches a filesystem path for attribute changes. That is, it calls |
1763 | This watches a file system path for attribute changes. That is, it calls |
1764 | \&\f(CW\*(C`stat\*(C'\fR regularly (or when the \s-1OS\s0 says it changed) and sees if it changed |
1764 | \&\f(CW\*(C`stat\*(C'\fR regularly (or when the \s-1OS\s0 says it changed) and sees if it changed |
1765 | compared to the last time, invoking the callback if it did. |
1765 | compared to the last time, invoking the callback if it did. |
1766 | .PP |
1766 | .PP |
1767 | The path does not need to exist: changing from \*(L"path exists\*(R" to \*(L"path does |
1767 | The path does not need to exist: changing from \*(L"path exists\*(R" to \*(L"path does |
1768 | not exist\*(R" is a status change like any other. The condition \*(L"path does |
1768 | not exist\*(R" is a status change like any other. The condition \*(L"path does |
… | |
… | |
1803 | disabled large file support, you get the 32 bit version of the stat |
1803 | disabled large file support, you get the 32 bit version of the stat |
1804 | structure. When using the library from programs that change the \s-1ABI\s0 to |
1804 | structure. When using the library from programs that change the \s-1ABI\s0 to |
1805 | use 64 bit file offsets the programs will fail. In that case you have to |
1805 | use 64 bit file offsets the programs will fail. In that case you have to |
1806 | compile libev with the same flags to get binary compatibility. This is |
1806 | compile libev with the same flags to get binary compatibility. This is |
1807 | obviously the case with any flags that change the \s-1ABI\s0, but the problem is |
1807 | obviously the case with any flags that change the \s-1ABI\s0, but the problem is |
1808 | most noticably with ev_stat and largefile support. |
1808 | most noticeably with ev_stat and large file support. |
1809 | .PP |
1809 | .PP |
1810 | \fIInotify\fR |
1810 | \fIInotify\fR |
1811 | .IX Subsection "Inotify" |
1811 | .IX Subsection "Inotify" |
1812 | .PP |
1812 | .PP |
1813 | When \f(CW\*(C`inotify (7)\*(C'\fR support has been compiled into libev (generally only |
1813 | When \f(CW\*(C`inotify (7)\*(C'\fR support has been compiled into libev (generally only |
… | |
… | |
1825 | descriptor open on the object at all times). |
1825 | descriptor open on the object at all times). |
1826 | .PP |
1826 | .PP |
1827 | \fIThe special problem of stat time resolution\fR |
1827 | \fIThe special problem of stat time resolution\fR |
1828 | .IX Subsection "The special problem of stat time resolution" |
1828 | .IX Subsection "The special problem of stat time resolution" |
1829 | .PP |
1829 | .PP |
1830 | The \f(CW\*(C`stat ()\*(C'\fR syscall only supports full-second resolution portably, and |
1830 | The \f(CW\*(C`stat ()\*(C'\fR system call only supports full-second resolution portably, and |
1831 | even on systems where the resolution is higher, many filesystems still |
1831 | even on systems where the resolution is higher, many file systems still |
1832 | only support whole seconds. |
1832 | only support whole seconds. |
1833 | .PP |
1833 | .PP |
1834 | That means that, if the time is the only thing that changes, you can |
1834 | That means that, if the time is the only thing that changes, you can |
1835 | easily miss updates: on the first update, \f(CW\*(C`ev_stat\*(C'\fR detects a change and |
1835 | easily miss updates: on the first update, \f(CW\*(C`ev_stat\*(C'\fR detects a change and |
1836 | calls your callback, which does something. When there is another update |
1836 | calls your callback, which does something. When there is another update |
… | |
… | |
1891 | .IP "ev_tstamp interval [read\-only]" 4 |
1891 | .IP "ev_tstamp interval [read\-only]" 4 |
1892 | .IX Item "ev_tstamp interval [read-only]" |
1892 | .IX Item "ev_tstamp interval [read-only]" |
1893 | The specified interval. |
1893 | The specified interval. |
1894 | .IP "const char *path [read\-only]" 4 |
1894 | .IP "const char *path [read\-only]" 4 |
1895 | .IX Item "const char *path [read-only]" |
1895 | .IX Item "const char *path [read-only]" |
1896 | The filesystem path that is being watched. |
1896 | The file system path that is being watched. |
1897 | .PP |
1897 | .PP |
1898 | \fIExamples\fR |
1898 | \fIExamples\fR |
1899 | .IX Subsection "Examples" |
1899 | .IX Subsection "Examples" |
1900 | .PP |
1900 | .PP |
1901 | Example: Watch \f(CW\*(C`/etc/passwd\*(C'\fR for attribute changes. |
1901 | Example: Watch \f(CW\*(C`/etc/passwd\*(C'\fR for attribute changes. |
1902 | .PP |
1902 | .PP |
1903 | .Vb 10 |
1903 | .Vb 10 |
1904 | \& static void |
1904 | \& static void |
1905 | \& passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
1905 | \& passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
1906 | \& { |
1906 | \& { |
1907 | \& /* /etc/passwd changed in some way */ |
1907 | \& /* /etc/passwd changed in some way */ |
1908 | \& if (w\->attr.st_nlink) |
1908 | \& if (w\->attr.st_nlink) |
1909 | \& { |
1909 | \& { |
1910 | \& printf ("passwd current size %ld\en", (long)w\->attr.st_size); |
1910 | \& printf ("passwd current size %ld\en", (long)w\->attr.st_size); |
1911 | \& printf ("passwd current atime %ld\en", (long)w\->attr.st_mtime); |
1911 | \& printf ("passwd current atime %ld\en", (long)w\->attr.st_mtime); |
1912 | \& printf ("passwd current mtime %ld\en", (long)w\->attr.st_mtime); |
1912 | \& printf ("passwd current mtime %ld\en", (long)w\->attr.st_mtime); |
1913 | \& } |
1913 | \& } |
1914 | \& else |
1914 | \& else |
1915 | \& /* you shalt not abuse printf for puts */ |
1915 | \& /* you shalt not abuse printf for puts */ |
1916 | \& puts ("wow, /etc/passwd is not there, expect problems. " |
1916 | \& puts ("wow, /etc/passwd is not there, expect problems. " |
1917 | \& "if this is windows, they already arrived\en"); |
1917 | \& "if this is windows, they already arrived\en"); |
1918 | \& } |
1918 | \& } |
1919 | \& |
1919 | \& |
1920 | \& ... |
1920 | \& ... |
1921 | \& ev_stat passwd; |
1921 | \& ev_stat passwd; |
1922 | \& |
1922 | \& |
1923 | \& ev_stat_init (&passwd, passwd_cb, "/etc/passwd", 0.); |
1923 | \& ev_stat_init (&passwd, passwd_cb, "/etc/passwd", 0.); |
1924 | \& ev_stat_start (loop, &passwd); |
1924 | \& ev_stat_start (loop, &passwd); |
1925 | .Ve |
1925 | .Ve |
1926 | .PP |
1926 | .PP |
1927 | Example: Like above, but additionally use a one-second delay so we do not |
1927 | Example: Like above, but additionally use a one-second delay so we do not |
1928 | miss updates (however, frequent updates will delay processing, too, so |
1928 | miss updates (however, frequent updates will delay processing, too, so |
1929 | one might do the work both on \f(CW\*(C`ev_stat\*(C'\fR callback invocation \fIand\fR on |
1929 | one might do the work both on \f(CW\*(C`ev_stat\*(C'\fR callback invocation \fIand\fR on |
1930 | \&\f(CW\*(C`ev_timer\*(C'\fR callback invocation). |
1930 | \&\f(CW\*(C`ev_timer\*(C'\fR callback invocation). |
1931 | .PP |
1931 | .PP |
1932 | .Vb 2 |
1932 | .Vb 2 |
1933 | \& static ev_stat passwd; |
1933 | \& static ev_stat passwd; |
1934 | \& static ev_timer timer; |
1934 | \& static ev_timer timer; |
1935 | \& |
1935 | \& |
1936 | \& static void |
1936 | \& static void |
1937 | \& timer_cb (EV_P_ ev_timer *w, int revents) |
1937 | \& timer_cb (EV_P_ ev_timer *w, int revents) |
1938 | \& { |
1938 | \& { |
1939 | \& ev_timer_stop (EV_A_ w); |
1939 | \& ev_timer_stop (EV_A_ w); |
1940 | \& |
1940 | \& |
1941 | \& /* now it\*(Aqs one second after the most recent passwd change */ |
1941 | \& /* now it\*(Aqs one second after the most recent passwd change */ |
1942 | \& } |
1942 | \& } |
1943 | \& |
1943 | \& |
1944 | \& static void |
1944 | \& static void |
1945 | \& stat_cb (EV_P_ ev_stat *w, int revents) |
1945 | \& stat_cb (EV_P_ ev_stat *w, int revents) |
1946 | \& { |
1946 | \& { |
1947 | \& /* reset the one\-second timer */ |
1947 | \& /* reset the one\-second timer */ |
1948 | \& ev_timer_again (EV_A_ &timer); |
1948 | \& ev_timer_again (EV_A_ &timer); |
1949 | \& } |
1949 | \& } |
1950 | \& |
1950 | \& |
1951 | \& ... |
1951 | \& ... |
1952 | \& ev_stat_init (&passwd, stat_cb, "/etc/passwd", 0.); |
1952 | \& ev_stat_init (&passwd, stat_cb, "/etc/passwd", 0.); |
1953 | \& ev_stat_start (loop, &passwd); |
1953 | \& ev_stat_start (loop, &passwd); |
1954 | \& ev_timer_init (&timer, timer_cb, 0., 1.02); |
1954 | \& ev_timer_init (&timer, timer_cb, 0., 1.02); |
1955 | .Ve |
1955 | .Ve |
1956 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
1956 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
1957 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." |
1957 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." |
1958 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
1958 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
1959 | Idle watchers trigger events when no other events of the same or higher |
1959 | Idle watchers trigger events when no other events of the same or higher |
… | |
… | |
1988 | .PP |
1988 | .PP |
1989 | Example: Dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR watcher, start it, and in the |
1989 | Example: Dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR watcher, start it, and in the |
1990 | callback, free it. Also, use no error checking, as usual. |
1990 | callback, free it. Also, use no error checking, as usual. |
1991 | .PP |
1991 | .PP |
1992 | .Vb 7 |
1992 | .Vb 7 |
1993 | \& static void |
1993 | \& static void |
1994 | \& idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1994 | \& idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1995 | \& { |
1995 | \& { |
1996 | \& free (w); |
1996 | \& free (w); |
1997 | \& // now do something you wanted to do when the program has |
1997 | \& // now do something you wanted to do when the program has |
1998 | \& // no longer anything immediate to do. |
1998 | \& // no longer anything immediate to do. |
1999 | \& } |
1999 | \& } |
2000 | \& |
2000 | \& |
2001 | \& struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle)); |
2001 | \& struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle)); |
2002 | \& ev_idle_init (idle_watcher, idle_cb); |
2002 | \& ev_idle_init (idle_watcher, idle_cb); |
2003 | \& ev_idle_start (loop, idle_cb); |
2003 | \& ev_idle_start (loop, idle_cb); |
2004 | .Ve |
2004 | .Ve |
2005 | .ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop!" |
2005 | .ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop!" |
2006 | .el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop!" |
2006 | .el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop!" |
2007 | .IX Subsection "ev_prepare and ev_check - customise your event loop!" |
2007 | .IX Subsection "ev_prepare and ev_check - customise your event loop!" |
2008 | Prepare and check watchers are usually (but not always) used in tandem: |
2008 | Prepare and check watchers are usually (but not always) used in tandem: |
… | |
… | |
2027 | .PP |
2027 | .PP |
2028 | This is done by examining in each prepare call which file descriptors need |
2028 | This is done by examining in each prepare call which file descriptors need |
2029 | to be watched by the other library, registering \f(CW\*(C`ev_io\*(C'\fR watchers for |
2029 | to be watched by the other library, registering \f(CW\*(C`ev_io\*(C'\fR watchers for |
2030 | them and starting an \f(CW\*(C`ev_timer\*(C'\fR watcher for any timeouts (many libraries |
2030 | them and starting an \f(CW\*(C`ev_timer\*(C'\fR watcher for any timeouts (many libraries |
2031 | provide just this functionality). Then, in the check watcher you check for |
2031 | provide just this functionality). Then, in the check watcher you check for |
2032 | any events that occured (by checking the pending status of all watchers |
2032 | any events that occurred (by checking the pending status of all watchers |
2033 | and stopping them) and call back into the library. The I/O and timer |
2033 | and stopping them) and call back into the library. The I/O and timer |
2034 | callbacks will never actually be called (but must be valid nevertheless, |
2034 | callbacks will never actually be called (but must be valid nevertheless, |
2035 | because you never know, you know?). |
2035 | because you never know, you know?). |
2036 | .PP |
2036 | .PP |
2037 | As another example, the Perl Coro module uses these hooks to integrate |
2037 | As another example, the Perl Coro module uses these hooks to integrate |
… | |
… | |
2080 | is pseudo-code only of course. This requires you to either use a low |
2080 | is pseudo-code only of course. This requires you to either use a low |
2081 | priority for the check watcher or use \f(CW\*(C`ev_clear_pending\*(C'\fR explicitly, as |
2081 | priority for the check watcher or use \f(CW\*(C`ev_clear_pending\*(C'\fR explicitly, as |
2082 | the callbacks for the IO/timeout watchers might not have been called yet. |
2082 | the callbacks for the IO/timeout watchers might not have been called yet. |
2083 | .PP |
2083 | .PP |
2084 | .Vb 2 |
2084 | .Vb 2 |
2085 | \& static ev_io iow [nfd]; |
2085 | \& static ev_io iow [nfd]; |
2086 | \& static ev_timer tw; |
2086 | \& static ev_timer tw; |
2087 | \& |
2087 | \& |
2088 | \& static void |
2088 | \& static void |
2089 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
2089 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
2090 | \& { |
2090 | \& { |
2091 | \& } |
2091 | \& } |
2092 | \& |
2092 | \& |
2093 | \& // create io watchers for each fd and a timer before blocking |
2093 | \& // create io watchers for each fd and a timer before blocking |
2094 | \& static void |
2094 | \& static void |
2095 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
2095 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
2096 | \& { |
2096 | \& { |
2097 | \& int timeout = 3600000; |
2097 | \& int timeout = 3600000; |
2098 | \& struct pollfd fds [nfd]; |
2098 | \& struct pollfd fds [nfd]; |
2099 | \& // actual code will need to loop here and realloc etc. |
2099 | \& // actual code will need to loop here and realloc etc. |
2100 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
2100 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
2101 | \& |
2101 | \& |
2102 | \& /* the callback is illegal, but won\*(Aqt be called as we stop during check */ |
2102 | \& /* the callback is illegal, but won\*(Aqt be called as we stop during check */ |
2103 | \& ev_timer_init (&tw, 0, timeout * 1e\-3); |
2103 | \& ev_timer_init (&tw, 0, timeout * 1e\-3); |
2104 | \& ev_timer_start (loop, &tw); |
2104 | \& ev_timer_start (loop, &tw); |
2105 | \& |
2105 | \& |
2106 | \& // create one ev_io per pollfd |
2106 | \& // create one ev_io per pollfd |
2107 | \& for (int i = 0; i < nfd; ++i) |
2107 | \& for (int i = 0; i < nfd; ++i) |
2108 | \& { |
2108 | \& { |
2109 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
2109 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
2110 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
2110 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
2111 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
2111 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
2112 | \& |
2112 | \& |
2113 | \& fds [i].revents = 0; |
2113 | \& fds [i].revents = 0; |
2114 | \& ev_io_start (loop, iow + i); |
2114 | \& ev_io_start (loop, iow + i); |
2115 | \& } |
2115 | \& } |
2116 | \& } |
2116 | \& } |
2117 | \& |
2117 | \& |
2118 | \& // stop all watchers after blocking |
2118 | \& // stop all watchers after blocking |
2119 | \& static void |
2119 | \& static void |
2120 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
2120 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
2121 | \& { |
2121 | \& { |
2122 | \& ev_timer_stop (loop, &tw); |
2122 | \& ev_timer_stop (loop, &tw); |
2123 | \& |
2123 | \& |
2124 | \& for (int i = 0; i < nfd; ++i) |
2124 | \& for (int i = 0; i < nfd; ++i) |
2125 | \& { |
2125 | \& { |
2126 | \& // set the relevant poll flags |
2126 | \& // set the relevant poll flags |
2127 | \& // could also call adns_processreadable etc. here |
2127 | \& // could also call adns_processreadable etc. here |
2128 | \& struct pollfd *fd = fds + i; |
2128 | \& struct pollfd *fd = fds + i; |
2129 | \& int revents = ev_clear_pending (iow + i); |
2129 | \& int revents = ev_clear_pending (iow + i); |
2130 | \& if (revents & EV_READ ) fd\->revents |= fd\->events & POLLIN; |
2130 | \& if (revents & EV_READ ) fd\->revents |= fd\->events & POLLIN; |
2131 | \& if (revents & EV_WRITE) fd\->revents |= fd\->events & POLLOUT; |
2131 | \& if (revents & EV_WRITE) fd\->revents |= fd\->events & POLLOUT; |
2132 | \& |
2132 | \& |
2133 | \& // now stop the watcher |
2133 | \& // now stop the watcher |
2134 | \& ev_io_stop (loop, iow + i); |
2134 | \& ev_io_stop (loop, iow + i); |
2135 | \& } |
2135 | \& } |
2136 | \& |
2136 | \& |
2137 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
2137 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
2138 | \& } |
2138 | \& } |
2139 | .Ve |
2139 | .Ve |
2140 | .PP |
2140 | .PP |
2141 | Method 2: This would be just like method 1, but you run \f(CW\*(C`adns_afterpoll\*(C'\fR |
2141 | Method 2: This would be just like method 1, but you run \f(CW\*(C`adns_afterpoll\*(C'\fR |
2142 | in the prepare watcher and would dispose of the check watcher. |
2142 | in the prepare watcher and would dispose of the check watcher. |
2143 | .PP |
2143 | .PP |
2144 | Method 3: If the module to be embedded supports explicit event |
2144 | Method 3: If the module to be embedded supports explicit event |
2145 | notification (adns does), you can also make use of the actual watcher |
2145 | notification (libadns does), you can also make use of the actual watcher |
2146 | callbacks, and only destroy/create the watchers in the prepare watcher. |
2146 | callbacks, and only destroy/create the watchers in the prepare watcher. |
2147 | .PP |
2147 | .PP |
2148 | .Vb 5 |
2148 | .Vb 5 |
2149 | \& static void |
2149 | \& static void |
2150 | \& timer_cb (EV_P_ ev_timer *w, int revents) |
2150 | \& timer_cb (EV_P_ ev_timer *w, int revents) |
2151 | \& { |
2151 | \& { |
2152 | \& adns_state ads = (adns_state)w\->data; |
2152 | \& adns_state ads = (adns_state)w\->data; |
2153 | \& update_now (EV_A); |
2153 | \& update_now (EV_A); |
2154 | \& |
2154 | \& |
2155 | \& adns_processtimeouts (ads, &tv_now); |
2155 | \& adns_processtimeouts (ads, &tv_now); |
2156 | \& } |
2156 | \& } |
2157 | \& |
2157 | \& |
2158 | \& static void |
2158 | \& static void |
2159 | \& io_cb (EV_P_ ev_io *w, int revents) |
2159 | \& io_cb (EV_P_ ev_io *w, int revents) |
2160 | \& { |
2160 | \& { |
2161 | \& adns_state ads = (adns_state)w\->data; |
2161 | \& adns_state ads = (adns_state)w\->data; |
2162 | \& update_now (EV_A); |
2162 | \& update_now (EV_A); |
2163 | \& |
2163 | \& |
2164 | \& if (revents & EV_READ ) adns_processreadable (ads, w\->fd, &tv_now); |
2164 | \& if (revents & EV_READ ) adns_processreadable (ads, w\->fd, &tv_now); |
2165 | \& if (revents & EV_WRITE) adns_processwriteable (ads, w\->fd, &tv_now); |
2165 | \& if (revents & EV_WRITE) adns_processwriteable (ads, w\->fd, &tv_now); |
2166 | \& } |
2166 | \& } |
2167 | \& |
2167 | \& |
2168 | \& // do not ever call adns_afterpoll |
2168 | \& // do not ever call adns_afterpoll |
2169 | .Ve |
2169 | .Ve |
2170 | .PP |
2170 | .PP |
2171 | Method 4: Do not use a prepare or check watcher because the module you |
2171 | Method 4: Do not use a prepare or check watcher because the module you |
2172 | want to embed is too inflexible to support it. Instead, youc na override |
2172 | want to embed is too inflexible to support it. Instead, you can override |
2173 | their poll function. The drawback with this solution is that the main |
2173 | their poll function. The drawback with this solution is that the main |
2174 | loop is now no longer controllable by \s-1EV\s0. The \f(CW\*(C`Glib::EV\*(C'\fR module does |
2174 | loop is now no longer controllable by \s-1EV\s0. The \f(CW\*(C`Glib::EV\*(C'\fR module does |
2175 | this. |
2175 | this. |
2176 | .PP |
2176 | .PP |
2177 | .Vb 4 |
2177 | .Vb 4 |
2178 | \& static gint |
2178 | \& static gint |
2179 | \& event_poll_func (GPollFD *fds, guint nfds, gint timeout) |
2179 | \& event_poll_func (GPollFD *fds, guint nfds, gint timeout) |
2180 | \& { |
2180 | \& { |
2181 | \& int got_events = 0; |
2181 | \& int got_events = 0; |
2182 | \& |
2182 | \& |
2183 | \& for (n = 0; n < nfds; ++n) |
2183 | \& for (n = 0; n < nfds; ++n) |
2184 | \& // create/start io watcher that sets the relevant bits in fds[n] and increment got_events |
2184 | \& // create/start io watcher that sets the relevant bits in fds[n] and increment got_events |
2185 | \& |
2185 | \& |
2186 | \& if (timeout >= 0) |
2186 | \& if (timeout >= 0) |
2187 | \& // create/start timer |
2187 | \& // create/start timer |
2188 | \& |
2188 | \& |
2189 | \& // poll |
2189 | \& // poll |
2190 | \& ev_loop (EV_A_ 0); |
2190 | \& ev_loop (EV_A_ 0); |
2191 | \& |
2191 | \& |
2192 | \& // stop timer again |
2192 | \& // stop timer again |
2193 | \& if (timeout >= 0) |
2193 | \& if (timeout >= 0) |
2194 | \& ev_timer_stop (EV_A_ &to); |
2194 | \& ev_timer_stop (EV_A_ &to); |
2195 | \& |
2195 | \& |
2196 | \& // stop io watchers again \- their callbacks should have set |
2196 | \& // stop io watchers again \- their callbacks should have set |
2197 | \& for (n = 0; n < nfds; ++n) |
2197 | \& for (n = 0; n < nfds; ++n) |
2198 | \& ev_io_stop (EV_A_ iow [n]); |
2198 | \& ev_io_stop (EV_A_ iow [n]); |
2199 | \& |
2199 | \& |
2200 | \& return got_events; |
2200 | \& return got_events; |
2201 | \& } |
2201 | \& } |
2202 | .Ve |
2202 | .Ve |
2203 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
2203 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
2204 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
2204 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
2205 | .IX Subsection "ev_embed - when one backend isn't enough..." |
2205 | .IX Subsection "ev_embed - when one backend isn't enough..." |
2206 | This is a rather advanced watcher type that lets you embed one event loop |
2206 | This is a rather advanced watcher type that lets you embed one event loop |
… | |
… | |
2262 | .PD |
2262 | .PD |
2263 | Configures the watcher to embed the given loop, which must be |
2263 | Configures the watcher to embed the given loop, which must be |
2264 | embeddable. If the callback is \f(CW0\fR, then \f(CW\*(C`ev_embed_sweep\*(C'\fR will be |
2264 | embeddable. If the callback is \f(CW0\fR, then \f(CW\*(C`ev_embed_sweep\*(C'\fR will be |
2265 | invoked automatically, otherwise it is the responsibility of the callback |
2265 | invoked automatically, otherwise it is the responsibility of the callback |
2266 | to invoke it (it will continue to be called until the sweep has been done, |
2266 | to invoke it (it will continue to be called until the sweep has been done, |
2267 | if you do not want thta, you need to temporarily stop the embed watcher). |
2267 | if you do not want that, you need to temporarily stop the embed watcher). |
2268 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
2268 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
2269 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
2269 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
2270 | Make a single, non-blocking sweep over the embedded loop. This works |
2270 | Make a single, non-blocking sweep over the embedded loop. This works |
2271 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
2271 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
2272 | apropriate way for embedded loops. |
2272 | appropriate way for embedded loops. |
2273 | .IP "struct ev_loop *other [read\-only]" 4 |
2273 | .IP "struct ev_loop *other [read\-only]" 4 |
2274 | .IX Item "struct ev_loop *other [read-only]" |
2274 | .IX Item "struct ev_loop *other [read-only]" |
2275 | The embedded event loop. |
2275 | The embedded event loop. |
2276 | .PP |
2276 | .PP |
2277 | \fIExamples\fR |
2277 | \fIExamples\fR |
2278 | .IX Subsection "Examples" |
2278 | .IX Subsection "Examples" |
2279 | .PP |
2279 | .PP |
2280 | Example: Try to get an embeddable event loop and embed it into the default |
2280 | Example: Try to get an embeddable event loop and embed it into the default |
2281 | event loop. If that is not possible, use the default loop. The default |
2281 | event loop. If that is not possible, use the default loop. The default |
2282 | loop is stored in \f(CW\*(C`loop_hi\*(C'\fR, while the mebeddable loop is stored in |
2282 | loop is stored in \f(CW\*(C`loop_hi\*(C'\fR, while the embeddable loop is stored in |
2283 | \&\f(CW\*(C`loop_lo\*(C'\fR (which is \f(CW\*(C`loop_hi\*(C'\fR in the acse no embeddable loop can be |
2283 | \&\f(CW\*(C`loop_lo\*(C'\fR (which is \f(CW\*(C`loop_hi\*(C'\fR in the case no embeddable loop can be |
2284 | used). |
2284 | used). |
2285 | .PP |
2285 | .PP |
2286 | .Vb 3 |
2286 | .Vb 3 |
2287 | \& struct ev_loop *loop_hi = ev_default_init (0); |
2287 | \& struct ev_loop *loop_hi = ev_default_init (0); |
2288 | \& struct ev_loop *loop_lo = 0; |
2288 | \& struct ev_loop *loop_lo = 0; |
2289 | \& struct ev_embed embed; |
2289 | \& struct ev_embed embed; |
2290 | \& |
2290 | \& |
2291 | \& // see if there is a chance of getting one that works |
2291 | \& // see if there is a chance of getting one that works |
2292 | \& // (remember that a flags value of 0 means autodetection) |
2292 | \& // (remember that a flags value of 0 means autodetection) |
2293 | \& loop_lo = ev_embeddable_backends () & ev_recommended_backends () |
2293 | \& loop_lo = ev_embeddable_backends () & ev_recommended_backends () |
2294 | \& ? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ()) |
2294 | \& ? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ()) |
2295 | \& : 0; |
2295 | \& : 0; |
2296 | \& |
2296 | \& |
2297 | \& // if we got one, then embed it, otherwise default to loop_hi |
2297 | \& // if we got one, then embed it, otherwise default to loop_hi |
2298 | \& if (loop_lo) |
2298 | \& if (loop_lo) |
2299 | \& { |
2299 | \& { |
2300 | \& ev_embed_init (&embed, 0, loop_lo); |
2300 | \& ev_embed_init (&embed, 0, loop_lo); |
2301 | \& ev_embed_start (loop_hi, &embed); |
2301 | \& ev_embed_start (loop_hi, &embed); |
2302 | \& } |
2302 | \& } |
2303 | \& else |
2303 | \& else |
2304 | \& loop_lo = loop_hi; |
2304 | \& loop_lo = loop_hi; |
2305 | .Ve |
2305 | .Ve |
2306 | .PP |
2306 | .PP |
2307 | Example: Check if kqueue is available but not recommended and create |
2307 | Example: Check if kqueue is available but not recommended and create |
2308 | a kqueue backend for use with sockets (which usually work with any |
2308 | a kqueue backend for use with sockets (which usually work with any |
2309 | kqueue implementation). Store the kqueue/socket\-only event loop in |
2309 | kqueue implementation). Store the kqueue/socket\-only event loop in |
2310 | \&\f(CW\*(C`loop_socket\*(C'\fR. (One might optionally use \f(CW\*(C`EVFLAG_NOENV\*(C'\fR, too). |
2310 | \&\f(CW\*(C`loop_socket\*(C'\fR. (One might optionally use \f(CW\*(C`EVFLAG_NOENV\*(C'\fR, too). |
2311 | .PP |
2311 | .PP |
2312 | .Vb 3 |
2312 | .Vb 3 |
2313 | \& struct ev_loop *loop = ev_default_init (0); |
2313 | \& struct ev_loop *loop = ev_default_init (0); |
2314 | \& struct ev_loop *loop_socket = 0; |
2314 | \& struct ev_loop *loop_socket = 0; |
2315 | \& struct ev_embed embed; |
2315 | \& struct ev_embed embed; |
2316 | \& |
2316 | \& |
2317 | \& if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE) |
2317 | \& if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE) |
2318 | \& if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE)) |
2318 | \& if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE)) |
2319 | \& { |
2319 | \& { |
2320 | \& ev_embed_init (&embed, 0, loop_socket); |
2320 | \& ev_embed_init (&embed, 0, loop_socket); |
2321 | \& ev_embed_start (loop, &embed); |
2321 | \& ev_embed_start (loop, &embed); |
2322 | \& } |
2322 | \& } |
2323 | \& |
2323 | \& |
2324 | \& if (!loop_socket) |
2324 | \& if (!loop_socket) |
2325 | \& loop_socket = loop; |
2325 | \& loop_socket = loop; |
2326 | \& |
2326 | \& |
2327 | \& // now use loop_socket for all sockets, and loop for everything else |
2327 | \& // now use loop_socket for all sockets, and loop for everything else |
2328 | .Ve |
2328 | .Ve |
2329 | .ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork" |
2329 | .ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork" |
2330 | .el .Sh "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork" |
2330 | .el .Sh "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork" |
2331 | .IX Subsection "ev_fork - the audacity to resume the event loop after a fork" |
2331 | .IX Subsection "ev_fork - the audacity to resume the event loop after a fork" |
2332 | Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because |
2332 | Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because |
… | |
… | |
2378 | queue: |
2378 | queue: |
2379 | .IP "queueing from a signal handler context" 4 |
2379 | .IP "queueing from a signal handler context" 4 |
2380 | .IX Item "queueing from a signal handler context" |
2380 | .IX Item "queueing from a signal handler context" |
2381 | To implement race-free queueing, you simply add to the queue in the signal |
2381 | To implement race-free queueing, you simply add to the queue in the signal |
2382 | handler but you block the signal handler in the watcher callback. Here is an example that does that for |
2382 | handler but you block the signal handler in the watcher callback. Here is an example that does that for |
2383 | some fictitiuous \s-1SIGUSR1\s0 handler: |
2383 | some fictitious \s-1SIGUSR1\s0 handler: |
2384 | .Sp |
2384 | .Sp |
2385 | .Vb 1 |
2385 | .Vb 1 |
2386 | \& static ev_async mysig; |
2386 | \& static ev_async mysig; |
2387 | \& |
2387 | \& |
2388 | \& static void |
2388 | \& static void |
… | |
… | |
2459 | .IP "ev_async_send (loop, ev_async *)" 4 |
2459 | .IP "ev_async_send (loop, ev_async *)" 4 |
2460 | .IX Item "ev_async_send (loop, ev_async *)" |
2460 | .IX Item "ev_async_send (loop, ev_async *)" |
2461 | Sends/signals/activates the given \f(CW\*(C`ev_async\*(C'\fR watcher, that is, feeds |
2461 | Sends/signals/activates the given \f(CW\*(C`ev_async\*(C'\fR watcher, that is, feeds |
2462 | an \f(CW\*(C`EV_ASYNC\*(C'\fR event on the watcher into the event loop. Unlike |
2462 | an \f(CW\*(C`EV_ASYNC\*(C'\fR event on the watcher into the event loop. Unlike |
2463 | \&\f(CW\*(C`ev_feed_event\*(C'\fR, this call is safe to do in other threads, signal or |
2463 | \&\f(CW\*(C`ev_feed_event\*(C'\fR, this call is safe to do in other threads, signal or |
2464 | similar contexts (see the dicusssion of \f(CW\*(C`EV_ATOMIC_T\*(C'\fR in the embedding |
2464 | similar contexts (see the discussion of \f(CW\*(C`EV_ATOMIC_T\*(C'\fR in the embedding |
2465 | section below on what exactly this means). |
2465 | section below on what exactly this means). |
2466 | .Sp |
2466 | .Sp |
2467 | This call incurs the overhead of a syscall only once per loop iteration, |
2467 | This call incurs the overhead of a system call only once per loop iteration, |
2468 | so while the overhead might be noticable, it doesn't apply to repeated |
2468 | so while the overhead might be noticeable, it doesn't apply to repeated |
2469 | calls to \f(CW\*(C`ev_async_send\*(C'\fR. |
2469 | calls to \f(CW\*(C`ev_async_send\*(C'\fR. |
2470 | .IP "bool = ev_async_pending (ev_async *)" 4 |
2470 | .IP "bool = ev_async_pending (ev_async *)" 4 |
2471 | .IX Item "bool = ev_async_pending (ev_async *)" |
2471 | .IX Item "bool = ev_async_pending (ev_async *)" |
2472 | Returns a non-zero value when \f(CW\*(C`ev_async_send\*(C'\fR has been called on the |
2472 | Returns a non-zero value when \f(CW\*(C`ev_async_send\*(C'\fR has been called on the |
2473 | watcher but the event has not yet been processed (or even noted) by the |
2473 | watcher but the event has not yet been processed (or even noted) by the |
2474 | event loop. |
2474 | event loop. |
2475 | .Sp |
2475 | .Sp |
2476 | \&\f(CW\*(C`ev_async_send\*(C'\fR sets a flag in the watcher and wakes up the loop. When |
2476 | \&\f(CW\*(C`ev_async_send\*(C'\fR sets a flag in the watcher and wakes up the loop. When |
2477 | the loop iterates next and checks for the watcher to have become active, |
2477 | the loop iterates next and checks for the watcher to have become active, |
2478 | it will reset the flag again. \f(CW\*(C`ev_async_pending\*(C'\fR can be used to very |
2478 | it will reset the flag again. \f(CW\*(C`ev_async_pending\*(C'\fR can be used to very |
2479 | quickly check wether invoking the loop might be a good idea. |
2479 | quickly check whether invoking the loop might be a good idea. |
2480 | .Sp |
2480 | .Sp |
2481 | Not that this does \fInot\fR check wether the watcher itself is pending, only |
2481 | Not that this does \fInot\fR check whether the watcher itself is pending, only |
2482 | wether it has been requested to make this watcher pending. |
2482 | whether it has been requested to make this watcher pending. |
2483 | .SH "OTHER FUNCTIONS" |
2483 | .SH "OTHER FUNCTIONS" |
2484 | .IX Header "OTHER FUNCTIONS" |
2484 | .IX Header "OTHER FUNCTIONS" |
2485 | There are some other functions of possible interest. Described. Here. Now. |
2485 | There are some other functions of possible interest. Described. Here. Now. |
2486 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
2486 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
2487 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
2487 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
… | |
… | |
2491 | or timeout without having to allocate/configure/start/stop/free one or |
2491 | or timeout without having to allocate/configure/start/stop/free one or |
2492 | more watchers yourself. |
2492 | more watchers yourself. |
2493 | .Sp |
2493 | .Sp |
2494 | If \f(CW\*(C`fd\*(C'\fR is less than 0, then no I/O watcher will be started and events |
2494 | If \f(CW\*(C`fd\*(C'\fR is less than 0, then no I/O watcher will be started and events |
2495 | is being ignored. Otherwise, an \f(CW\*(C`ev_io\*(C'\fR watcher for the given \f(CW\*(C`fd\*(C'\fR and |
2495 | is being ignored. Otherwise, an \f(CW\*(C`ev_io\*(C'\fR watcher for the given \f(CW\*(C`fd\*(C'\fR and |
2496 | \&\f(CW\*(C`events\*(C'\fR set will be craeted and started. |
2496 | \&\f(CW\*(C`events\*(C'\fR set will be created and started. |
2497 | .Sp |
2497 | .Sp |
2498 | If \f(CW\*(C`timeout\*(C'\fR is less than 0, then no timeout watcher will be |
2498 | If \f(CW\*(C`timeout\*(C'\fR is less than 0, then no timeout watcher will be |
2499 | started. Otherwise an \f(CW\*(C`ev_timer\*(C'\fR watcher with after = \f(CW\*(C`timeout\*(C'\fR (and |
2499 | started. Otherwise an \f(CW\*(C`ev_timer\*(C'\fR watcher with after = \f(CW\*(C`timeout\*(C'\fR (and |
2500 | repeat = 0) will be started. While \f(CW0\fR is a valid timeout, it is of |
2500 | repeat = 0) will be started. While \f(CW0\fR is a valid timeout, it is of |
2501 | dubious value. |
2501 | dubious value. |
… | |
… | |
2504 | passed an \f(CW\*(C`revents\*(C'\fR set like normal event callbacks (a combination of |
2504 | passed an \f(CW\*(C`revents\*(C'\fR set like normal event callbacks (a combination of |
2505 | \&\f(CW\*(C`EV_ERROR\*(C'\fR, \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or \f(CW\*(C`EV_TIMEOUT\*(C'\fR) and the \f(CW\*(C`arg\*(C'\fR |
2505 | \&\f(CW\*(C`EV_ERROR\*(C'\fR, \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or \f(CW\*(C`EV_TIMEOUT\*(C'\fR) and the \f(CW\*(C`arg\*(C'\fR |
2506 | value passed to \f(CW\*(C`ev_once\*(C'\fR: |
2506 | value passed to \f(CW\*(C`ev_once\*(C'\fR: |
2507 | .Sp |
2507 | .Sp |
2508 | .Vb 7 |
2508 | .Vb 7 |
2509 | \& static void stdin_ready (int revents, void *arg) |
2509 | \& static void stdin_ready (int revents, void *arg) |
2510 | \& { |
2510 | \& { |
2511 | \& if (revents & EV_TIMEOUT) |
2511 | \& if (revents & EV_TIMEOUT) |
2512 | \& /* doh, nothing entered */; |
2512 | \& /* doh, nothing entered */; |
2513 | \& else if (revents & EV_READ) |
2513 | \& else if (revents & EV_READ) |
2514 | \& /* stdin might have data for us, joy! */; |
2514 | \& /* stdin might have data for us, joy! */; |
2515 | \& } |
2515 | \& } |
2516 | \& |
2516 | \& |
2517 | \& ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); |
2517 | \& ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); |
2518 | .Ve |
2518 | .Ve |
2519 | .IP "ev_feed_event (ev_loop *, watcher *, int revents)" 4 |
2519 | .IP "ev_feed_event (ev_loop *, watcher *, int revents)" 4 |
2520 | .IX Item "ev_feed_event (ev_loop *, watcher *, int revents)" |
2520 | .IX Item "ev_feed_event (ev_loop *, watcher *, int revents)" |
2521 | Feeds the given event set into the event loop, as if the specified event |
2521 | Feeds the given event set into the event loop, as if the specified event |
2522 | had happened for the specified watcher (which must be a pointer to an |
2522 | had happened for the specified watcher (which must be a pointer to an |
… | |
… | |
2525 | .IX Item "ev_feed_fd_event (ev_loop *, int fd, int revents)" |
2525 | .IX Item "ev_feed_fd_event (ev_loop *, int fd, int revents)" |
2526 | Feed an event on the given fd, as if a file descriptor backend detected |
2526 | Feed an event on the given fd, as if a file descriptor backend detected |
2527 | the given events it. |
2527 | the given events it. |
2528 | .IP "ev_feed_signal_event (ev_loop *loop, int signum)" 4 |
2528 | .IP "ev_feed_signal_event (ev_loop *loop, int signum)" 4 |
2529 | .IX Item "ev_feed_signal_event (ev_loop *loop, int signum)" |
2529 | .IX Item "ev_feed_signal_event (ev_loop *loop, int signum)" |
2530 | Feed an event as if the given signal occured (\f(CW\*(C`loop\*(C'\fR must be the default |
2530 | Feed an event as if the given signal occurred (\f(CW\*(C`loop\*(C'\fR must be the default |
2531 | loop!). |
2531 | loop!). |
2532 | .SH "LIBEVENT EMULATION" |
2532 | .SH "LIBEVENT EMULATION" |
2533 | .IX Header "LIBEVENT EMULATION" |
2533 | .IX Header "LIBEVENT EMULATION" |
2534 | Libev offers a compatibility emulation layer for libevent. It cannot |
2534 | Libev offers a compatibility emulation layer for libevent. It cannot |
2535 | emulate the internals of libevent, so here are some usage hints: |
2535 | emulate the internals of libevent, so here are some usage hints: |
… | |
… | |
2555 | The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need |
2555 | The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need |
2556 | to use the libev header file and library. |
2556 | to use the libev header file and library. |
2557 | .SH "\*(C+ SUPPORT" |
2557 | .SH "\*(C+ SUPPORT" |
2558 | .IX Header " SUPPORT" |
2558 | .IX Header " SUPPORT" |
2559 | Libev comes with some simplistic wrapper classes for \*(C+ that mainly allow |
2559 | Libev comes with some simplistic wrapper classes for \*(C+ that mainly allow |
2560 | you to use some convinience methods to start/stop watchers and also change |
2560 | you to use some convenience methods to start/stop watchers and also change |
2561 | the callback model to a model using method callbacks on objects. |
2561 | the callback model to a model using method callbacks on objects. |
2562 | .PP |
2562 | .PP |
2563 | To use it, |
2563 | To use it, |
2564 | .PP |
2564 | .PP |
2565 | .Vb 1 |
2565 | .Vb 1 |
2566 | \& #include <ev++.h> |
2566 | \& #include <ev++.h> |
2567 | .Ve |
2567 | .Ve |
2568 | .PP |
2568 | .PP |
2569 | This automatically includes \fIev.h\fR and puts all of its definitions (many |
2569 | This automatically includes \fIev.h\fR and puts all of its definitions (many |
2570 | of them macros) into the global namespace. All \*(C+ specific things are |
2570 | of them macros) into the global namespace. All \*(C+ specific things are |
2571 | put into the \f(CW\*(C`ev\*(C'\fR namespace. It should support all the same embedding |
2571 | put into the \f(CW\*(C`ev\*(C'\fR namespace. It should support all the same embedding |
… | |
… | |
2637 | thunking function, making it as fast as a direct C callback. |
2637 | thunking function, making it as fast as a direct C callback. |
2638 | .Sp |
2638 | .Sp |
2639 | Example: simple class declaration and watcher initialisation |
2639 | Example: simple class declaration and watcher initialisation |
2640 | .Sp |
2640 | .Sp |
2641 | .Vb 4 |
2641 | .Vb 4 |
2642 | \& struct myclass |
2642 | \& struct myclass |
2643 | \& { |
2643 | \& { |
2644 | \& void io_cb (ev::io &w, int revents) { } |
2644 | \& void io_cb (ev::io &w, int revents) { } |
2645 | \& } |
2645 | \& } |
2646 | \& |
2646 | \& |
2647 | \& myclass obj; |
2647 | \& myclass obj; |
2648 | \& ev::io iow; |
2648 | \& ev::io iow; |
2649 | \& iow.set <myclass, &myclass::io_cb> (&obj); |
2649 | \& iow.set <myclass, &myclass::io_cb> (&obj); |
2650 | .Ve |
2650 | .Ve |
2651 | .IP "w\->set<function> (void *data = 0)" 4 |
2651 | .IP "w\->set<function> (void *data = 0)" 4 |
2652 | .IX Item "w->set<function> (void *data = 0)" |
2652 | .IX Item "w->set<function> (void *data = 0)" |
2653 | Also sets a callback, but uses a static method or plain function as |
2653 | Also sets a callback, but uses a static method or plain function as |
2654 | callback. The optional \f(CW\*(C`data\*(C'\fR argument will be stored in the watcher's |
2654 | callback. The optional \f(CW\*(C`data\*(C'\fR argument will be stored in the watcher's |
… | |
… | |
2659 | See the method\-\f(CW\*(C`set\*(C'\fR above for more details. |
2659 | See the method\-\f(CW\*(C`set\*(C'\fR above for more details. |
2660 | .Sp |
2660 | .Sp |
2661 | Example: |
2661 | Example: |
2662 | .Sp |
2662 | .Sp |
2663 | .Vb 2 |
2663 | .Vb 2 |
2664 | \& static void io_cb (ev::io &w, int revents) { } |
2664 | \& static void io_cb (ev::io &w, int revents) { } |
2665 | \& iow.set <io_cb> (); |
2665 | \& iow.set <io_cb> (); |
2666 | .Ve |
2666 | .Ve |
2667 | .IP "w\->set (struct ev_loop *)" 4 |
2667 | .IP "w\->set (struct ev_loop *)" 4 |
2668 | .IX Item "w->set (struct ev_loop *)" |
2668 | .IX Item "w->set (struct ev_loop *)" |
2669 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
2669 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
2670 | do this when the watcher is inactive (and not pending either). |
2670 | do this when the watcher is inactive (and not pending either). |
2671 | .IP "w\->set ([args])" 4 |
2671 | .IP "w\->set ([arguments])" 4 |
2672 | .IX Item "w->set ([args])" |
2672 | .IX Item "w->set ([arguments])" |
2673 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
2673 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same arguments. Must be |
2674 | called at least once. Unlike the C counterpart, an active watcher gets |
2674 | called at least once. Unlike the C counterpart, an active watcher gets |
2675 | automatically stopped and restarted when reconfiguring it with this |
2675 | automatically stopped and restarted when reconfiguring it with this |
2676 | method. |
2676 | method. |
2677 | .IP "w\->start ()" 4 |
2677 | .IP "w\->start ()" 4 |
2678 | .IX Item "w->start ()" |
2678 | .IX Item "w->start ()" |
… | |
… | |
2700 | .PP |
2700 | .PP |
2701 | Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in |
2701 | Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in |
2702 | the constructor. |
2702 | the constructor. |
2703 | .PP |
2703 | .PP |
2704 | .Vb 4 |
2704 | .Vb 4 |
2705 | \& class myclass |
2705 | \& class myclass |
2706 | \& { |
2706 | \& { |
2707 | \& ev::io io; void io_cb (ev::io &w, int revents); |
2707 | \& ev::io io; void io_cb (ev::io &w, int revents); |
2708 | \& ev:idle idle void idle_cb (ev::idle &w, int revents); |
2708 | \& ev:idle idle void idle_cb (ev::idle &w, int revents); |
2709 | \& |
2709 | \& |
2710 | \& myclass (int fd) |
2710 | \& myclass (int fd) |
2711 | \& { |
2711 | \& { |
2712 | \& io .set <myclass, &myclass::io_cb > (this); |
2712 | \& io .set <myclass, &myclass::io_cb > (this); |
2713 | \& idle.set <myclass, &myclass::idle_cb> (this); |
2713 | \& idle.set <myclass, &myclass::idle_cb> (this); |
2714 | \& |
2714 | \& |
2715 | \& io.start (fd, ev::READ); |
2715 | \& io.start (fd, ev::READ); |
2716 | \& } |
2716 | \& } |
2717 | \& }; |
2717 | \& }; |
2718 | .Ve |
2718 | .Ve |
2719 | .SH "OTHER LANGUAGE BINDINGS" |
2719 | .SH "OTHER LANGUAGE BINDINGS" |
2720 | .IX Header "OTHER LANGUAGE BINDINGS" |
2720 | .IX Header "OTHER LANGUAGE BINDINGS" |
2721 | Libev does not offer other language bindings itself, but bindings for a |
2721 | Libev does not offer other language bindings itself, but bindings for a |
2722 | numbe rof languages exist in the form of third-party packages. If you know |
2722 | number of languages exist in the form of third-party packages. If you know |
2723 | any interesting language binding in addition to the ones listed here, drop |
2723 | any interesting language binding in addition to the ones listed here, drop |
2724 | me a note. |
2724 | me a note. |
2725 | .IP "Perl" 4 |
2725 | .IP "Perl" 4 |
2726 | .IX Item "Perl" |
2726 | .IX Item "Perl" |
2727 | The \s-1EV\s0 module implements the full libev \s-1API\s0 and is actually used to test |
2727 | The \s-1EV\s0 module implements the full libev \s-1API\s0 and is actually used to test |
2728 | libev. \s-1EV\s0 is developed together with libev. Apart from the \s-1EV\s0 core module, |
2728 | libev. \s-1EV\s0 is developed together with libev. Apart from the \s-1EV\s0 core module, |
2729 | there are additional modules that implement libev-compatible interfaces |
2729 | there are additional modules that implement libev-compatible interfaces |
2730 | to \f(CW\*(C`libadns\*(C'\fR (\f(CW\*(C`EV::ADNS\*(C'\fR), \f(CW\*(C`Net::SNMP\*(C'\fR (\f(CW\*(C`Net::SNMP::EV\*(C'\fR) and the |
2730 | to \f(CW\*(C`libadns\*(C'\fR (\f(CW\*(C`EV::ADNS\*(C'\fR), \f(CW\*(C`Net::SNMP\*(C'\fR (\f(CW\*(C`Net::SNMP::EV\*(C'\fR) and the |
2731 | \&\f(CW\*(C`libglib\*(C'\fR event core (\f(CW\*(C`Glib::EV\*(C'\fR and \f(CW\*(C`EV::Glib\*(C'\fR). |
2731 | \&\f(CW\*(C`libglib\*(C'\fR event core (\f(CW\*(C`Glib::EV\*(C'\fR and \f(CW\*(C`EV::Glib\*(C'\fR). |
2732 | .Sp |
2732 | .Sp |
2733 | It can be found and installed via \s-1CPAN\s0, its homepage is found at |
2733 | It can be found and installed via \s-1CPAN\s0, its homepage is at |
2734 | <http://software.schmorp.de/pkg/EV>. |
2734 | <http://software.schmorp.de/pkg/EV>. |
|
|
2735 | .IP "Python" 4 |
|
|
2736 | .IX Item "Python" |
|
|
2737 | Python bindings can be found at <http://code.google.com/p/pyev/>. It |
|
|
2738 | seems to be quite complete and well-documented. Note, however, that the |
|
|
2739 | patch they require for libev is outright dangerous as it breaks the \s-1ABI\s0 |
|
|
2740 | for everybody else, and therefore, should never be applied in an installed |
|
|
2741 | libev (if python requires an incompatible \s-1ABI\s0 then it needs to embed |
|
|
2742 | libev). |
2735 | .IP "Ruby" 4 |
2743 | .IP "Ruby" 4 |
2736 | .IX Item "Ruby" |
2744 | .IX Item "Ruby" |
2737 | Tony Arcieri has written a ruby extension that offers access to a subset |
2745 | Tony Arcieri has written a ruby extension that offers access to a subset |
2738 | of the libev \s-1API\s0 and adds filehandle abstractions, asynchronous \s-1DNS\s0 and |
2746 | of the libev \s-1API\s0 and adds file handle abstractions, asynchronous \s-1DNS\s0 and |
2739 | more on top of it. It can be found via gem servers. Its homepage is at |
2747 | more on top of it. It can be found via gem servers. Its homepage is at |
2740 | <http://rev.rubyforge.org/>. |
2748 | <http://rev.rubyforge.org/>. |
2741 | .IP "D" 4 |
2749 | .IP "D" 4 |
2742 | .IX Item "D" |
2750 | .IX Item "D" |
2743 | Leandro Lucarella has written a D language binding (\fIev.d\fR) for libev, to |
2751 | Leandro Lucarella has written a D language binding (\fIev.d\fR) for libev, to |
2744 | be found at <http://git.llucax.com.ar/?p=software/ev.d.git;a=summary>. |
2752 | be found at <http://git.llucax.com.ar/?p=software/ev.d.git;a=summary>. |
2745 | .SH "MACRO MAGIC" |
2753 | .SH "MACRO MAGIC" |
2746 | .IX Header "MACRO MAGIC" |
2754 | .IX Header "MACRO MAGIC" |
2747 | Libev can be compiled with a variety of options, the most fundamantal |
2755 | Libev can be compiled with a variety of options, the most fundamental |
2748 | of which is \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) |
2756 | of which is \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) |
2749 | functions and callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
2757 | functions and callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
2750 | .PP |
2758 | .PP |
2751 | To make it easier to write programs that cope with either variant, the |
2759 | To make it easier to write programs that cope with either variant, the |
2752 | following macros are defined: |
2760 | following macros are defined: |
… | |
… | |
2756 | This provides the loop \fIargument\fR for functions, if one is required (\*(L"ev |
2764 | This provides the loop \fIargument\fR for functions, if one is required (\*(L"ev |
2757 | loop argument\*(R"). The \f(CW\*(C`EV_A\*(C'\fR form is used when this is the sole argument, |
2765 | loop argument\*(R"). The \f(CW\*(C`EV_A\*(C'\fR form is used when this is the sole argument, |
2758 | \&\f(CW\*(C`EV_A_\*(C'\fR is used when other arguments are following. Example: |
2766 | \&\f(CW\*(C`EV_A_\*(C'\fR is used when other arguments are following. Example: |
2759 | .Sp |
2767 | .Sp |
2760 | .Vb 3 |
2768 | .Vb 3 |
2761 | \& ev_unref (EV_A); |
2769 | \& ev_unref (EV_A); |
2762 | \& ev_timer_add (EV_A_ watcher); |
2770 | \& ev_timer_add (EV_A_ watcher); |
2763 | \& ev_loop (EV_A_ 0); |
2771 | \& ev_loop (EV_A_ 0); |
2764 | .Ve |
2772 | .Ve |
2765 | .Sp |
2773 | .Sp |
2766 | It assumes the variable \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR is in scope, |
2774 | It assumes the variable \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR is in scope, |
2767 | which is often provided by the following macro. |
2775 | which is often provided by the following macro. |
2768 | .ie n .IP """EV_P""\fR, \f(CW""EV_P_""" 4 |
2776 | .ie n .IP """EV_P""\fR, \f(CW""EV_P_""" 4 |
… | |
… | |
2771 | This provides the loop \fIparameter\fR for functions, if one is required (\*(L"ev |
2779 | This provides the loop \fIparameter\fR for functions, if one is required (\*(L"ev |
2772 | loop parameter\*(R"). The \f(CW\*(C`EV_P\*(C'\fR form is used when this is the sole parameter, |
2780 | loop parameter\*(R"). The \f(CW\*(C`EV_P\*(C'\fR form is used when this is the sole parameter, |
2773 | \&\f(CW\*(C`EV_P_\*(C'\fR is used when other parameters are following. Example: |
2781 | \&\f(CW\*(C`EV_P_\*(C'\fR is used when other parameters are following. Example: |
2774 | .Sp |
2782 | .Sp |
2775 | .Vb 2 |
2783 | .Vb 2 |
2776 | \& // this is how ev_unref is being declared |
2784 | \& // this is how ev_unref is being declared |
2777 | \& static void ev_unref (EV_P); |
2785 | \& static void ev_unref (EV_P); |
2778 | \& |
2786 | \& |
2779 | \& // this is how you can declare your typical callback |
2787 | \& // this is how you can declare your typical callback |
2780 | \& static void cb (EV_P_ ev_timer *w, int revents) |
2788 | \& static void cb (EV_P_ ev_timer *w, int revents) |
2781 | .Ve |
2789 | .Ve |
2782 | .Sp |
2790 | .Sp |
2783 | It declares a parameter \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR, quite |
2791 | It declares a parameter \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR, quite |
2784 | suitable for use with \f(CW\*(C`EV_A\*(C'\fR. |
2792 | suitable for use with \f(CW\*(C`EV_A\*(C'\fR. |
2785 | .ie n .IP """EV_DEFAULT""\fR, \f(CW""EV_DEFAULT_""" 4 |
2793 | .ie n .IP """EV_DEFAULT""\fR, \f(CW""EV_DEFAULT_""" 4 |
… | |
… | |
2801 | Example: Declare and initialise a check watcher, utilising the above |
2809 | Example: Declare and initialise a check watcher, utilising the above |
2802 | macros so it will work regardless of whether multiple loops are supported |
2810 | macros so it will work regardless of whether multiple loops are supported |
2803 | or not. |
2811 | or not. |
2804 | .PP |
2812 | .PP |
2805 | .Vb 5 |
2813 | .Vb 5 |
2806 | \& static void |
2814 | \& static void |
2807 | \& check_cb (EV_P_ ev_timer *w, int revents) |
2815 | \& check_cb (EV_P_ ev_timer *w, int revents) |
2808 | \& { |
2816 | \& { |
2809 | \& ev_check_stop (EV_A_ w); |
2817 | \& ev_check_stop (EV_A_ w); |
2810 | \& } |
2818 | \& } |
2811 | \& |
2819 | \& |
2812 | \& ev_check check; |
2820 | \& ev_check check; |
2813 | \& ev_check_init (&check, check_cb); |
2821 | \& ev_check_init (&check, check_cb); |
2814 | \& ev_check_start (EV_DEFAULT_ &check); |
2822 | \& ev_check_start (EV_DEFAULT_ &check); |
2815 | \& ev_loop (EV_DEFAULT_ 0); |
2823 | \& ev_loop (EV_DEFAULT_ 0); |
2816 | .Ve |
2824 | .Ve |
2817 | .SH "EMBEDDING" |
2825 | .SH "EMBEDDING" |
2818 | .IX Header "EMBEDDING" |
2826 | .IX Header "EMBEDDING" |
2819 | Libev can (and often is) directly embedded into host |
2827 | Libev can (and often is) directly embedded into host |
2820 | applications. Examples of applications that embed it include the Deliantra |
2828 | applications. Examples of applications that embed it include the Deliantra |
… | |
… | |
2826 | you can easily upgrade by simply copying (or having a checked-out copy of |
2834 | you can easily upgrade by simply copying (or having a checked-out copy of |
2827 | libev somewhere in your source tree). |
2835 | libev somewhere in your source tree). |
2828 | .Sh "\s-1FILESETS\s0" |
2836 | .Sh "\s-1FILESETS\s0" |
2829 | .IX Subsection "FILESETS" |
2837 | .IX Subsection "FILESETS" |
2830 | Depending on what features you need you need to include one or more sets of files |
2838 | Depending on what features you need you need to include one or more sets of files |
2831 | in your app. |
2839 | in your application. |
2832 | .PP |
2840 | .PP |
2833 | \fI\s-1CORE\s0 \s-1EVENT\s0 \s-1LOOP\s0\fR |
2841 | \fI\s-1CORE\s0 \s-1EVENT\s0 \s-1LOOP\s0\fR |
2834 | .IX Subsection "CORE EVENT LOOP" |
2842 | .IX Subsection "CORE EVENT LOOP" |
2835 | .PP |
2843 | .PP |
2836 | To include only the libev core (all the \f(CW\*(C`ev_*\*(C'\fR functions), with manual |
2844 | To include only the libev core (all the \f(CW\*(C`ev_*\*(C'\fR functions), with manual |
2837 | configuration (no autoconf): |
2845 | configuration (no autoconf): |
2838 | .PP |
2846 | .PP |
2839 | .Vb 2 |
2847 | .Vb 2 |
2840 | \& #define EV_STANDALONE 1 |
2848 | \& #define EV_STANDALONE 1 |
2841 | \& #include "ev.c" |
2849 | \& #include "ev.c" |
2842 | .Ve |
2850 | .Ve |
2843 | .PP |
2851 | .PP |
2844 | This will automatically include \fIev.h\fR, too, and should be done in a |
2852 | This will automatically include \fIev.h\fR, too, and should be done in a |
2845 | single C source file only to provide the function implementations. To use |
2853 | single C source file only to provide the function implementations. To use |
2846 | it, do the same for \fIev.h\fR in all files wishing to use this \s-1API\s0 (best |
2854 | it, do the same for \fIev.h\fR in all files wishing to use this \s-1API\s0 (best |
2847 | done by writing a wrapper around \fIev.h\fR that you can include instead and |
2855 | done by writing a wrapper around \fIev.h\fR that you can include instead and |
2848 | where you can put other configuration options): |
2856 | where you can put other configuration options): |
2849 | .PP |
2857 | .PP |
2850 | .Vb 2 |
2858 | .Vb 2 |
2851 | \& #define EV_STANDALONE 1 |
2859 | \& #define EV_STANDALONE 1 |
2852 | \& #include "ev.h" |
2860 | \& #include "ev.h" |
2853 | .Ve |
2861 | .Ve |
2854 | .PP |
2862 | .PP |
2855 | Both header files and implementation files can be compiled with a \*(C+ |
2863 | Both header files and implementation files can be compiled with a \*(C+ |
2856 | compiler (at least, thats a stated goal, and breakage will be treated |
2864 | compiler (at least, thats a stated goal, and breakage will be treated |
2857 | as a bug). |
2865 | as a bug). |
2858 | .PP |
2866 | .PP |
2859 | You need the following files in your source tree, or in a directory |
2867 | You need the following files in your source tree, or in a directory |
2860 | in your include path (e.g. in libev/ when using \-Ilibev): |
2868 | in your include path (e.g. in libev/ when using \-Ilibev): |
2861 | .PP |
2869 | .PP |
2862 | .Vb 4 |
2870 | .Vb 4 |
2863 | \& ev.h |
2871 | \& ev.h |
2864 | \& ev.c |
2872 | \& ev.c |
2865 | \& ev_vars.h |
2873 | \& ev_vars.h |
2866 | \& ev_wrap.h |
2874 | \& ev_wrap.h |
2867 | \& |
2875 | \& |
2868 | \& ev_win32.c required on win32 platforms only |
2876 | \& ev_win32.c required on win32 platforms only |
2869 | \& |
2877 | \& |
2870 | \& ev_select.c only when select backend is enabled (which is enabled by default) |
2878 | \& ev_select.c only when select backend is enabled (which is enabled by default) |
2871 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
2879 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
2872 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
2880 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
2873 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
2881 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
2874 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
2882 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
2875 | .Ve |
2883 | .Ve |
2876 | .PP |
2884 | .PP |
2877 | \&\fIev.c\fR includes the backend files directly when enabled, so you only need |
2885 | \&\fIev.c\fR includes the backend files directly when enabled, so you only need |
2878 | to compile this single file. |
2886 | to compile this single file. |
2879 | .PP |
2887 | .PP |
… | |
… | |
2881 | .IX Subsection "LIBEVENT COMPATIBILITY API" |
2889 | .IX Subsection "LIBEVENT COMPATIBILITY API" |
2882 | .PP |
2890 | .PP |
2883 | To include the libevent compatibility \s-1API\s0, also include: |
2891 | To include the libevent compatibility \s-1API\s0, also include: |
2884 | .PP |
2892 | .PP |
2885 | .Vb 1 |
2893 | .Vb 1 |
2886 | \& #include "event.c" |
2894 | \& #include "event.c" |
2887 | .Ve |
2895 | .Ve |
2888 | .PP |
2896 | .PP |
2889 | in the file including \fIev.c\fR, and: |
2897 | in the file including \fIev.c\fR, and: |
2890 | .PP |
2898 | .PP |
2891 | .Vb 1 |
2899 | .Vb 1 |
2892 | \& #include "event.h" |
2900 | \& #include "event.h" |
2893 | .Ve |
2901 | .Ve |
2894 | .PP |
2902 | .PP |
2895 | in the files that want to use the libevent \s-1API\s0. This also includes \fIev.h\fR. |
2903 | in the files that want to use the libevent \s-1API\s0. This also includes \fIev.h\fR. |
2896 | .PP |
2904 | .PP |
2897 | You need the following additional files for this: |
2905 | You need the following additional files for this: |
2898 | .PP |
2906 | .PP |
2899 | .Vb 2 |
2907 | .Vb 2 |
2900 | \& event.h |
2908 | \& event.h |
2901 | \& event.c |
2909 | \& event.c |
2902 | .Ve |
2910 | .Ve |
2903 | .PP |
2911 | .PP |
2904 | \fI\s-1AUTOCONF\s0 \s-1SUPPORT\s0\fR |
2912 | \fI\s-1AUTOCONF\s0 \s-1SUPPORT\s0\fR |
2905 | .IX Subsection "AUTOCONF SUPPORT" |
2913 | .IX Subsection "AUTOCONF SUPPORT" |
2906 | .PP |
2914 | .PP |
2907 | Instead of using \f(CW\*(C`EV_STANDALONE=1\*(C'\fR and providing your config in |
2915 | Instead of using \f(CW\*(C`EV_STANDALONE=1\*(C'\fR and providing your configuration in |
2908 | whatever way you want, you can also \f(CW\*(C`m4_include([libev.m4])\*(C'\fR in your |
2916 | whatever way you want, you can also \f(CW\*(C`m4_include([libev.m4])\*(C'\fR in your |
2909 | \&\fIconfigure.ac\fR and leave \f(CW\*(C`EV_STANDALONE\*(C'\fR undefined. \fIev.c\fR will then |
2917 | \&\fIconfigure.ac\fR and leave \f(CW\*(C`EV_STANDALONE\*(C'\fR undefined. \fIev.c\fR will then |
2910 | include \fIconfig.h\fR and configure itself accordingly. |
2918 | include \fIconfig.h\fR and configure itself accordingly. |
2911 | .PP |
2919 | .PP |
2912 | For this of course you need the m4 file: |
2920 | For this of course you need the m4 file: |
2913 | .PP |
2921 | .PP |
2914 | .Vb 1 |
2922 | .Vb 1 |
2915 | \& libev.m4 |
2923 | \& libev.m4 |
2916 | .Ve |
2924 | .Ve |
2917 | .Sh "\s-1PREPROCESSOR\s0 \s-1SYMBOLS/MACROS\s0" |
2925 | .Sh "\s-1PREPROCESSOR\s0 \s-1SYMBOLS/MACROS\s0" |
2918 | .IX Subsection "PREPROCESSOR SYMBOLS/MACROS" |
2926 | .IX Subsection "PREPROCESSOR SYMBOLS/MACROS" |
2919 | Libev can be configured via a variety of preprocessor symbols you have to |
2927 | Libev can be configured via a variety of preprocessor symbols you have to |
2920 | define before including any of its files. The default in the absense of |
2928 | define before including any of its files. The default in the absence of |
2921 | autoconf is noted for every option. |
2929 | autoconf is noted for every option. |
2922 | .IP "\s-1EV_STANDALONE\s0" 4 |
2930 | .IP "\s-1EV_STANDALONE\s0" 4 |
2923 | .IX Item "EV_STANDALONE" |
2931 | .IX Item "EV_STANDALONE" |
2924 | Must always be \f(CW1\fR if you do not use autoconf configuration, which |
2932 | Must always be \f(CW1\fR if you do not use autoconf configuration, which |
2925 | keeps libev from including \fIconfig.h\fR, and it also defines dummy |
2933 | keeps libev from including \fIconfig.h\fR, and it also defines dummy |
… | |
… | |
2927 | supported). It will also not define any of the structs usually found in |
2935 | supported). It will also not define any of the structs usually found in |
2928 | \&\fIevent.h\fR that are not directly supported by the libev core alone. |
2936 | \&\fIevent.h\fR that are not directly supported by the libev core alone. |
2929 | .IP "\s-1EV_USE_MONOTONIC\s0" 4 |
2937 | .IP "\s-1EV_USE_MONOTONIC\s0" 4 |
2930 | .IX Item "EV_USE_MONOTONIC" |
2938 | .IX Item "EV_USE_MONOTONIC" |
2931 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
2939 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
2932 | monotonic clock option at both compiletime and runtime. Otherwise no use |
2940 | monotonic clock option at both compile time and runtime. Otherwise no use |
2933 | of the monotonic clock option will be attempted. If you enable this, you |
2941 | of the monotonic clock option will be attempted. If you enable this, you |
2934 | usually have to link against librt or something similar. Enabling it when |
2942 | usually have to link against librt or something similar. Enabling it when |
2935 | the functionality isn't available is safe, though, although you have |
2943 | the functionality isn't available is safe, though, although you have |
2936 | to make sure you link against any libraries where the \f(CW\*(C`clock_gettime\*(C'\fR |
2944 | to make sure you link against any libraries where the \f(CW\*(C`clock_gettime\*(C'\fR |
2937 | function is hiding in (often \fI\-lrt\fR). |
2945 | function is hiding in (often \fI\-lrt\fR). |
2938 | .IP "\s-1EV_USE_REALTIME\s0" 4 |
2946 | .IP "\s-1EV_USE_REALTIME\s0" 4 |
2939 | .IX Item "EV_USE_REALTIME" |
2947 | .IX Item "EV_USE_REALTIME" |
2940 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
2948 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
2941 | realtime clock option at compiletime (and assume its availability at |
2949 | real-time clock option at compile time (and assume its availability at |
2942 | runtime if successful). Otherwise no use of the realtime clock option will |
2950 | runtime if successful). Otherwise no use of the real-time clock option will |
2943 | be attempted. This effectively replaces \f(CW\*(C`gettimeofday\*(C'\fR by \f(CW\*(C`clock_get |
2951 | be attempted. This effectively replaces \f(CW\*(C`gettimeofday\*(C'\fR by \f(CW\*(C`clock_get |
2944 | (CLOCK_REALTIME, ...)\*(C'\fR and will not normally affect correctness. See the |
2952 | (CLOCK_REALTIME, ...)\*(C'\fR and will not normally affect correctness. See the |
2945 | note about libraries in the description of \f(CW\*(C`EV_USE_MONOTONIC\*(C'\fR, though. |
2953 | note about libraries in the description of \f(CW\*(C`EV_USE_MONOTONIC\*(C'\fR, though. |
2946 | .IP "\s-1EV_USE_NANOSLEEP\s0" 4 |
2954 | .IP "\s-1EV_USE_NANOSLEEP\s0" 4 |
2947 | .IX Item "EV_USE_NANOSLEEP" |
2955 | .IX Item "EV_USE_NANOSLEEP" |
… | |
… | |
2955 | If undefined, it will be enabled if the headers indicate GNU/Linux + Glibc |
2963 | If undefined, it will be enabled if the headers indicate GNU/Linux + Glibc |
2956 | 2.7 or newer, otherwise disabled. |
2964 | 2.7 or newer, otherwise disabled. |
2957 | .IP "\s-1EV_USE_SELECT\s0" 4 |
2965 | .IP "\s-1EV_USE_SELECT\s0" 4 |
2958 | .IX Item "EV_USE_SELECT" |
2966 | .IX Item "EV_USE_SELECT" |
2959 | If undefined or defined to be \f(CW1\fR, libev will compile in support for the |
2967 | If undefined or defined to be \f(CW1\fR, libev will compile in support for the |
2960 | \&\f(CW\*(C`select\*(C'\fR(2) backend. No attempt at autodetection will be done: if no |
2968 | \&\f(CW\*(C`select\*(C'\fR(2) backend. No attempt at auto-detection will be done: if no |
2961 | other method takes over, select will be it. Otherwise the select backend |
2969 | other method takes over, select will be it. Otherwise the select backend |
2962 | will not be compiled in. |
2970 | will not be compiled in. |
2963 | .IP "\s-1EV_SELECT_USE_FD_SET\s0" 4 |
2971 | .IP "\s-1EV_SELECT_USE_FD_SET\s0" 4 |
2964 | .IX Item "EV_SELECT_USE_FD_SET" |
2972 | .IX Item "EV_SELECT_USE_FD_SET" |
2965 | If defined to \f(CW1\fR, then the select backend will use the system \f(CW\*(C`fd_set\*(C'\fR |
2973 | If defined to \f(CW1\fR, then the select backend will use the system \f(CW\*(C`fd_set\*(C'\fR |
2966 | structure. This is useful if libev doesn't compile due to a missing |
2974 | structure. This is useful if libev doesn't compile due to a missing |
2967 | \&\f(CW\*(C`NFDBITS\*(C'\fR or \f(CW\*(C`fd_mask\*(C'\fR definition or it misguesses the bitset layout on |
2975 | \&\f(CW\*(C`NFDBITS\*(C'\fR or \f(CW\*(C`fd_mask\*(C'\fR definition or it mis-guesses the bitset layout on |
2968 | exotic systems. This usually limits the range of file descriptors to some |
2976 | exotic systems. This usually limits the range of file descriptors to some |
2969 | low limit such as 1024 or might have other limitations (winsocket only |
2977 | low limit such as 1024 or might have other limitations (winsocket only |
2970 | allows 64 sockets). The \f(CW\*(C`FD_SETSIZE\*(C'\fR macro, set before compilation, might |
2978 | allows 64 sockets). The \f(CW\*(C`FD_SETSIZE\*(C'\fR macro, set before compilation, might |
2971 | influence the size of the \f(CW\*(C`fd_set\*(C'\fR used. |
2979 | influence the size of the \f(CW\*(C`fd_set\*(C'\fR used. |
2972 | .IP "\s-1EV_SELECT_IS_WINSOCKET\s0" 4 |
2980 | .IP "\s-1EV_SELECT_IS_WINSOCKET\s0" 4 |
… | |
… | |
3014 | 10 port style backend. Its availability will be detected at runtime, |
3022 | 10 port style backend. Its availability will be detected at runtime, |
3015 | otherwise another method will be used as fallback. This is the preferred |
3023 | otherwise another method will be used as fallback. This is the preferred |
3016 | backend for Solaris 10 systems. |
3024 | backend for Solaris 10 systems. |
3017 | .IP "\s-1EV_USE_DEVPOLL\s0" 4 |
3025 | .IP "\s-1EV_USE_DEVPOLL\s0" 4 |
3018 | .IX Item "EV_USE_DEVPOLL" |
3026 | .IX Item "EV_USE_DEVPOLL" |
3019 | reserved for future expansion, works like the \s-1USE\s0 symbols above. |
3027 | Reserved for future expansion, works like the \s-1USE\s0 symbols above. |
3020 | .IP "\s-1EV_USE_INOTIFY\s0" 4 |
3028 | .IP "\s-1EV_USE_INOTIFY\s0" 4 |
3021 | .IX Item "EV_USE_INOTIFY" |
3029 | .IX Item "EV_USE_INOTIFY" |
3022 | If defined to be \f(CW1\fR, libev will compile in support for the Linux inotify |
3030 | If defined to be \f(CW1\fR, libev will compile in support for the Linux inotify |
3023 | interface to speed up \f(CW\*(C`ev_stat\*(C'\fR watchers. Its actual availability will |
3031 | interface to speed up \f(CW\*(C`ev_stat\*(C'\fR watchers. Its actual availability will |
3024 | be detected at runtime. If undefined, it will be enabled if the headers |
3032 | be detected at runtime. If undefined, it will be enabled if the headers |
… | |
… | |
3029 | access is atomic with respect to other threads or signal contexts. No such |
3037 | access is atomic with respect to other threads or signal contexts. No such |
3030 | type is easily found in the C language, so you can provide your own type |
3038 | type is easily found in the C language, so you can provide your own type |
3031 | that you know is safe for your purposes. It is used both for signal handler \*(L"locking\*(R" |
3039 | that you know is safe for your purposes. It is used both for signal handler \*(L"locking\*(R" |
3032 | as well as for signal and thread safety in \f(CW\*(C`ev_async\*(C'\fR watchers. |
3040 | as well as for signal and thread safety in \f(CW\*(C`ev_async\*(C'\fR watchers. |
3033 | .Sp |
3041 | .Sp |
3034 | In the absense of this define, libev will use \f(CW\*(C`sig_atomic_t volatile\*(C'\fR |
3042 | In the absence of this define, libev will use \f(CW\*(C`sig_atomic_t volatile\*(C'\fR |
3035 | (from \fIsignal.h\fR), which is usually good enough on most platforms. |
3043 | (from \fIsignal.h\fR), which is usually good enough on most platforms. |
3036 | .IP "\s-1EV_H\s0" 4 |
3044 | .IP "\s-1EV_H\s0" 4 |
3037 | .IX Item "EV_H" |
3045 | .IX Item "EV_H" |
3038 | The name of the \fIev.h\fR header file used to include it. The default if |
3046 | The name of the \fIev.h\fR header file used to include it. The default if |
3039 | undefined is \f(CW"ev.h"\fR in \fIevent.h\fR, \fIev.c\fR and \fIev++.h\fR. This can be |
3047 | undefined is \f(CW"ev.h"\fR in \fIevent.h\fR, \fIev.c\fR and \fIev++.h\fR. This can be |
… | |
… | |
3074 | When doing priority-based operations, libev usually has to linearly search |
3082 | When doing priority-based operations, libev usually has to linearly search |
3075 | all the priorities, so having many of them (hundreds) uses a lot of space |
3083 | all the priorities, so having many of them (hundreds) uses a lot of space |
3076 | and time, so using the defaults of five priorities (\-2 .. +2) is usually |
3084 | and time, so using the defaults of five priorities (\-2 .. +2) is usually |
3077 | fine. |
3085 | fine. |
3078 | .Sp |
3086 | .Sp |
3079 | If your embedding app does not need any priorities, defining these both to |
3087 | If your embedding application does not need any priorities, defining these both to |
3080 | \&\f(CW0\fR will save some memory and cpu. |
3088 | \&\f(CW0\fR will save some memory and \s-1CPU\s0. |
3081 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
3089 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
3082 | .IX Item "EV_PERIODIC_ENABLE" |
3090 | .IX Item "EV_PERIODIC_ENABLE" |
3083 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
3091 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
3084 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
3092 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
3085 | code. |
3093 | code. |
… | |
… | |
3106 | defined to be \f(CW0\fR, then they are not. |
3114 | defined to be \f(CW0\fR, then they are not. |
3107 | .IP "\s-1EV_MINIMAL\s0" 4 |
3115 | .IP "\s-1EV_MINIMAL\s0" 4 |
3108 | .IX Item "EV_MINIMAL" |
3116 | .IX Item "EV_MINIMAL" |
3109 | If you need to shave off some kilobytes of code at the expense of some |
3117 | If you need to shave off some kilobytes of code at the expense of some |
3110 | speed, define this symbol to \f(CW1\fR. Currently this is used to override some |
3118 | speed, define this symbol to \f(CW1\fR. Currently this is used to override some |
3111 | inlining decisions, saves roughly 30% codesize of amd64. It also selects a |
3119 | inlining decisions, saves roughly 30% code size on amd64. It also selects a |
3112 | much smaller 2\-heap for timer management over the default 4\-heap. |
3120 | much smaller 2\-heap for timer management over the default 4\-heap. |
3113 | .IP "\s-1EV_PID_HASHSIZE\s0" 4 |
3121 | .IP "\s-1EV_PID_HASHSIZE\s0" 4 |
3114 | .IX Item "EV_PID_HASHSIZE" |
3122 | .IX Item "EV_PID_HASHSIZE" |
3115 | \&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by |
3123 | \&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by |
3116 | pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more |
3124 | pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more |
… | |
… | |
3126 | .IP "\s-1EV_USE_4HEAP\s0" 4 |
3134 | .IP "\s-1EV_USE_4HEAP\s0" 4 |
3127 | .IX Item "EV_USE_4HEAP" |
3135 | .IX Item "EV_USE_4HEAP" |
3128 | Heaps are not very cache-efficient. To improve the cache-efficiency of the |
3136 | Heaps are not very cache-efficient. To improve the cache-efficiency of the |
3129 | timer and periodics heap, libev uses a 4\-heap when this symbol is defined |
3137 | timer and periodics heap, libev uses a 4\-heap when this symbol is defined |
3130 | to \f(CW1\fR. The 4\-heap uses more complicated (longer) code but has |
3138 | to \f(CW1\fR. The 4\-heap uses more complicated (longer) code but has |
3131 | noticably faster performance with many (thousands) of watchers. |
3139 | noticeably faster performance with many (thousands) of watchers. |
3132 | .Sp |
3140 | .Sp |
3133 | The default is \f(CW1\fR unless \f(CW\*(C`EV_MINIMAL\*(C'\fR is set in which case it is \f(CW0\fR |
3141 | The default is \f(CW1\fR unless \f(CW\*(C`EV_MINIMAL\*(C'\fR is set in which case it is \f(CW0\fR |
3134 | (disabled). |
3142 | (disabled). |
3135 | .IP "\s-1EV_HEAP_CACHE_AT\s0" 4 |
3143 | .IP "\s-1EV_HEAP_CACHE_AT\s0" 4 |
3136 | .IX Item "EV_HEAP_CACHE_AT" |
3144 | .IX Item "EV_HEAP_CACHE_AT" |
3137 | Heaps are not very cache-efficient. To improve the cache-efficiency of the |
3145 | Heaps are not very cache-efficient. To improve the cache-efficiency of the |
3138 | timer and periodics heap, libev can cache the timestamp (\fIat\fR) within |
3146 | timer and periodics heap, libev can cache the timestamp (\fIat\fR) within |
3139 | the heap structure (selected by defining \f(CW\*(C`EV_HEAP_CACHE_AT\*(C'\fR to \f(CW1\fR), |
3147 | the heap structure (selected by defining \f(CW\*(C`EV_HEAP_CACHE_AT\*(C'\fR to \f(CW1\fR), |
3140 | which uses 8\-12 bytes more per watcher and a few hundred bytes more code, |
3148 | which uses 8\-12 bytes more per watcher and a few hundred bytes more code, |
3141 | but avoids random read accesses on heap changes. This improves performance |
3149 | but avoids random read accesses on heap changes. This improves performance |
3142 | noticably with with many (hundreds) of watchers. |
3150 | noticeably with with many (hundreds) of watchers. |
3143 | .Sp |
3151 | .Sp |
3144 | The default is \f(CW1\fR unless \f(CW\*(C`EV_MINIMAL\*(C'\fR is set in which case it is \f(CW0\fR |
3152 | The default is \f(CW1\fR unless \f(CW\*(C`EV_MINIMAL\*(C'\fR is set in which case it is \f(CW0\fR |
3145 | (disabled). |
3153 | (disabled). |
3146 | .IP "\s-1EV_VERIFY\s0" 4 |
3154 | .IP "\s-1EV_VERIFY\s0" 4 |
3147 | .IX Item "EV_VERIFY" |
3155 | .IX Item "EV_VERIFY" |
… | |
… | |
3163 | though, and it must be identical each time. |
3171 | though, and it must be identical each time. |
3164 | .Sp |
3172 | .Sp |
3165 | For example, the perl \s-1EV\s0 module uses something like this: |
3173 | For example, the perl \s-1EV\s0 module uses something like this: |
3166 | .Sp |
3174 | .Sp |
3167 | .Vb 3 |
3175 | .Vb 3 |
3168 | \& #define EV_COMMON \e |
3176 | \& #define EV_COMMON \e |
3169 | \& SV *self; /* contains this struct */ \e |
3177 | \& SV *self; /* contains this struct */ \e |
3170 | \& SV *cb_sv, *fh /* note no trailing ";" */ |
3178 | \& SV *cb_sv, *fh /* note no trailing ";" */ |
3171 | .Ve |
3179 | .Ve |
3172 | .IP "\s-1EV_CB_DECLARE\s0 (type)" 4 |
3180 | .IP "\s-1EV_CB_DECLARE\s0 (type)" 4 |
3173 | .IX Item "EV_CB_DECLARE (type)" |
3181 | .IX Item "EV_CB_DECLARE (type)" |
3174 | .PD 0 |
3182 | .PD 0 |
3175 | .IP "\s-1EV_CB_INVOKE\s0 (watcher, revents)" 4 |
3183 | .IP "\s-1EV_CB_INVOKE\s0 (watcher, revents)" 4 |
… | |
… | |
3183 | their default definitions. One possible use for overriding these is to |
3191 | their default definitions. One possible use for overriding these is to |
3184 | avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use |
3192 | avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use |
3185 | method calls instead of plain function calls in \*(C+. |
3193 | method calls instead of plain function calls in \*(C+. |
3186 | .Sh "\s-1EXPORTED\s0 \s-1API\s0 \s-1SYMBOLS\s0" |
3194 | .Sh "\s-1EXPORTED\s0 \s-1API\s0 \s-1SYMBOLS\s0" |
3187 | .IX Subsection "EXPORTED API SYMBOLS" |
3195 | .IX Subsection "EXPORTED API SYMBOLS" |
3188 | If you need to re-export the \s-1API\s0 (e.g. via a dll) and you need a list of |
3196 | If you need to re-export the \s-1API\s0 (e.g. via a \s-1DLL\s0) and you need a list of |
3189 | exported symbols, you can use the provided \fISymbol.*\fR files which list |
3197 | exported symbols, you can use the provided \fISymbol.*\fR files which list |
3190 | all public symbols, one per line: |
3198 | all public symbols, one per line: |
3191 | .PP |
3199 | .PP |
3192 | .Vb 2 |
3200 | .Vb 2 |
3193 | \& Symbols.ev for libev proper |
3201 | \& Symbols.ev for libev proper |
3194 | \& Symbols.event for the libevent emulation |
3202 | \& Symbols.event for the libevent emulation |
3195 | .Ve |
3203 | .Ve |
3196 | .PP |
3204 | .PP |
3197 | This can also be used to rename all public symbols to avoid clashes with |
3205 | This can also be used to rename all public symbols to avoid clashes with |
3198 | multiple versions of libev linked together (which is obviously bad in |
3206 | multiple versions of libev linked together (which is obviously bad in |
3199 | itself, but sometimes it is inconvinient to avoid this). |
3207 | itself, but sometimes it is inconvenient to avoid this). |
3200 | .PP |
3208 | .PP |
3201 | A sed command like this will create wrapper \f(CW\*(C`#define\*(C'\fR's that you need to |
3209 | A sed command like this will create wrapper \f(CW\*(C`#define\*(C'\fR's that you need to |
3202 | include before including \fIev.h\fR: |
3210 | include before including \fIev.h\fR: |
3203 | .PP |
3211 | .PP |
3204 | .Vb 1 |
3212 | .Vb 1 |
… | |
… | |
3225 | .PP |
3233 | .PP |
3226 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
3234 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
3227 | that everybody includes and which overrides some configure choices: |
3235 | that everybody includes and which overrides some configure choices: |
3228 | .PP |
3236 | .PP |
3229 | .Vb 9 |
3237 | .Vb 9 |
3230 | \& #define EV_MINIMAL 1 |
3238 | \& #define EV_MINIMAL 1 |
3231 | \& #define EV_USE_POLL 0 |
3239 | \& #define EV_USE_POLL 0 |
3232 | \& #define EV_MULTIPLICITY 0 |
3240 | \& #define EV_MULTIPLICITY 0 |
3233 | \& #define EV_PERIODIC_ENABLE 0 |
3241 | \& #define EV_PERIODIC_ENABLE 0 |
3234 | \& #define EV_STAT_ENABLE 0 |
3242 | \& #define EV_STAT_ENABLE 0 |
3235 | \& #define EV_FORK_ENABLE 0 |
3243 | \& #define EV_FORK_ENABLE 0 |
3236 | \& #define EV_CONFIG_H <config.h> |
3244 | \& #define EV_CONFIG_H <config.h> |
3237 | \& #define EV_MINPRI 0 |
3245 | \& #define EV_MINPRI 0 |
3238 | \& #define EV_MAXPRI 0 |
3246 | \& #define EV_MAXPRI 0 |
3239 | \& |
3247 | \& |
3240 | \& #include "ev++.h" |
3248 | \& #include "ev++.h" |
3241 | .Ve |
3249 | .Ve |
3242 | .PP |
3250 | .PP |
3243 | And a \fIev_cpp.C\fR implementation file that contains libev proper and is compiled: |
3251 | And a \fIev_cpp.C\fR implementation file that contains libev proper and is compiled: |
3244 | .PP |
3252 | .PP |
3245 | .Vb 2 |
3253 | .Vb 2 |
3246 | \& #include "ev_cpp.h" |
3254 | \& #include "ev_cpp.h" |
3247 | \& #include "ev.c" |
3255 | \& #include "ev.c" |
3248 | .Ve |
3256 | .Ve |
3249 | .SH "THREADS AND COROUTINES" |
3257 | .SH "THREADS AND COROUTINES" |
3250 | .IX Header "THREADS AND COROUTINES" |
3258 | .IX Header "THREADS AND COROUTINES" |
3251 | .Sh "\s-1THREADS\s0" |
3259 | .Sh "\s-1THREADS\s0" |
3252 | .IX Subsection "THREADS" |
3260 | .IX Subsection "THREADS" |
3253 | Libev itself is completely threadsafe, but it uses no locking. This |
3261 | Libev itself is completely thread-safe, but it uses no locking. This |
3254 | means that you can use as many loops as you want in parallel, as long as |
3262 | means that you can use as many loops as you want in parallel, as long as |
3255 | only one thread ever calls into one libev function with the same loop |
3263 | only one thread ever calls into one libev function with the same loop |
3256 | parameter. |
3264 | parameter. |
3257 | .PP |
3265 | .PP |
3258 | Or put differently: calls with different loop parameters can be done in |
3266 | Or put differently: calls with different loop parameters can be done in |
… | |
… | |
3263 | .PP |
3271 | .PP |
3264 | If you want to know which design is best for your problem, then I cannot |
3272 | If you want to know which design is best for your problem, then I cannot |
3265 | help you but by giving some generic advice: |
3273 | help you but by giving some generic advice: |
3266 | .IP "\(bu" 4 |
3274 | .IP "\(bu" 4 |
3267 | most applications have a main thread: use the default libev loop |
3275 | most applications have a main thread: use the default libev loop |
3268 | in that thread, or create a seperate thread running only the default loop. |
3276 | in that thread, or create a separate thread running only the default loop. |
3269 | .Sp |
3277 | .Sp |
3270 | This helps integrating other libraries or software modules that use libev |
3278 | This helps integrating other libraries or software modules that use libev |
3271 | themselves and don't care/know about threading. |
3279 | themselves and don't care/know about threading. |
3272 | .IP "\(bu" 4 |
3280 | .IP "\(bu" 4 |
3273 | one loop per thread is usually a good model. |
3281 | one loop per thread is usually a good model. |
3274 | .Sp |
3282 | .Sp |
3275 | Doing this is almost never wrong, sometimes a better-performance model |
3283 | Doing this is almost never wrong, sometimes a better-performance model |
3276 | exists, but it is always a good start. |
3284 | exists, but it is always a good start. |
3277 | .IP "\(bu" 4 |
3285 | .IP "\(bu" 4 |
3278 | other models exist, such as the leader/follower pattern, where one |
3286 | other models exist, such as the leader/follower pattern, where one |
3279 | loop is handed through multiple threads in a kind of round-robbin fashion. |
3287 | loop is handed through multiple threads in a kind of round-robin fashion. |
3280 | .Sp |
3288 | .Sp |
3281 | Chosing a model is hard \- look around, learn, know that usually you cna do |
3289 | Choosing a model is hard \- look around, learn, know that usually you can do |
3282 | better than you currently do :\-) |
3290 | better than you currently do :\-) |
3283 | .IP "\(bu" 4 |
3291 | .IP "\(bu" 4 |
3284 | often you need to talk to some other thread which blocks in the |
3292 | often you need to talk to some other thread which blocks in the |
3285 | event loop \- \f(CW\*(C`ev_async\*(C'\fR watchers can be used to wake them up from other |
3293 | event loop \- \f(CW\*(C`ev_async\*(C'\fR watchers can be used to wake them up from other |
3286 | threads safely (or from signal contexts...). |
3294 | threads safely (or from signal contexts...). |
3287 | .Sh "\s-1COROUTINES\s0" |
3295 | .Sh "\s-1COROUTINES\s0" |
3288 | .IX Subsection "COROUTINES" |
3296 | .IX Subsection "COROUTINES" |
3289 | Libev is much more accomodating to coroutines (\*(L"cooperative threads\*(R"): |
3297 | Libev is much more accommodating to coroutines (\*(L"cooperative threads\*(R"): |
3290 | libev fully supports nesting calls to it's functions from different |
3298 | libev fully supports nesting calls to it's functions from different |
3291 | coroutines (e.g. you can call \f(CW\*(C`ev_loop\*(C'\fR on the same loop from two |
3299 | coroutines (e.g. you can call \f(CW\*(C`ev_loop\*(C'\fR on the same loop from two |
3292 | different coroutines and switch freely between both coroutines running the |
3300 | different coroutines and switch freely between both coroutines running the |
3293 | loop, as long as you don't confuse yourself). The only exception is that |
3301 | loop, as long as you don't confuse yourself). The only exception is that |
3294 | you must not do this from \f(CW\*(C`ev_periodic\*(C'\fR reschedule callbacks. |
3302 | you must not do this from \f(CW\*(C`ev_periodic\*(C'\fR reschedule callbacks. |
… | |
… | |
3334 | fixed position in the storage array. |
3342 | fixed position in the storage array. |
3335 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
3343 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
3336 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
3344 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
3337 | A change means an I/O watcher gets started or stopped, which requires |
3345 | A change means an I/O watcher gets started or stopped, which requires |
3338 | libev to recalculate its status (and possibly tell the kernel, depending |
3346 | libev to recalculate its status (and possibly tell the kernel, depending |
3339 | on backend and wether \f(CW\*(C`ev_io_set\*(C'\fR was used). |
3347 | on backend and whether \f(CW\*(C`ev_io_set\*(C'\fR was used). |
3340 | .IP "Activating one watcher (putting it into the pending state): O(1)" 4 |
3348 | .IP "Activating one watcher (putting it into the pending state): O(1)" 4 |
3341 | .IX Item "Activating one watcher (putting it into the pending state): O(1)" |
3349 | .IX Item "Activating one watcher (putting it into the pending state): O(1)" |
3342 | .PD 0 |
3350 | .PD 0 |
3343 | .IP "Priority handling: O(number_of_priorities)" 4 |
3351 | .IP "Priority handling: O(number_of_priorities)" 4 |
3344 | .IX Item "Priority handling: O(number_of_priorities)" |
3352 | .IX Item "Priority handling: O(number_of_priorities)" |
… | |
… | |
3353 | .IP "Processing ev_async_send: O(number_of_async_watchers)" 4 |
3361 | .IP "Processing ev_async_send: O(number_of_async_watchers)" 4 |
3354 | .IX Item "Processing ev_async_send: O(number_of_async_watchers)" |
3362 | .IX Item "Processing ev_async_send: O(number_of_async_watchers)" |
3355 | .IP "Processing signals: O(max_signal_number)" 4 |
3363 | .IP "Processing signals: O(max_signal_number)" 4 |
3356 | .IX Item "Processing signals: O(max_signal_number)" |
3364 | .IX Item "Processing signals: O(max_signal_number)" |
3357 | .PD |
3365 | .PD |
3358 | Sending involves a syscall \fIiff\fR there were no other \f(CW\*(C`ev_async_send\*(C'\fR |
3366 | Sending involves a system call \fIiff\fR there were no other \f(CW\*(C`ev_async_send\*(C'\fR |
3359 | calls in the current loop iteration. Checking for async and signal events |
3367 | calls in the current loop iteration. Checking for async and signal events |
3360 | involves iterating over all running async watchers or all signal numbers. |
3368 | involves iterating over all running async watchers or all signal numbers. |
3361 | .SH "Win32 platform limitations and workarounds" |
3369 | .SH "WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS" |
3362 | .IX Header "Win32 platform limitations and workarounds" |
3370 | .IX Header "WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS" |
3363 | Win32 doesn't support any of the standards (e.g. \s-1POSIX\s0) that libev |
3371 | Win32 doesn't support any of the standards (e.g. \s-1POSIX\s0) that libev |
3364 | requires, and its I/O model is fundamentally incompatible with the \s-1POSIX\s0 |
3372 | requires, and its I/O model is fundamentally incompatible with the \s-1POSIX\s0 |
3365 | model. Libev still offers limited functionality on this platform in |
3373 | model. Libev still offers limited functionality on this platform in |
3366 | the form of the \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR backend, and only supports socket |
3374 | the form of the \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR backend, and only supports socket |
3367 | descriptors. This only applies when using Win32 natively, not when using |
3375 | descriptors. This only applies when using Win32 natively, not when using |
… | |
… | |
3373 | way (note also that glib is the slowest event library known to man). |
3381 | way (note also that glib is the slowest event library known to man). |
3374 | .PP |
3382 | .PP |
3375 | There is no supported compilation method available on windows except |
3383 | There is no supported compilation method available on windows except |
3376 | embedding it into other applications. |
3384 | embedding it into other applications. |
3377 | .PP |
3385 | .PP |
|
|
3386 | Not a libev limitation but worth mentioning: windows apparently doesn't |
|
|
3387 | accept large writes: instead of resulting in a partial write, windows will |
|
|
3388 | either accept everything or return \f(CW\*(C`ENOBUFS\*(C'\fR if the buffer is too large, |
|
|
3389 | so make sure you only write small amounts into your sockets (less than a |
|
|
3390 | megabyte seems safe, but thsi apparently depends on the amount of memory |
|
|
3391 | available). |
|
|
3392 | .PP |
3378 | Due to the many, low, and arbitrary limits on the win32 platform and |
3393 | Due to the many, low, and arbitrary limits on the win32 platform and |
3379 | the abysmal performance of winsockets, using a large number of sockets |
3394 | the abysmal performance of winsockets, using a large number of sockets |
3380 | is not recommended (and not reasonable). If your program needs to use |
3395 | is not recommended (and not reasonable). If your program needs to use |
3381 | more than a hundred or so sockets, then likely it needs to use a totally |
3396 | more than a hundred or so sockets, then likely it needs to use a totally |
3382 | different implementation for windows, as libev offers the \s-1POSIX\s0 readiness |
3397 | different implementation for windows, as libev offers the \s-1POSIX\s0 readiness |
3383 | notification model, which cannot be implemented efficiently on windows |
3398 | notification model, which cannot be implemented efficiently on windows |
3384 | (microsoft monopoly games). |
3399 | (Microsoft monopoly games). |
|
|
3400 | .PP |
|
|
3401 | A typical way to use libev under windows is to embed it (see the embedding |
|
|
3402 | section for details) and use the following \fIevwrap.h\fR header file instead |
|
|
3403 | of \fIev.h\fR: |
|
|
3404 | .PP |
|
|
3405 | .Vb 2 |
|
|
3406 | \& #define EV_STANDALONE /* keeps ev from requiring config.h */ |
|
|
3407 | \& #define EV_SELECT_IS_WINSOCKET 1 /* configure libev for windows select */ |
|
|
3408 | \& |
|
|
3409 | \& #include "ev.h" |
|
|
3410 | .Ve |
|
|
3411 | .PP |
|
|
3412 | And compile the following \fIevwrap.c\fR file into your project (make sure |
|
|
3413 | you do \fInot\fR compile the \fIev.c\fR or any other embedded soruce files!): |
|
|
3414 | .PP |
|
|
3415 | .Vb 2 |
|
|
3416 | \& #include "evwrap.h" |
|
|
3417 | \& #include "ev.c" |
|
|
3418 | .Ve |
3385 | .IP "The winsocket select function" 4 |
3419 | .IP "The winsocket select function" 4 |
3386 | .IX Item "The winsocket select function" |
3420 | .IX Item "The winsocket select function" |
3387 | The winsocket \f(CW\*(C`select\*(C'\fR function doesn't follow \s-1POSIX\s0 in that it |
3421 | The winsocket \f(CW\*(C`select\*(C'\fR function doesn't follow \s-1POSIX\s0 in that it |
3388 | requires socket \fIhandles\fR and not socket \fIfile descriptors\fR (it is |
3422 | requires socket \fIhandles\fR and not socket \fIfile descriptors\fR (it is |
3389 | also extremely buggy). This makes select very inefficient, and also |
3423 | also extremely buggy). This makes select very inefficient, and also |
3390 | requires a mapping from file descriptors to socket handles. See the |
3424 | requires a mapping from file descriptors to socket handles (the Microsoft |
|
|
3425 | C runtime provides the function \f(CW\*(C`_open_osfhandle\*(C'\fR for this). See the |
3391 | discussion of the \f(CW\*(C`EV_SELECT_USE_FD_SET\*(C'\fR, \f(CW\*(C`EV_SELECT_IS_WINSOCKET\*(C'\fR and |
3426 | discussion of the \f(CW\*(C`EV_SELECT_USE_FD_SET\*(C'\fR, \f(CW\*(C`EV_SELECT_IS_WINSOCKET\*(C'\fR and |
3392 | \&\f(CW\*(C`EV_FD_TO_WIN32_HANDLE\*(C'\fR preprocessor symbols for more info. |
3427 | \&\f(CW\*(C`EV_FD_TO_WIN32_HANDLE\*(C'\fR preprocessor symbols for more info. |
3393 | .Sp |
3428 | .Sp |
3394 | The configuration for a \*(L"naked\*(R" win32 using the microsoft runtime |
3429 | The configuration for a \*(L"naked\*(R" win32 using the Microsoft runtime |
3395 | libraries and raw winsocket select is: |
3430 | libraries and raw winsocket select is: |
3396 | .Sp |
3431 | .Sp |
3397 | .Vb 2 |
3432 | .Vb 2 |
3398 | \& #define EV_USE_SELECT 1 |
3433 | \& #define EV_USE_SELECT 1 |
3399 | \& #define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */ |
3434 | \& #define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */ |
3400 | .Ve |
3435 | .Ve |
3401 | .Sp |
3436 | .Sp |
3402 | Note that winsockets handling of fd sets is O(n), so you can easily get a |
3437 | Note that winsockets handling of fd sets is O(n), so you can easily get a |
3403 | complexity in the O(nA\*^X) range when using win32. |
3438 | complexity in the O(nA\*^X) range when using win32. |
3404 | .IP "Limited number of file descriptors" 4 |
3439 | .IP "Limited number of file descriptors" 4 |
3405 | .IX Item "Limited number of file descriptors" |
3440 | .IX Item "Limited number of file descriptors" |
3406 | Windows has numerous arbitrary (and low) limits on things. |
3441 | Windows has numerous arbitrary (and low) limits on things. |
3407 | .Sp |
3442 | .Sp |
3408 | Early versions of winsocket's select only supported waiting for a maximum |
3443 | Early versions of winsocket's select only supported waiting for a maximum |
3409 | of \f(CW64\fR handles (probably owning to the fact that all windows kernels |
3444 | of \f(CW64\fR handles (probably owning to the fact that all windows kernels |
3410 | can only wait for \f(CW64\fR things at the same time internally; microsoft |
3445 | can only wait for \f(CW64\fR things at the same time internally; Microsoft |
3411 | recommends spawning a chain of threads and wait for 63 handles and the |
3446 | recommends spawning a chain of threads and wait for 63 handles and the |
3412 | previous thread in each. Great). |
3447 | previous thread in each. Great). |
3413 | .Sp |
3448 | .Sp |
3414 | Newer versions support more handles, but you need to define \f(CW\*(C`FD_SETSIZE\*(C'\fR |
3449 | Newer versions support more handles, but you need to define \f(CW\*(C`FD_SETSIZE\*(C'\fR |
3415 | to some high number (e.g. \f(CW2048\fR) before compiling the winsocket select |
3450 | to some high number (e.g. \f(CW2048\fR) before compiling the winsocket select |
3416 | call (which might be in libev or elsewhere, for example, perl does its own |
3451 | call (which might be in libev or elsewhere, for example, perl does its own |
3417 | select emulation on windows). |
3452 | select emulation on windows). |
3418 | .Sp |
3453 | .Sp |
3419 | Another limit is the number of file descriptors in the microsoft runtime |
3454 | Another limit is the number of file descriptors in the Microsoft runtime |
3420 | libraries, which by default is \f(CW64\fR (there must be a hidden \fI64\fR fetish |
3455 | libraries, which by default is \f(CW64\fR (there must be a hidden \fI64\fR fetish |
3421 | or something like this inside microsoft). You can increase this by calling |
3456 | or something like this inside Microsoft). You can increase this by calling |
3422 | \&\f(CW\*(C`_setmaxstdio\*(C'\fR, which can increase this limit to \f(CW2048\fR (another |
3457 | \&\f(CW\*(C`_setmaxstdio\*(C'\fR, which can increase this limit to \f(CW2048\fR (another |
3423 | arbitrary limit), but is broken in many versions of the microsoft runtime |
3458 | arbitrary limit), but is broken in many versions of the Microsoft runtime |
3424 | libraries. |
3459 | libraries. |
3425 | .Sp |
3460 | .Sp |
3426 | This might get you to about \f(CW512\fR or \f(CW2048\fR sockets (depending on |
3461 | This might get you to about \f(CW512\fR or \f(CW2048\fR sockets (depending on |
3427 | windows version and/or the phase of the moon). To get more, you need to |
3462 | windows version and/or the phase of the moon). To get more, you need to |
3428 | wrap all I/O functions and provide your own fd management, but the cost of |
3463 | wrap all I/O functions and provide your own fd management, but the cost of |
3429 | calling select (O(nA\*^X)) will likely make this unworkable. |
3464 | calling select (O(nA\*^X)) will likely make this unworkable. |
3430 | .SH "PORTABILITY REQUIREMENTS" |
3465 | .SH "PORTABILITY REQUIREMENTS" |
3431 | .IX Header "PORTABILITY REQUIREMENTS" |
3466 | .IX Header "PORTABILITY REQUIREMENTS" |
3432 | In addition to a working ISO-C implementation, libev relies on a few |
3467 | In addition to a working ISO-C implementation, libev relies on a few |
3433 | additional extensions: |
3468 | additional extensions: |
|
|
3469 | .ie n .IP """void (*)(ev_watcher_type *, int revents)""\fR must have compatible calling conventions regardless of \f(CW""ev_watcher_type *""." 4 |
|
|
3470 | .el .IP "\f(CWvoid (*)(ev_watcher_type *, int revents)\fR must have compatible calling conventions regardless of \f(CWev_watcher_type *\fR." 4 |
|
|
3471 | .IX Item "void (*)(ev_watcher_type *, int revents) must have compatible calling conventions regardless of ev_watcher_type *." |
|
|
3472 | Libev assumes not only that all watcher pointers have the same internal |
|
|
3473 | structure (guaranteed by \s-1POSIX\s0 but not by \s-1ISO\s0 C for example), but it also |
|
|
3474 | assumes that the same (machine) code can be used to call any watcher |
|
|
3475 | callback: The watcher callbacks have different type signatures, but libev |
|
|
3476 | calls them using an \f(CW\*(C`ev_watcher *\*(C'\fR internally. |
3434 | .ie n .IP """sig_atomic_t volatile"" must be thread-atomic as well" 4 |
3477 | .ie n .IP """sig_atomic_t volatile"" must be thread-atomic as well" 4 |
3435 | .el .IP "\f(CWsig_atomic_t volatile\fR must be thread-atomic as well" 4 |
3478 | .el .IP "\f(CWsig_atomic_t volatile\fR must be thread-atomic as well" 4 |
3436 | .IX Item "sig_atomic_t volatile must be thread-atomic as well" |
3479 | .IX Item "sig_atomic_t volatile must be thread-atomic as well" |
3437 | The type \f(CW\*(C`sig_atomic_t volatile\*(C'\fR (or whatever is defined as |
3480 | The type \f(CW\*(C`sig_atomic_t volatile\*(C'\fR (or whatever is defined as |
3438 | \&\f(CW\*(C`EV_ATOMIC_T\*(C'\fR) must be atomic w.r.t. accesses from different |
3481 | \&\f(CW\*(C`EV_ATOMIC_T\*(C'\fR) must be atomic w.r.t. accesses from different |
… | |
… | |
3475 | scared by this. |
3518 | scared by this. |
3476 | .PP |
3519 | .PP |
3477 | However, these are unavoidable for many reasons. For one, each compiler |
3520 | However, these are unavoidable for many reasons. For one, each compiler |
3478 | has different warnings, and each user has different tastes regarding |
3521 | has different warnings, and each user has different tastes regarding |
3479 | warning options. \*(L"Warn-free\*(R" code therefore cannot be a goal except when |
3522 | warning options. \*(L"Warn-free\*(R" code therefore cannot be a goal except when |
3480 | targetting a specific compiler and compiler-version. |
3523 | targeting a specific compiler and compiler-version. |
3481 | .PP |
3524 | .PP |
3482 | Another reason is that some compiler warnings require elaborate |
3525 | Another reason is that some compiler warnings require elaborate |
3483 | workarounds, or other changes to the code that make it less clear and less |
3526 | workarounds, or other changes to the code that make it less clear and less |
3484 | maintainable. |
3527 | maintainable. |
3485 | .PP |
3528 | .PP |
3486 | And of course, some compiler warnings are just plain stupid, or simply |
3529 | And of course, some compiler warnings are just plain stupid, or simply |
3487 | wrong (because they don't actually warn about the cindition their message |
3530 | wrong (because they don't actually warn about the condition their message |
3488 | seems to warn about). |
3531 | seems to warn about). |
3489 | .PP |
3532 | .PP |
3490 | While libev is written to generate as few warnings as possible, |
3533 | While libev is written to generate as few warnings as possible, |
3491 | \&\*(L"warn-free\*(R" code is not a goal, and it is recommended not to build libev |
3534 | \&\*(L"warn-free\*(R" code is not a goal, and it is recommended not to build libev |
3492 | with any compiler warnings enabled unless you are prepared to cope with |
3535 | with any compiler warnings enabled unless you are prepared to cope with |
… | |
… | |
3504 | \& ==2274== definitely lost: 0 bytes in 0 blocks. |
3547 | \& ==2274== definitely lost: 0 bytes in 0 blocks. |
3505 | \& ==2274== possibly lost: 0 bytes in 0 blocks. |
3548 | \& ==2274== possibly lost: 0 bytes in 0 blocks. |
3506 | \& ==2274== still reachable: 256 bytes in 1 blocks. |
3549 | \& ==2274== still reachable: 256 bytes in 1 blocks. |
3507 | .Ve |
3550 | .Ve |
3508 | .PP |
3551 | .PP |
3509 | then there is no memory leak. Similarly, under some circumstances, |
3552 | Then there is no memory leak. Similarly, under some circumstances, |
3510 | valgrind might report kernel bugs as if it were a bug in libev, or it |
3553 | valgrind might report kernel bugs as if it were a bug in libev, or it |
3511 | might be confused (it is a very good tool, but only a tool). |
3554 | might be confused (it is a very good tool, but only a tool). |
3512 | .PP |
3555 | .PP |
3513 | If you are unsure about something, feel free to contact the mailing list |
3556 | If you are unsure about something, feel free to contact the mailing list |
3514 | with the full valgrind report and an explanation on why you think this is |
3557 | with the full valgrind report and an explanation on why you think this is |
… | |
… | |
3522 | .IX Header "AUTHOR" |
3565 | .IX Header "AUTHOR" |
3523 | Marc Lehmann <libev@schmorp.de>. |
3566 | Marc Lehmann <libev@schmorp.de>. |
3524 | .SH "POD ERRORS" |
3567 | .SH "POD ERRORS" |
3525 | .IX Header "POD ERRORS" |
3568 | .IX Header "POD ERRORS" |
3526 | Hey! \fBThe above document had some coding errors, which are explained below:\fR |
3569 | Hey! \fBThe above document had some coding errors, which are explained below:\fR |
3527 | .IP "Around line 3107:" 4 |
3570 | .IP "Around line 3116:" 4 |
3528 | .IX Item "Around line 3107:" |
3571 | .IX Item "Around line 3116:" |
3529 | You forgot a '=back' before '=head2' |
3572 | You forgot a '=back' before '=head2' |