… | |
… | |
122 | .\} |
122 | .\} |
123 | .rm #[ #] #H #V #F C |
123 | .rm #[ #] #H #V #F C |
124 | .\" ======================================================================== |
124 | .\" ======================================================================== |
125 | .\" |
125 | .\" |
126 | .IX Title "LIBEV 3" |
126 | .IX Title "LIBEV 3" |
127 | .TH LIBEV 3 "2009-12-31" "libev-3.9" "libev - high performance full featured event loop" |
127 | .TH LIBEV 3 "2010-10-25" "libev-4.00" "libev - high performance full featured event loop" |
128 | .\" For nroff, turn off justification. Always turn off hyphenation; it makes |
128 | .\" For nroff, turn off justification. Always turn off hyphenation; it makes |
129 | .\" way too many mistakes in technical documents. |
129 | .\" way too many mistakes in technical documents. |
130 | .if n .ad l |
130 | .if n .ad l |
131 | .nh |
131 | .nh |
132 | .SH "NAME" |
132 | .SH "NAME" |
… | |
… | |
157 | \& puts ("stdin ready"); |
157 | \& puts ("stdin ready"); |
158 | \& // for one\-shot events, one must manually stop the watcher |
158 | \& // for one\-shot events, one must manually stop the watcher |
159 | \& // with its corresponding stop function. |
159 | \& // with its corresponding stop function. |
160 | \& ev_io_stop (EV_A_ w); |
160 | \& ev_io_stop (EV_A_ w); |
161 | \& |
161 | \& |
162 | \& // this causes all nested ev_loop\*(Aqs to stop iterating |
162 | \& // this causes all nested ev_run\*(Aqs to stop iterating |
163 | \& ev_unloop (EV_A_ EVUNLOOP_ALL); |
163 | \& ev_break (EV_A_ EVBREAK_ALL); |
164 | \& } |
164 | \& } |
165 | \& |
165 | \& |
166 | \& // another callback, this time for a time\-out |
166 | \& // another callback, this time for a time\-out |
167 | \& static void |
167 | \& static void |
168 | \& timeout_cb (EV_P_ ev_timer *w, int revents) |
168 | \& timeout_cb (EV_P_ ev_timer *w, int revents) |
169 | \& { |
169 | \& { |
170 | \& puts ("timeout"); |
170 | \& puts ("timeout"); |
171 | \& // this causes the innermost ev_loop to stop iterating |
171 | \& // this causes the innermost ev_run to stop iterating |
172 | \& ev_unloop (EV_A_ EVUNLOOP_ONE); |
172 | \& ev_break (EV_A_ EVBREAK_ONE); |
173 | \& } |
173 | \& } |
174 | \& |
174 | \& |
175 | \& int |
175 | \& int |
176 | \& main (void) |
176 | \& main (void) |
177 | \& { |
177 | \& { |
178 | \& // use the default event loop unless you have special needs |
178 | \& // use the default event loop unless you have special needs |
179 | \& struct ev_loop *loop = ev_default_loop (0); |
179 | \& struct ev_loop *loop = EV_DEFAULT; |
180 | \& |
180 | \& |
181 | \& // initialise an io watcher, then start it |
181 | \& // initialise an io watcher, then start it |
182 | \& // this one will watch for stdin to become readable |
182 | \& // this one will watch for stdin to become readable |
183 | \& ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ); |
183 | \& ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ); |
184 | \& ev_io_start (loop, &stdin_watcher); |
184 | \& ev_io_start (loop, &stdin_watcher); |
… | |
… | |
187 | \& // simple non\-repeating 5.5 second timeout |
187 | \& // simple non\-repeating 5.5 second timeout |
188 | \& ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.); |
188 | \& ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.); |
189 | \& ev_timer_start (loop, &timeout_watcher); |
189 | \& ev_timer_start (loop, &timeout_watcher); |
190 | \& |
190 | \& |
191 | \& // now wait for events to arrive |
191 | \& // now wait for events to arrive |
192 | \& ev_loop (loop, 0); |
192 | \& ev_run (loop, 0); |
193 | \& |
193 | \& |
194 | \& // unloop was called, so exit |
194 | \& // unloop was called, so exit |
195 | \& return 0; |
195 | \& return 0; |
196 | \& } |
196 | \& } |
197 | .Ve |
197 | .Ve |
… | |
… | |
206 | While this document tries to be as complete as possible in documenting |
206 | While this document tries to be as complete as possible in documenting |
207 | libev, its usage and the rationale behind its design, it is not a tutorial |
207 | libev, its usage and the rationale behind its design, it is not a tutorial |
208 | on event-based programming, nor will it introduce event-based programming |
208 | on event-based programming, nor will it introduce event-based programming |
209 | with libev. |
209 | with libev. |
210 | .PP |
210 | .PP |
211 | Familarity with event based programming techniques in general is assumed |
211 | Familiarity with event based programming techniques in general is assumed |
212 | throughout this document. |
212 | throughout this document. |
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213 | .SH "WHAT TO READ WHEN IN A HURRY" |
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214 | .IX Header "WHAT TO READ WHEN IN A HURRY" |
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215 | This manual tries to be very detailed, but unfortunately, this also makes |
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216 | it very long. If you just want to know the basics of libev, I suggest |
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217 | reading \*(L"\s-1ANATOMY\s0 \s-1OF\s0 A \s-1WATCHER\s0\*(R", then the \*(L"\s-1EXAMPLE\s0 \s-1PROGRAM\s0\*(R" above and |
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218 | look up the missing functions in \*(L"\s-1GLOBAL\s0 \s-1FUNCTIONS\s0\*(R" and the \f(CW\*(C`ev_io\*(C'\fR and |
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219 | \&\f(CW\*(C`ev_timer\*(C'\fR sections in \*(L"\s-1WATCHER\s0 \s-1TYPES\s0\*(R". |
213 | .SH "ABOUT LIBEV" |
220 | .SH "ABOUT LIBEV" |
214 | .IX Header "ABOUT LIBEV" |
221 | .IX Header "ABOUT LIBEV" |
215 | Libev is an event loop: you register interest in certain events (such as a |
222 | Libev is an event loop: you register interest in certain events (such as a |
216 | file descriptor being readable or a timeout occurring), and it will manage |
223 | file descriptor being readable or a timeout occurring), and it will manage |
217 | these event sources and provide your program with events. |
224 | these event sources and provide your program with events. |
… | |
… | |
251 | name \f(CW\*(C`loop\*(C'\fR (which is always of type \f(CW\*(C`struct ev_loop *\*(C'\fR) will not have |
258 | name \f(CW\*(C`loop\*(C'\fR (which is always of type \f(CW\*(C`struct ev_loop *\*(C'\fR) will not have |
252 | this argument. |
259 | this argument. |
253 | .SS "\s-1TIME\s0 \s-1REPRESENTATION\s0" |
260 | .SS "\s-1TIME\s0 \s-1REPRESENTATION\s0" |
254 | .IX Subsection "TIME REPRESENTATION" |
261 | .IX Subsection "TIME REPRESENTATION" |
255 | Libev represents time as a single floating point number, representing |
262 | Libev represents time as a single floating point number, representing |
256 | the (fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere |
263 | the (fractional) number of seconds since the (\s-1POSIX\s0) epoch (in practice |
257 | near the beginning of 1970, details are complicated, don't ask). This |
264 | somewhere near the beginning of 1970, details are complicated, don't |
258 | type is called \f(CW\*(C`ev_tstamp\*(C'\fR, which is what you should use too. It usually |
265 | ask). This type is called \f(CW\*(C`ev_tstamp\*(C'\fR, which is what you should use |
259 | aliases to the \f(CW\*(C`double\*(C'\fR type in C. When you need to do any calculations |
266 | too. It usually aliases to the \f(CW\*(C`double\*(C'\fR type in C. When you need to do |
260 | on it, you should treat it as some floating point value. Unlike the name |
267 | any calculations on it, you should treat it as some floating point value. |
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268 | .PP |
261 | component \f(CW\*(C`stamp\*(C'\fR might indicate, it is also used for time differences |
269 | Unlike the name component \f(CW\*(C`stamp\*(C'\fR might indicate, it is also used for |
262 | throughout libev. |
270 | time differences (e.g. delays) throughout libev. |
263 | .SH "ERROR HANDLING" |
271 | .SH "ERROR HANDLING" |
264 | .IX Header "ERROR HANDLING" |
272 | .IX Header "ERROR HANDLING" |
265 | Libev knows three classes of errors: operating system errors, usage errors |
273 | Libev knows three classes of errors: operating system errors, usage errors |
266 | and internal errors (bugs). |
274 | and internal errors (bugs). |
267 | .PP |
275 | .PP |
… | |
… | |
285 | library in any way. |
293 | library in any way. |
286 | .IP "ev_tstamp ev_time ()" 4 |
294 | .IP "ev_tstamp ev_time ()" 4 |
287 | .IX Item "ev_tstamp ev_time ()" |
295 | .IX Item "ev_tstamp ev_time ()" |
288 | Returns the current time as libev would use it. Please note that the |
296 | Returns the current time as libev would use it. Please note that the |
289 | \&\f(CW\*(C`ev_now\*(C'\fR function is usually faster and also often returns the timestamp |
297 | \&\f(CW\*(C`ev_now\*(C'\fR function is usually faster and also often returns the timestamp |
290 | you actually want to know. |
298 | you actually want to know. Also interesting is the combination of |
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299 | \&\f(CW\*(C`ev_update_now\*(C'\fR and \f(CW\*(C`ev_now\*(C'\fR. |
291 | .IP "ev_sleep (ev_tstamp interval)" 4 |
300 | .IP "ev_sleep (ev_tstamp interval)" 4 |
292 | .IX Item "ev_sleep (ev_tstamp interval)" |
301 | .IX Item "ev_sleep (ev_tstamp interval)" |
293 | Sleep for the given interval: The current thread will be blocked until |
302 | Sleep for the given interval: The current thread will be blocked until |
294 | either it is interrupted or the given time interval has passed. Basically |
303 | either it is interrupted or the given time interval has passed. Basically |
295 | this is a sub-second-resolution \f(CW\*(C`sleep ()\*(C'\fR. |
304 | this is a sub-second-resolution \f(CW\*(C`sleep ()\*(C'\fR. |
… | |
… | |
312 | as this indicates an incompatible change. Minor versions are usually |
321 | as this indicates an incompatible change. Minor versions are usually |
313 | compatible to older versions, so a larger minor version alone is usually |
322 | compatible to older versions, so a larger minor version alone is usually |
314 | not a problem. |
323 | not a problem. |
315 | .Sp |
324 | .Sp |
316 | Example: Make sure we haven't accidentally been linked against the wrong |
325 | Example: Make sure we haven't accidentally been linked against the wrong |
317 | version. |
326 | version (note, however, that this will not detect other \s-1ABI\s0 mismatches, |
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327 | such as \s-1LFS\s0 or reentrancy). |
318 | .Sp |
328 | .Sp |
319 | .Vb 3 |
329 | .Vb 3 |
320 | \& assert (("libev version mismatch", |
330 | \& assert (("libev version mismatch", |
321 | \& ev_version_major () == EV_VERSION_MAJOR |
331 | \& ev_version_major () == EV_VERSION_MAJOR |
322 | \& && ev_version_minor () >= EV_VERSION_MINOR)); |
332 | \& && ev_version_minor () >= EV_VERSION_MINOR)); |
… | |
… | |
335 | \& assert (("sorry, no epoll, no sex", |
345 | \& assert (("sorry, no epoll, no sex", |
336 | \& ev_supported_backends () & EVBACKEND_EPOLL)); |
346 | \& ev_supported_backends () & EVBACKEND_EPOLL)); |
337 | .Ve |
347 | .Ve |
338 | .IP "unsigned int ev_recommended_backends ()" 4 |
348 | .IP "unsigned int ev_recommended_backends ()" 4 |
339 | .IX Item "unsigned int ev_recommended_backends ()" |
349 | .IX Item "unsigned int ev_recommended_backends ()" |
340 | Return the set of all backends compiled into this binary of libev and also |
350 | Return the set of all backends compiled into this binary of libev and |
341 | recommended for this platform. This set is often smaller than the one |
351 | also recommended for this platform, meaning it will work for most file |
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352 | descriptor types. This set is often smaller than the one returned by |
342 | returned by \f(CW\*(C`ev_supported_backends\*(C'\fR, as for example kqueue is broken on |
353 | \&\f(CW\*(C`ev_supported_backends\*(C'\fR, as for example kqueue is broken on most BSDs |
343 | most BSDs and will not be auto-detected unless you explicitly request it |
354 | and will not be auto-detected unless you explicitly request it (assuming |
344 | (assuming you know what you are doing). This is the set of backends that |
355 | you know what you are doing). This is the set of backends that libev will |
345 | libev will probe for if you specify no backends explicitly. |
356 | probe for if you specify no backends explicitly. |
346 | .IP "unsigned int ev_embeddable_backends ()" 4 |
357 | .IP "unsigned int ev_embeddable_backends ()" 4 |
347 | .IX Item "unsigned int ev_embeddable_backends ()" |
358 | .IX Item "unsigned int ev_embeddable_backends ()" |
348 | Returns the set of backends that are embeddable in other event loops. This |
359 | Returns the set of backends that are embeddable in other event loops. This |
349 | is the theoretical, all-platform, value. To find which backends |
360 | value is platform-specific but can include backends not available on the |
350 | might be supported on the current system, you would need to look at |
361 | current system. To find which embeddable backends might be supported on |
351 | \&\f(CW\*(C`ev_embeddable_backends () & ev_supported_backends ()\*(C'\fR, likewise for |
362 | the current system, you would need to look at \f(CW\*(C`ev_embeddable_backends () |
352 | recommended ones. |
363 | & ev_supported_backends ()\*(C'\fR, likewise for recommended ones. |
353 | .Sp |
364 | .Sp |
354 | See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
365 | See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
355 | .IP "ev_set_allocator (void *(*cb)(void *ptr, long size)) [\s-1NOT\s0 \s-1REENTRANT\s0]" 4 |
366 | .IP "ev_set_allocator (void *(*cb)(void *ptr, long size)) [\s-1NOT\s0 \s-1REENTRANT\s0]" 4 |
356 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size)) [NOT REENTRANT]" |
367 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size)) [NOT REENTRANT]" |
357 | Sets the allocation function to use (the prototype is similar \- the |
368 | Sets the allocation function to use (the prototype is similar \- the |
… | |
… | |
410 | \& } |
421 | \& } |
411 | \& |
422 | \& |
412 | \& ... |
423 | \& ... |
413 | \& ev_set_syserr_cb (fatal_error); |
424 | \& ev_set_syserr_cb (fatal_error); |
414 | .Ve |
425 | .Ve |
415 | .SH "FUNCTIONS CONTROLLING THE EVENT LOOP" |
426 | .SH "FUNCTIONS CONTROLLING EVENT LOOPS" |
416 | .IX Header "FUNCTIONS CONTROLLING THE EVENT LOOP" |
427 | .IX Header "FUNCTIONS CONTROLLING EVENT LOOPS" |
417 | An event loop is described by a \f(CW\*(C`struct ev_loop *\*(C'\fR (the \f(CW\*(C`struct\*(C'\fR |
428 | An event loop is described by a \f(CW\*(C`struct ev_loop *\*(C'\fR (the \f(CW\*(C`struct\*(C'\fR is |
418 | is \fInot\fR optional in this case, as there is also an \f(CW\*(C`ev_loop\*(C'\fR |
429 | \&\fInot\fR optional in this case unless libev 3 compatibility is disabled, as |
419 | \&\fIfunction\fR). |
430 | libev 3 had an \f(CW\*(C`ev_loop\*(C'\fR function colliding with the struct name). |
420 | .PP |
431 | .PP |
421 | The library knows two types of such loops, the \fIdefault\fR loop, which |
432 | The library knows two types of such loops, the \fIdefault\fR loop, which |
422 | supports signals and child events, and dynamically created loops which do |
433 | supports child process events, and dynamically created event loops which |
423 | not. |
434 | do not. |
424 | .IP "struct ev_loop *ev_default_loop (unsigned int flags)" 4 |
435 | .IP "struct ev_loop *ev_default_loop (unsigned int flags)" 4 |
425 | .IX Item "struct ev_loop *ev_default_loop (unsigned int flags)" |
436 | .IX Item "struct ev_loop *ev_default_loop (unsigned int flags)" |
426 | This will initialise the default event loop if it hasn't been initialised |
437 | This returns the \*(L"default\*(R" event loop object, which is what you should |
427 | yet and return it. If the default loop could not be initialised, returns |
438 | normally use when you just need \*(L"the event loop\*(R". Event loop objects and |
428 | false. If it already was initialised it simply returns it (and ignores the |
439 | the \f(CW\*(C`flags\*(C'\fR parameter are described in more detail in the entry for |
429 | flags. If that is troubling you, check \f(CW\*(C`ev_backend ()\*(C'\fR afterwards). |
440 | \&\f(CW\*(C`ev_loop_new\*(C'\fR. |
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441 | .Sp |
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442 | If the default loop is already initialised then this function simply |
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443 | returns it (and ignores the flags. If that is troubling you, check |
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444 | \&\f(CW\*(C`ev_backend ()\*(C'\fR afterwards). Otherwise it will create it with the given |
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445 | flags, which should almost always be \f(CW0\fR, unless the caller is also the |
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446 | one calling \f(CW\*(C`ev_run\*(C'\fR or otherwise qualifies as \*(L"the main program\*(R". |
430 | .Sp |
447 | .Sp |
431 | If you don't know what event loop to use, use the one returned from this |
448 | If you don't know what event loop to use, use the one returned from this |
432 | function. |
449 | function (or via the \f(CW\*(C`EV_DEFAULT\*(C'\fR macro). |
433 | .Sp |
450 | .Sp |
434 | Note that this function is \fInot\fR thread-safe, so if you want to use it |
451 | Note that this function is \fInot\fR thread-safe, so if you want to use it |
435 | from multiple threads, you have to lock (note also that this is unlikely, |
452 | from multiple threads, you have to employ some kind of mutex (note also |
436 | as loops cannot be shared easily between threads anyway). |
453 | that this case is unlikely, as loops cannot be shared easily between |
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454 | threads anyway). |
437 | .Sp |
455 | .Sp |
438 | The default loop is the only loop that can handle \f(CW\*(C`ev_signal\*(C'\fR and |
456 | The default loop is the only loop that can handle \f(CW\*(C`ev_child\*(C'\fR watchers, |
439 | \&\f(CW\*(C`ev_child\*(C'\fR watchers, and to do this, it always registers a handler |
457 | and to do this, it always registers a handler for \f(CW\*(C`SIGCHLD\*(C'\fR. If this is |
440 | for \f(CW\*(C`SIGCHLD\*(C'\fR. If this is a problem for your application you can either |
458 | a problem for your application you can either create a dynamic loop with |
441 | create a dynamic loop with \f(CW\*(C`ev_loop_new\*(C'\fR that doesn't do that, or you |
459 | \&\f(CW\*(C`ev_loop_new\*(C'\fR which doesn't do that, or you can simply overwrite the |
442 | can simply overwrite the \f(CW\*(C`SIGCHLD\*(C'\fR signal handler \fIafter\fR calling |
460 | \&\f(CW\*(C`SIGCHLD\*(C'\fR signal handler \fIafter\fR calling \f(CW\*(C`ev_default_init\*(C'\fR. |
443 | \&\f(CW\*(C`ev_default_init\*(C'\fR. |
461 | .Sp |
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462 | Example: This is the most typical usage. |
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463 | .Sp |
|
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464 | .Vb 2 |
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465 | \& if (!ev_default_loop (0)) |
|
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466 | \& fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?"); |
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467 | .Ve |
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468 | .Sp |
|
|
469 | Example: Restrict libev to the select and poll backends, and do not allow |
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470 | environment settings to be taken into account: |
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471 | .Sp |
|
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472 | .Vb 1 |
|
|
473 | \& ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV); |
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474 | .Ve |
|
|
475 | .IP "struct ev_loop *ev_loop_new (unsigned int flags)" 4 |
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476 | .IX Item "struct ev_loop *ev_loop_new (unsigned int flags)" |
|
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477 | This will create and initialise a new event loop object. If the loop |
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478 | could not be initialised, returns false. |
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479 | .Sp |
|
|
480 | Note that this function \fIis\fR thread-safe, and one common way to use |
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|
481 | libev with threads is indeed to create one loop per thread, and using the |
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482 | default loop in the \*(L"main\*(R" or \*(L"initial\*(R" thread. |
444 | .Sp |
483 | .Sp |
445 | The flags argument can be used to specify special behaviour or specific |
484 | The flags argument can be used to specify special behaviour or specific |
446 | backends to use, and is usually specified as \f(CW0\fR (or \f(CW\*(C`EVFLAG_AUTO\*(C'\fR). |
485 | backends to use, and is usually specified as \f(CW0\fR (or \f(CW\*(C`EVFLAG_AUTO\*(C'\fR). |
447 | .Sp |
486 | .Sp |
448 | The following flags are supported: |
487 | The following flags are supported: |
… | |
… | |
462 | useful to try out specific backends to test their performance, or to work |
501 | useful to try out specific backends to test their performance, or to work |
463 | around bugs. |
502 | around bugs. |
464 | .ie n .IP """EVFLAG_FORKCHECK""" 4 |
503 | .ie n .IP """EVFLAG_FORKCHECK""" 4 |
465 | .el .IP "\f(CWEVFLAG_FORKCHECK\fR" 4 |
504 | .el .IP "\f(CWEVFLAG_FORKCHECK\fR" 4 |
466 | .IX Item "EVFLAG_FORKCHECK" |
505 | .IX Item "EVFLAG_FORKCHECK" |
467 | Instead of calling \f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR manually after |
506 | Instead of calling \f(CW\*(C`ev_loop_fork\*(C'\fR manually after a fork, you can also |
468 | a fork, you can also make libev check for a fork in each iteration by |
507 | make libev check for a fork in each iteration by enabling this flag. |
469 | enabling this flag. |
|
|
470 | .Sp |
508 | .Sp |
471 | This works by calling \f(CW\*(C`getpid ()\*(C'\fR on every iteration of the loop, |
509 | This works by calling \f(CW\*(C`getpid ()\*(C'\fR on every iteration of the loop, |
472 | and thus this might slow down your event loop if you do a lot of loop |
510 | and thus this might slow down your event loop if you do a lot of loop |
473 | iterations and little real work, but is usually not noticeable (on my |
511 | iterations and little real work, but is usually not noticeable (on my |
474 | GNU/Linux system for example, \f(CW\*(C`getpid\*(C'\fR is actually a simple 5\-insn sequence |
512 | GNU/Linux system for example, \f(CW\*(C`getpid\*(C'\fR is actually a simple 5\-insn sequence |
… | |
… | |
556 | of course \fIdoesn't\fR, and epoll just loves to report events for totally |
594 | of course \fIdoesn't\fR, and epoll just loves to report events for totally |
557 | \&\fIdifferent\fR file descriptors (even already closed ones, so one cannot |
595 | \&\fIdifferent\fR file descriptors (even already closed ones, so one cannot |
558 | even remove them from the set) than registered in the set (especially |
596 | even remove them from the set) than registered in the set (especially |
559 | on \s-1SMP\s0 systems). Libev tries to counter these spurious notifications by |
597 | on \s-1SMP\s0 systems). Libev tries to counter these spurious notifications by |
560 | employing an additional generation counter and comparing that against the |
598 | employing an additional generation counter and comparing that against the |
561 | events to filter out spurious ones, recreating the set when required. |
599 | events to filter out spurious ones, recreating the set when required. Last |
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600 | not least, it also refuses to work with some file descriptors which work |
|
|
601 | perfectly fine with \f(CW\*(C`select\*(C'\fR (files, many character devices...). |
562 | .Sp |
602 | .Sp |
563 | While stopping, setting and starting an I/O watcher in the same iteration |
603 | While stopping, setting and starting an I/O watcher in the same iteration |
564 | will result in some caching, there is still a system call per such |
604 | will result in some caching, there is still a system call per such |
565 | incident (because the same \fIfile descriptor\fR could point to a different |
605 | incident (because the same \fIfile descriptor\fR could point to a different |
566 | \&\fIfile description\fR now), so its best to avoid that. Also, \f(CW\*(C`dup ()\*(C'\fR'ed |
606 | \&\fIfile description\fR now), so its best to avoid that. Also, \f(CW\*(C`dup ()\*(C'\fR'ed |
… | |
… | |
664 | If one or more of the backend flags are or'ed into the flags value, |
704 | If one or more of the backend flags are or'ed into the flags value, |
665 | then only these backends will be tried (in the reverse order as listed |
705 | then only these backends will be tried (in the reverse order as listed |
666 | here). If none are specified, all backends in \f(CW\*(C`ev_recommended_backends |
706 | here). If none are specified, all backends in \f(CW\*(C`ev_recommended_backends |
667 | ()\*(C'\fR will be tried. |
707 | ()\*(C'\fR will be tried. |
668 | .Sp |
708 | .Sp |
669 | Example: This is the most typical usage. |
|
|
670 | .Sp |
|
|
671 | .Vb 2 |
|
|
672 | \& if (!ev_default_loop (0)) |
|
|
673 | \& fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?"); |
|
|
674 | .Ve |
|
|
675 | .Sp |
|
|
676 | Example: Restrict libev to the select and poll backends, and do not allow |
|
|
677 | environment settings to be taken into account: |
|
|
678 | .Sp |
|
|
679 | .Vb 1 |
|
|
680 | \& ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV); |
|
|
681 | .Ve |
|
|
682 | .Sp |
|
|
683 | Example: Use whatever libev has to offer, but make sure that kqueue is |
|
|
684 | used if available (warning, breaks stuff, best use only with your own |
|
|
685 | private event loop and only if you know the \s-1OS\s0 supports your types of |
|
|
686 | fds): |
|
|
687 | .Sp |
|
|
688 | .Vb 1 |
|
|
689 | \& ev_default_loop (ev_recommended_backends () | EVBACKEND_KQUEUE); |
|
|
690 | .Ve |
|
|
691 | .RE |
|
|
692 | .IP "struct ev_loop *ev_loop_new (unsigned int flags)" 4 |
|
|
693 | .IX Item "struct ev_loop *ev_loop_new (unsigned int flags)" |
|
|
694 | Similar to \f(CW\*(C`ev_default_loop\*(C'\fR, but always creates a new event loop that is |
|
|
695 | always distinct from the default loop. Unlike the default loop, it cannot |
|
|
696 | handle signal and child watchers, and attempts to do so will be greeted by |
|
|
697 | undefined behaviour (or a failed assertion if assertions are enabled). |
|
|
698 | .Sp |
|
|
699 | Note that this function \fIis\fR thread-safe, and the recommended way to use |
|
|
700 | libev with threads is indeed to create one loop per thread, and using the |
|
|
701 | default loop in the \*(L"main\*(R" or \*(L"initial\*(R" thread. |
|
|
702 | .Sp |
|
|
703 | Example: Try to create a event loop that uses epoll and nothing else. |
709 | Example: Try to create a event loop that uses epoll and nothing else. |
704 | .Sp |
710 | .Sp |
705 | .Vb 3 |
711 | .Vb 3 |
706 | \& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
712 | \& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
707 | \& if (!epoller) |
713 | \& if (!epoller) |
708 | \& fatal ("no epoll found here, maybe it hides under your chair"); |
714 | \& fatal ("no epoll found here, maybe it hides under your chair"); |
709 | .Ve |
715 | .Ve |
|
|
716 | .Sp |
|
|
717 | Example: Use whatever libev has to offer, but make sure that kqueue is |
|
|
718 | used if available. |
|
|
719 | .Sp |
|
|
720 | .Vb 1 |
|
|
721 | \& struct ev_loop *loop = ev_loop_new (ev_recommended_backends () | EVBACKEND_KQUEUE); |
|
|
722 | .Ve |
|
|
723 | .RE |
710 | .IP "ev_default_destroy ()" 4 |
724 | .IP "ev_loop_destroy (loop)" 4 |
711 | .IX Item "ev_default_destroy ()" |
725 | .IX Item "ev_loop_destroy (loop)" |
712 | Destroys the default loop again (frees all memory and kernel state |
726 | Destroys an event loop object (frees all memory and kernel state |
713 | etc.). None of the active event watchers will be stopped in the normal |
727 | etc.). None of the active event watchers will be stopped in the normal |
714 | sense, so e.g. \f(CW\*(C`ev_is_active\*(C'\fR might still return true. It is your |
728 | sense, so e.g. \f(CW\*(C`ev_is_active\*(C'\fR might still return true. It is your |
715 | responsibility to either stop all watchers cleanly yourself \fIbefore\fR |
729 | responsibility to either stop all watchers cleanly yourself \fIbefore\fR |
716 | calling this function, or cope with the fact afterwards (which is usually |
730 | calling this function, or cope with the fact afterwards (which is usually |
717 | the easiest thing, you can just ignore the watchers and/or \f(CW\*(C`free ()\*(C'\fR them |
731 | the easiest thing, you can just ignore the watchers and/or \f(CW\*(C`free ()\*(C'\fR them |
… | |
… | |
719 | .Sp |
733 | .Sp |
720 | Note that certain global state, such as signal state (and installed signal |
734 | Note that certain global state, such as signal state (and installed signal |
721 | handlers), will not be freed by this function, and related watchers (such |
735 | handlers), will not be freed by this function, and related watchers (such |
722 | as signal and child watchers) would need to be stopped manually. |
736 | as signal and child watchers) would need to be stopped manually. |
723 | .Sp |
737 | .Sp |
724 | In general it is not advisable to call this function except in the |
738 | This function is normally used on loop objects allocated by |
725 | rare occasion where you really need to free e.g. the signal handling |
739 | \&\f(CW\*(C`ev_loop_new\*(C'\fR, but it can also be used on the default loop returned by |
726 | pipe fds. If you need dynamically allocated loops it is better to use |
740 | \&\f(CW\*(C`ev_default_loop\*(C'\fR, in which case it is not thread-safe. |
727 | \&\f(CW\*(C`ev_loop_new\*(C'\fR and \f(CW\*(C`ev_loop_destroy\*(C'\fR. |
|
|
728 | .IP "ev_loop_destroy (loop)" 4 |
|
|
729 | .IX Item "ev_loop_destroy (loop)" |
|
|
730 | Like \f(CW\*(C`ev_default_destroy\*(C'\fR, but destroys an event loop created by an |
|
|
731 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
|
|
732 | .IP "ev_default_fork ()" 4 |
|
|
733 | .IX Item "ev_default_fork ()" |
|
|
734 | This function sets a flag that causes subsequent \f(CW\*(C`ev_loop\*(C'\fR iterations |
|
|
735 | to reinitialise the kernel state for backends that have one. Despite the |
|
|
736 | name, you can call it anytime, but it makes most sense after forking, in |
|
|
737 | the child process (or both child and parent, but that again makes little |
|
|
738 | sense). You \fImust\fR call it in the child before using any of the libev |
|
|
739 | functions, and it will only take effect at the next \f(CW\*(C`ev_loop\*(C'\fR iteration. |
|
|
740 | .Sp |
741 | .Sp |
741 | On the other hand, you only need to call this function in the child |
742 | Note that it is not advisable to call this function on the default loop |
742 | process if and only if you want to use the event library in the child. If |
743 | except in the rare occasion where you really need to free it's resources. |
743 | you just fork+exec, you don't have to call it at all. |
744 | If you need dynamically allocated loops it is better to use \f(CW\*(C`ev_loop_new\*(C'\fR |
744 | .Sp |
745 | and \f(CW\*(C`ev_loop_destroy\*(C'\fR. |
745 | The function itself is quite fast and it's usually not a problem to call |
|
|
746 | it just in case after a fork. To make this easy, the function will fit in |
|
|
747 | quite nicely into a call to \f(CW\*(C`pthread_atfork\*(C'\fR: |
|
|
748 | .Sp |
|
|
749 | .Vb 1 |
|
|
750 | \& pthread_atfork (0, 0, ev_default_fork); |
|
|
751 | .Ve |
|
|
752 | .IP "ev_loop_fork (loop)" 4 |
746 | .IP "ev_loop_fork (loop)" 4 |
753 | .IX Item "ev_loop_fork (loop)" |
747 | .IX Item "ev_loop_fork (loop)" |
754 | Like \f(CW\*(C`ev_default_fork\*(C'\fR, but acts on an event loop created by |
748 | This function sets a flag that causes subsequent \f(CW\*(C`ev_run\*(C'\fR iterations to |
755 | \&\f(CW\*(C`ev_loop_new\*(C'\fR. Yes, you have to call this on every allocated event loop |
749 | reinitialise the kernel state for backends that have one. Despite the |
756 | after fork that you want to re-use in the child, and how you do this is |
750 | name, you can call it anytime, but it makes most sense after forking, in |
757 | entirely your own problem. |
751 | the child process. You \fImust\fR call it (or use \f(CW\*(C`EVFLAG_FORKCHECK\*(C'\fR) in the |
|
|
752 | child before resuming or calling \f(CW\*(C`ev_run\*(C'\fR. |
|
|
753 | .Sp |
|
|
754 | Again, you \fIhave\fR to call it on \fIany\fR loop that you want to re-use after |
|
|
755 | a fork, \fIeven if you do not plan to use the loop in the parent\fR. This is |
|
|
756 | because some kernel interfaces *cough* \fIkqueue\fR *cough* do funny things |
|
|
757 | during fork. |
|
|
758 | .Sp |
|
|
759 | On the other hand, you only need to call this function in the child |
|
|
760 | process if and only if you want to use the event loop in the child. If |
|
|
761 | you just fork+exec or create a new loop in the child, you don't have to |
|
|
762 | call it at all (in fact, \f(CW\*(C`epoll\*(C'\fR is so badly broken that it makes a |
|
|
763 | difference, but libev will usually detect this case on its own and do a |
|
|
764 | costly reset of the backend). |
|
|
765 | .Sp |
|
|
766 | The function itself is quite fast and it's usually not a problem to call |
|
|
767 | it just in case after a fork. |
|
|
768 | .Sp |
|
|
769 | Example: Automate calling \f(CW\*(C`ev_loop_fork\*(C'\fR on the default loop when |
|
|
770 | using pthreads. |
|
|
771 | .Sp |
|
|
772 | .Vb 5 |
|
|
773 | \& static void |
|
|
774 | \& post_fork_child (void) |
|
|
775 | \& { |
|
|
776 | \& ev_loop_fork (EV_DEFAULT); |
|
|
777 | \& } |
|
|
778 | \& |
|
|
779 | \& ... |
|
|
780 | \& pthread_atfork (0, 0, post_fork_child); |
|
|
781 | .Ve |
758 | .IP "int ev_is_default_loop (loop)" 4 |
782 | .IP "int ev_is_default_loop (loop)" 4 |
759 | .IX Item "int ev_is_default_loop (loop)" |
783 | .IX Item "int ev_is_default_loop (loop)" |
760 | Returns true when the given loop is, in fact, the default loop, and false |
784 | Returns true when the given loop is, in fact, the default loop, and false |
761 | otherwise. |
785 | otherwise. |
762 | .IP "unsigned int ev_loop_count (loop)" 4 |
786 | .IP "unsigned int ev_iteration (loop)" 4 |
763 | .IX Item "unsigned int ev_loop_count (loop)" |
787 | .IX Item "unsigned int ev_iteration (loop)" |
764 | Returns the count of loop iterations for the loop, which is identical to |
788 | Returns the current iteration count for the event loop, which is identical |
765 | the number of times libev did poll for new events. It starts at \f(CW0\fR and |
789 | to the number of times libev did poll for new events. It starts at \f(CW0\fR |
766 | happily wraps around with enough iterations. |
790 | and happily wraps around with enough iterations. |
767 | .Sp |
791 | .Sp |
768 | This value can sometimes be useful as a generation counter of sorts (it |
792 | This value can sometimes be useful as a generation counter of sorts (it |
769 | \&\*(L"ticks\*(R" the number of loop iterations), as it roughly corresponds with |
793 | \&\*(L"ticks\*(R" the number of loop iterations), as it roughly corresponds with |
770 | \&\f(CW\*(C`ev_prepare\*(C'\fR and \f(CW\*(C`ev_check\*(C'\fR calls. |
794 | \&\f(CW\*(C`ev_prepare\*(C'\fR and \f(CW\*(C`ev_check\*(C'\fR calls \- and is incremented between the |
|
|
795 | prepare and check phases. |
771 | .IP "unsigned int ev_loop_depth (loop)" 4 |
796 | .IP "unsigned int ev_depth (loop)" 4 |
772 | .IX Item "unsigned int ev_loop_depth (loop)" |
797 | .IX Item "unsigned int ev_depth (loop)" |
773 | Returns the number of times \f(CW\*(C`ev_loop\*(C'\fR was entered minus the number of |
798 | Returns the number of times \f(CW\*(C`ev_run\*(C'\fR was entered minus the number of |
774 | times \f(CW\*(C`ev_loop\*(C'\fR was exited, in other words, the recursion depth. |
799 | times \f(CW\*(C`ev_run\*(C'\fR was exited, in other words, the recursion depth. |
775 | .Sp |
800 | .Sp |
776 | Outside \f(CW\*(C`ev_loop\*(C'\fR, this number is zero. In a callback, this number is |
801 | Outside \f(CW\*(C`ev_run\*(C'\fR, this number is zero. In a callback, this number is |
777 | \&\f(CW1\fR, unless \f(CW\*(C`ev_loop\*(C'\fR was invoked recursively (or from another thread), |
802 | \&\f(CW1\fR, unless \f(CW\*(C`ev_run\*(C'\fR was invoked recursively (or from another thread), |
778 | in which case it is higher. |
803 | in which case it is higher. |
779 | .Sp |
804 | .Sp |
780 | Leaving \f(CW\*(C`ev_loop\*(C'\fR abnormally (setjmp/longjmp, cancelling the thread |
805 | Leaving \f(CW\*(C`ev_run\*(C'\fR abnormally (setjmp/longjmp, cancelling the thread |
781 | etc.), doesn't count as exit. |
806 | etc.), doesn't count as \*(L"exit\*(R" \- consider this as a hint to avoid such |
|
|
807 | ungentleman-like behaviour unless it's really convenient. |
782 | .IP "unsigned int ev_backend (loop)" 4 |
808 | .IP "unsigned int ev_backend (loop)" 4 |
783 | .IX Item "unsigned int ev_backend (loop)" |
809 | .IX Item "unsigned int ev_backend (loop)" |
784 | Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in |
810 | Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in |
785 | use. |
811 | use. |
786 | .IP "ev_tstamp ev_now (loop)" 4 |
812 | .IP "ev_tstamp ev_now (loop)" 4 |
… | |
… | |
792 | event occurring (or more correctly, libev finding out about it). |
818 | event occurring (or more correctly, libev finding out about it). |
793 | .IP "ev_now_update (loop)" 4 |
819 | .IP "ev_now_update (loop)" 4 |
794 | .IX Item "ev_now_update (loop)" |
820 | .IX Item "ev_now_update (loop)" |
795 | Establishes the current time by querying the kernel, updating the time |
821 | Establishes the current time by querying the kernel, updating the time |
796 | returned by \f(CW\*(C`ev_now ()\*(C'\fR in the progress. This is a costly operation and |
822 | returned by \f(CW\*(C`ev_now ()\*(C'\fR in the progress. This is a costly operation and |
797 | is usually done automatically within \f(CW\*(C`ev_loop ()\*(C'\fR. |
823 | is usually done automatically within \f(CW\*(C`ev_run ()\*(C'\fR. |
798 | .Sp |
824 | .Sp |
799 | This function is rarely useful, but when some event callback runs for a |
825 | This function is rarely useful, but when some event callback runs for a |
800 | very long time without entering the event loop, updating libev's idea of |
826 | very long time without entering the event loop, updating libev's idea of |
801 | the current time is a good idea. |
827 | the current time is a good idea. |
802 | .Sp |
828 | .Sp |
… | |
… | |
805 | .IX Item "ev_suspend (loop)" |
831 | .IX Item "ev_suspend (loop)" |
806 | .PD 0 |
832 | .PD 0 |
807 | .IP "ev_resume (loop)" 4 |
833 | .IP "ev_resume (loop)" 4 |
808 | .IX Item "ev_resume (loop)" |
834 | .IX Item "ev_resume (loop)" |
809 | .PD |
835 | .PD |
810 | These two functions suspend and resume a loop, for use when the loop is |
836 | These two functions suspend and resume an event loop, for use when the |
811 | not used for a while and timeouts should not be processed. |
837 | loop is not used for a while and timeouts should not be processed. |
812 | .Sp |
838 | .Sp |
813 | A typical use case would be an interactive program such as a game: When |
839 | A typical use case would be an interactive program such as a game: When |
814 | the user presses \f(CW\*(C`^Z\*(C'\fR to suspend the game and resumes it an hour later it |
840 | the user presses \f(CW\*(C`^Z\*(C'\fR to suspend the game and resumes it an hour later it |
815 | would be best to handle timeouts as if no time had actually passed while |
841 | would be best to handle timeouts as if no time had actually passed while |
816 | the program was suspended. This can be achieved by calling \f(CW\*(C`ev_suspend\*(C'\fR |
842 | the program was suspended. This can be achieved by calling \f(CW\*(C`ev_suspend\*(C'\fR |
… | |
… | |
818 | \&\f(CW\*(C`ev_resume\*(C'\fR directly afterwards to resume timer processing. |
844 | \&\f(CW\*(C`ev_resume\*(C'\fR directly afterwards to resume timer processing. |
819 | .Sp |
845 | .Sp |
820 | Effectively, all \f(CW\*(C`ev_timer\*(C'\fR watchers will be delayed by the time spend |
846 | Effectively, all \f(CW\*(C`ev_timer\*(C'\fR watchers will be delayed by the time spend |
821 | between \f(CW\*(C`ev_suspend\*(C'\fR and \f(CW\*(C`ev_resume\*(C'\fR, and all \f(CW\*(C`ev_periodic\*(C'\fR watchers |
847 | between \f(CW\*(C`ev_suspend\*(C'\fR and \f(CW\*(C`ev_resume\*(C'\fR, and all \f(CW\*(C`ev_periodic\*(C'\fR watchers |
822 | will be rescheduled (that is, they will lose any events that would have |
848 | will be rescheduled (that is, they will lose any events that would have |
823 | occured while suspended). |
849 | occurred while suspended). |
824 | .Sp |
850 | .Sp |
825 | After calling \f(CW\*(C`ev_suspend\*(C'\fR you \fBmust not\fR call \fIany\fR function on the |
851 | After calling \f(CW\*(C`ev_suspend\*(C'\fR you \fBmust not\fR call \fIany\fR function on the |
826 | given loop other than \f(CW\*(C`ev_resume\*(C'\fR, and you \fBmust not\fR call \f(CW\*(C`ev_resume\*(C'\fR |
852 | given loop other than \f(CW\*(C`ev_resume\*(C'\fR, and you \fBmust not\fR call \f(CW\*(C`ev_resume\*(C'\fR |
827 | without a previous call to \f(CW\*(C`ev_suspend\*(C'\fR. |
853 | without a previous call to \f(CW\*(C`ev_suspend\*(C'\fR. |
828 | .Sp |
854 | .Sp |
829 | Calling \f(CW\*(C`ev_suspend\*(C'\fR/\f(CW\*(C`ev_resume\*(C'\fR has the side effect of updating the |
855 | Calling \f(CW\*(C`ev_suspend\*(C'\fR/\f(CW\*(C`ev_resume\*(C'\fR has the side effect of updating the |
830 | event loop time (see \f(CW\*(C`ev_now_update\*(C'\fR). |
856 | event loop time (see \f(CW\*(C`ev_now_update\*(C'\fR). |
831 | .IP "ev_loop (loop, int flags)" 4 |
857 | .IP "ev_run (loop, int flags)" 4 |
832 | .IX Item "ev_loop (loop, int flags)" |
858 | .IX Item "ev_run (loop, int flags)" |
833 | Finally, this is it, the event handler. This function usually is called |
859 | Finally, this is it, the event handler. This function usually is called |
834 | after you have initialised all your watchers and you want to start |
860 | after you have initialised all your watchers and you want to start |
835 | handling events. |
861 | handling events. It will ask the operating system for any new events, call |
|
|
862 | the watcher callbacks, an then repeat the whole process indefinitely: This |
|
|
863 | is why event loops are called \fIloops\fR. |
836 | .Sp |
864 | .Sp |
837 | If the flags argument is specified as \f(CW0\fR, it will not return until |
865 | If the flags argument is specified as \f(CW0\fR, it will keep handling events |
838 | either no event watchers are active anymore or \f(CW\*(C`ev_unloop\*(C'\fR was called. |
866 | until either no event watchers are active anymore or \f(CW\*(C`ev_break\*(C'\fR was |
|
|
867 | called. |
839 | .Sp |
868 | .Sp |
840 | Please note that an explicit \f(CW\*(C`ev_unloop\*(C'\fR is usually better than |
869 | Please note that an explicit \f(CW\*(C`ev_break\*(C'\fR is usually better than |
841 | relying on all watchers to be stopped when deciding when a program has |
870 | relying on all watchers to be stopped when deciding when a program has |
842 | finished (especially in interactive programs), but having a program |
871 | finished (especially in interactive programs), but having a program |
843 | that automatically loops as long as it has to and no longer by virtue |
872 | that automatically loops as long as it has to and no longer by virtue |
844 | of relying on its watchers stopping correctly, that is truly a thing of |
873 | of relying on its watchers stopping correctly, that is truly a thing of |
845 | beauty. |
874 | beauty. |
846 | .Sp |
875 | .Sp |
847 | A flags value of \f(CW\*(C`EVLOOP_NONBLOCK\*(C'\fR will look for new events, will handle |
876 | A flags value of \f(CW\*(C`EVRUN_NOWAIT\*(C'\fR will look for new events, will handle |
848 | those events and any already outstanding ones, but will not block your |
877 | those events and any already outstanding ones, but will not wait and |
849 | process in case there are no events and will return after one iteration of |
878 | block your process in case there are no events and will return after one |
850 | the loop. |
879 | iteration of the loop. This is sometimes useful to poll and handle new |
|
|
880 | events while doing lengthy calculations, to keep the program responsive. |
851 | .Sp |
881 | .Sp |
852 | A flags value of \f(CW\*(C`EVLOOP_ONESHOT\*(C'\fR will look for new events (waiting if |
882 | A flags value of \f(CW\*(C`EVRUN_ONCE\*(C'\fR will look for new events (waiting if |
853 | necessary) and will handle those and any already outstanding ones. It |
883 | necessary) and will handle those and any already outstanding ones. It |
854 | will block your process until at least one new event arrives (which could |
884 | will block your process until at least one new event arrives (which could |
855 | be an event internal to libev itself, so there is no guarantee that a |
885 | be an event internal to libev itself, so there is no guarantee that a |
856 | user-registered callback will be called), and will return after one |
886 | user-registered callback will be called), and will return after one |
857 | iteration of the loop. |
887 | iteration of the loop. |
858 | .Sp |
888 | .Sp |
859 | This is useful if you are waiting for some external event in conjunction |
889 | This is useful if you are waiting for some external event in conjunction |
860 | with something not expressible using other libev watchers (i.e. "roll your |
890 | with something not expressible using other libev watchers (i.e. "roll your |
861 | own \f(CW\*(C`ev_loop\*(C'\fR"). However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is |
891 | own \f(CW\*(C`ev_run\*(C'\fR"). However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is |
862 | usually a better approach for this kind of thing. |
892 | usually a better approach for this kind of thing. |
863 | .Sp |
893 | .Sp |
864 | Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does: |
894 | Here are the gory details of what \f(CW\*(C`ev_run\*(C'\fR does: |
865 | .Sp |
895 | .Sp |
866 | .Vb 10 |
896 | .Vb 10 |
|
|
897 | \& \- Increment loop depth. |
|
|
898 | \& \- Reset the ev_break status. |
867 | \& \- Before the first iteration, call any pending watchers. |
899 | \& \- Before the first iteration, call any pending watchers. |
|
|
900 | \& LOOP: |
868 | \& * If EVFLAG_FORKCHECK was used, check for a fork. |
901 | \& \- If EVFLAG_FORKCHECK was used, check for a fork. |
869 | \& \- If a fork was detected (by any means), queue and call all fork watchers. |
902 | \& \- If a fork was detected (by any means), queue and call all fork watchers. |
870 | \& \- Queue and call all prepare watchers. |
903 | \& \- Queue and call all prepare watchers. |
|
|
904 | \& \- If ev_break was called, goto FINISH. |
871 | \& \- If we have been forked, detach and recreate the kernel state |
905 | \& \- If we have been forked, detach and recreate the kernel state |
872 | \& as to not disturb the other process. |
906 | \& as to not disturb the other process. |
873 | \& \- Update the kernel state with all outstanding changes. |
907 | \& \- Update the kernel state with all outstanding changes. |
874 | \& \- Update the "event loop time" (ev_now ()). |
908 | \& \- Update the "event loop time" (ev_now ()). |
875 | \& \- Calculate for how long to sleep or block, if at all |
909 | \& \- Calculate for how long to sleep or block, if at all |
876 | \& (active idle watchers, EVLOOP_NONBLOCK or not having |
910 | \& (active idle watchers, EVRUN_NOWAIT or not having |
877 | \& any active watchers at all will result in not sleeping). |
911 | \& any active watchers at all will result in not sleeping). |
878 | \& \- Sleep if the I/O and timer collect interval say so. |
912 | \& \- Sleep if the I/O and timer collect interval say so. |
|
|
913 | \& \- Increment loop iteration counter. |
879 | \& \- Block the process, waiting for any events. |
914 | \& \- Block the process, waiting for any events. |
880 | \& \- Queue all outstanding I/O (fd) events. |
915 | \& \- Queue all outstanding I/O (fd) events. |
881 | \& \- Update the "event loop time" (ev_now ()), and do time jump adjustments. |
916 | \& \- Update the "event loop time" (ev_now ()), and do time jump adjustments. |
882 | \& \- Queue all expired timers. |
917 | \& \- Queue all expired timers. |
883 | \& \- Queue all expired periodics. |
918 | \& \- Queue all expired periodics. |
884 | \& \- Unless any events are pending now, queue all idle watchers. |
919 | \& \- Queue all idle watchers with priority higher than that of pending events. |
885 | \& \- Queue all check watchers. |
920 | \& \- Queue all check watchers. |
886 | \& \- Call all queued watchers in reverse order (i.e. check watchers first). |
921 | \& \- Call all queued watchers in reverse order (i.e. check watchers first). |
887 | \& Signals and child watchers are implemented as I/O watchers, and will |
922 | \& Signals and child watchers are implemented as I/O watchers, and will |
888 | \& be handled here by queueing them when their watcher gets executed. |
923 | \& be handled here by queueing them when their watcher gets executed. |
889 | \& \- If ev_unloop has been called, or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
924 | \& \- If ev_break has been called, or EVRUN_ONCE or EVRUN_NOWAIT |
890 | \& were used, or there are no active watchers, return, otherwise |
925 | \& were used, or there are no active watchers, goto FINISH, otherwise |
891 | \& continue with step *. |
926 | \& continue with step LOOP. |
|
|
927 | \& FINISH: |
|
|
928 | \& \- Reset the ev_break status iff it was EVBREAK_ONE. |
|
|
929 | \& \- Decrement the loop depth. |
|
|
930 | \& \- Return. |
892 | .Ve |
931 | .Ve |
893 | .Sp |
932 | .Sp |
894 | Example: Queue some jobs and then loop until no events are outstanding |
933 | Example: Queue some jobs and then loop until no events are outstanding |
895 | anymore. |
934 | anymore. |
896 | .Sp |
935 | .Sp |
897 | .Vb 4 |
936 | .Vb 4 |
898 | \& ... queue jobs here, make sure they register event watchers as long |
937 | \& ... queue jobs here, make sure they register event watchers as long |
899 | \& ... as they still have work to do (even an idle watcher will do..) |
938 | \& ... as they still have work to do (even an idle watcher will do..) |
900 | \& ev_loop (my_loop, 0); |
939 | \& ev_run (my_loop, 0); |
901 | \& ... jobs done or somebody called unloop. yeah! |
940 | \& ... jobs done or somebody called unloop. yeah! |
902 | .Ve |
941 | .Ve |
903 | .IP "ev_unloop (loop, how)" 4 |
942 | .IP "ev_break (loop, how)" 4 |
904 | .IX Item "ev_unloop (loop, how)" |
943 | .IX Item "ev_break (loop, how)" |
905 | Can be used to make a call to \f(CW\*(C`ev_loop\*(C'\fR return early (but only after it |
944 | Can be used to make a call to \f(CW\*(C`ev_run\*(C'\fR return early (but only after it |
906 | has processed all outstanding events). The \f(CW\*(C`how\*(C'\fR argument must be either |
945 | has processed all outstanding events). The \f(CW\*(C`how\*(C'\fR argument must be either |
907 | \&\f(CW\*(C`EVUNLOOP_ONE\*(C'\fR, which will make the innermost \f(CW\*(C`ev_loop\*(C'\fR call return, or |
946 | \&\f(CW\*(C`EVBREAK_ONE\*(C'\fR, which will make the innermost \f(CW\*(C`ev_run\*(C'\fR call return, or |
908 | \&\f(CW\*(C`EVUNLOOP_ALL\*(C'\fR, which will make all nested \f(CW\*(C`ev_loop\*(C'\fR calls return. |
947 | \&\f(CW\*(C`EVBREAK_ALL\*(C'\fR, which will make all nested \f(CW\*(C`ev_run\*(C'\fR calls return. |
909 | .Sp |
948 | .Sp |
910 | This \*(L"unloop state\*(R" will be cleared when entering \f(CW\*(C`ev_loop\*(C'\fR again. |
949 | This \*(L"unloop state\*(R" will be cleared when entering \f(CW\*(C`ev_run\*(C'\fR again. |
911 | .Sp |
950 | .Sp |
912 | It is safe to call \f(CW\*(C`ev_unloop\*(C'\fR from otuside any \f(CW\*(C`ev_loop\*(C'\fR calls. |
951 | It is safe to call \f(CW\*(C`ev_break\*(C'\fR from outside any \f(CW\*(C`ev_run\*(C'\fR calls. ##TODO## |
913 | .IP "ev_ref (loop)" 4 |
952 | .IP "ev_ref (loop)" 4 |
914 | .IX Item "ev_ref (loop)" |
953 | .IX Item "ev_ref (loop)" |
915 | .PD 0 |
954 | .PD 0 |
916 | .IP "ev_unref (loop)" 4 |
955 | .IP "ev_unref (loop)" 4 |
917 | .IX Item "ev_unref (loop)" |
956 | .IX Item "ev_unref (loop)" |
918 | .PD |
957 | .PD |
919 | Ref/unref can be used to add or remove a reference count on the event |
958 | Ref/unref can be used to add or remove a reference count on the event |
920 | loop: Every watcher keeps one reference, and as long as the reference |
959 | loop: Every watcher keeps one reference, and as long as the reference |
921 | count is nonzero, \f(CW\*(C`ev_loop\*(C'\fR will not return on its own. |
960 | count is nonzero, \f(CW\*(C`ev_run\*(C'\fR will not return on its own. |
922 | .Sp |
961 | .Sp |
923 | This is useful when you have a watcher that you never intend to |
962 | This is useful when you have a watcher that you never intend to |
924 | unregister, but that nevertheless should not keep \f(CW\*(C`ev_loop\*(C'\fR from |
963 | unregister, but that nevertheless should not keep \f(CW\*(C`ev_run\*(C'\fR from |
925 | returning. In such a case, call \f(CW\*(C`ev_unref\*(C'\fR after starting, and \f(CW\*(C`ev_ref\*(C'\fR |
964 | returning. In such a case, call \f(CW\*(C`ev_unref\*(C'\fR after starting, and \f(CW\*(C`ev_ref\*(C'\fR |
926 | before stopping it. |
965 | before stopping it. |
927 | .Sp |
966 | .Sp |
928 | As an example, libev itself uses this for its internal signal pipe: It |
967 | As an example, libev itself uses this for its internal signal pipe: It |
929 | is not visible to the libev user and should not keep \f(CW\*(C`ev_loop\*(C'\fR from |
968 | is not visible to the libev user and should not keep \f(CW\*(C`ev_run\*(C'\fR from |
930 | exiting if no event watchers registered by it are active. It is also an |
969 | exiting if no event watchers registered by it are active. It is also an |
931 | excellent way to do this for generic recurring timers or from within |
970 | excellent way to do this for generic recurring timers or from within |
932 | third-party libraries. Just remember to \fIunref after start\fR and \fIref |
971 | third-party libraries. Just remember to \fIunref after start\fR and \fIref |
933 | before stop\fR (but only if the watcher wasn't active before, or was active |
972 | before stop\fR (but only if the watcher wasn't active before, or was active |
934 | before, respectively. Note also that libev might stop watchers itself |
973 | before, respectively. Note also that libev might stop watchers itself |
935 | (e.g. non-repeating timers) in which case you have to \f(CW\*(C`ev_ref\*(C'\fR |
974 | (e.g. non-repeating timers) in which case you have to \f(CW\*(C`ev_ref\*(C'\fR |
936 | in the callback). |
975 | in the callback). |
937 | .Sp |
976 | .Sp |
938 | Example: Create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR |
977 | Example: Create a signal watcher, but keep it from keeping \f(CW\*(C`ev_run\*(C'\fR |
939 | running when nothing else is active. |
978 | running when nothing else is active. |
940 | .Sp |
979 | .Sp |
941 | .Vb 4 |
980 | .Vb 4 |
942 | \& ev_signal exitsig; |
981 | \& ev_signal exitsig; |
943 | \& ev_signal_init (&exitsig, sig_cb, SIGINT); |
982 | \& ev_signal_init (&exitsig, sig_cb, SIGINT); |
… | |
… | |
993 | usually doesn't make much sense to set it to a lower value than \f(CW0.01\fR, |
1032 | usually doesn't make much sense to set it to a lower value than \f(CW0.01\fR, |
994 | as this approaches the timing granularity of most systems. Note that if |
1033 | as this approaches the timing granularity of most systems. Note that if |
995 | you do transactions with the outside world and you can't increase the |
1034 | you do transactions with the outside world and you can't increase the |
996 | parallelity, then this setting will limit your transaction rate (if you |
1035 | parallelity, then this setting will limit your transaction rate (if you |
997 | need to poll once per transaction and the I/O collect interval is 0.01, |
1036 | need to poll once per transaction and the I/O collect interval is 0.01, |
998 | then you can't do more than 100 transations per second). |
1037 | then you can't do more than 100 transactions per second). |
999 | .Sp |
1038 | .Sp |
1000 | Setting the \fItimeout collect interval\fR can improve the opportunity for |
1039 | Setting the \fItimeout collect interval\fR can improve the opportunity for |
1001 | saving power, as the program will \*(L"bundle\*(R" timer callback invocations that |
1040 | saving power, as the program will \*(L"bundle\*(R" timer callback invocations that |
1002 | are \*(L"near\*(R" in time together, by delaying some, thus reducing the number of |
1041 | are \*(L"near\*(R" in time together, by delaying some, thus reducing the number of |
1003 | times the process sleeps and wakes up again. Another useful technique to |
1042 | times the process sleeps and wakes up again. Another useful technique to |
… | |
… | |
1012 | \& ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01); |
1051 | \& ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01); |
1013 | .Ve |
1052 | .Ve |
1014 | .IP "ev_invoke_pending (loop)" 4 |
1053 | .IP "ev_invoke_pending (loop)" 4 |
1015 | .IX Item "ev_invoke_pending (loop)" |
1054 | .IX Item "ev_invoke_pending (loop)" |
1016 | This call will simply invoke all pending watchers while resetting their |
1055 | This call will simply invoke all pending watchers while resetting their |
1017 | pending state. Normally, \f(CW\*(C`ev_loop\*(C'\fR does this automatically when required, |
1056 | pending state. Normally, \f(CW\*(C`ev_run\*(C'\fR does this automatically when required, |
1018 | but when overriding the invoke callback this call comes handy. |
1057 | but when overriding the invoke callback this call comes handy. This |
|
|
1058 | function can be invoked from a watcher \- this can be useful for example |
|
|
1059 | when you want to do some lengthy calculation and want to pass further |
|
|
1060 | event handling to another thread (you still have to make sure only one |
|
|
1061 | thread executes within \f(CW\*(C`ev_invoke_pending\*(C'\fR or \f(CW\*(C`ev_run\*(C'\fR of course). |
1019 | .IP "int ev_pending_count (loop)" 4 |
1062 | .IP "int ev_pending_count (loop)" 4 |
1020 | .IX Item "int ev_pending_count (loop)" |
1063 | .IX Item "int ev_pending_count (loop)" |
1021 | Returns the number of pending watchers \- zero indicates that no watchers |
1064 | Returns the number of pending watchers \- zero indicates that no watchers |
1022 | are pending. |
1065 | are pending. |
1023 | .IP "ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(\s-1EV_P\s0))" 4 |
1066 | .IP "ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(\s-1EV_P\s0))" 4 |
1024 | .IX Item "ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))" |
1067 | .IX Item "ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))" |
1025 | This overrides the invoke pending functionality of the loop: Instead of |
1068 | This overrides the invoke pending functionality of the loop: Instead of |
1026 | invoking all pending watchers when there are any, \f(CW\*(C`ev_loop\*(C'\fR will call |
1069 | invoking all pending watchers when there are any, \f(CW\*(C`ev_run\*(C'\fR will call |
1027 | this callback instead. This is useful, for example, when you want to |
1070 | this callback instead. This is useful, for example, when you want to |
1028 | invoke the actual watchers inside another context (another thread etc.). |
1071 | invoke the actual watchers inside another context (another thread etc.). |
1029 | .Sp |
1072 | .Sp |
1030 | If you want to reset the callback, use \f(CW\*(C`ev_invoke_pending\*(C'\fR as new |
1073 | If you want to reset the callback, use \f(CW\*(C`ev_invoke_pending\*(C'\fR as new |
1031 | callback. |
1074 | callback. |
… | |
… | |
1033 | .IX Item "ev_set_loop_release_cb (loop, void (*release)(EV_P), void (*acquire)(EV_P))" |
1076 | .IX Item "ev_set_loop_release_cb (loop, void (*release)(EV_P), void (*acquire)(EV_P))" |
1034 | Sometimes you want to share the same loop between multiple threads. This |
1077 | Sometimes you want to share the same loop between multiple threads. This |
1035 | can be done relatively simply by putting mutex_lock/unlock calls around |
1078 | can be done relatively simply by putting mutex_lock/unlock calls around |
1036 | each call to a libev function. |
1079 | each call to a libev function. |
1037 | .Sp |
1080 | .Sp |
1038 | However, \f(CW\*(C`ev_loop\*(C'\fR can run an indefinite time, so it is not feasible to |
1081 | However, \f(CW\*(C`ev_run\*(C'\fR can run an indefinite time, so it is not feasible |
1039 | wait for it to return. One way around this is to wake up the loop via |
1082 | to wait for it to return. One way around this is to wake up the event |
1040 | \&\f(CW\*(C`ev_unloop\*(C'\fR and \f(CW\*(C`av_async_send\*(C'\fR, another way is to set these \fIrelease\fR |
1083 | loop via \f(CW\*(C`ev_break\*(C'\fR and \f(CW\*(C`av_async_send\*(C'\fR, another way is to set these |
1041 | and \fIacquire\fR callbacks on the loop. |
1084 | \&\fIrelease\fR and \fIacquire\fR callbacks on the loop. |
1042 | .Sp |
1085 | .Sp |
1043 | When set, then \f(CW\*(C`release\*(C'\fR will be called just before the thread is |
1086 | When set, then \f(CW\*(C`release\*(C'\fR will be called just before the thread is |
1044 | suspended waiting for new events, and \f(CW\*(C`acquire\*(C'\fR is called just |
1087 | suspended waiting for new events, and \f(CW\*(C`acquire\*(C'\fR is called just |
1045 | afterwards. |
1088 | afterwards. |
1046 | .Sp |
1089 | .Sp |
… | |
… | |
1049 | .Sp |
1092 | .Sp |
1050 | While event loop modifications are allowed between invocations of |
1093 | While event loop modifications are allowed between invocations of |
1051 | \&\f(CW\*(C`release\*(C'\fR and \f(CW\*(C`acquire\*(C'\fR (that's their only purpose after all), no |
1094 | \&\f(CW\*(C`release\*(C'\fR and \f(CW\*(C`acquire\*(C'\fR (that's their only purpose after all), no |
1052 | modifications done will affect the event loop, i.e. adding watchers will |
1095 | modifications done will affect the event loop, i.e. adding watchers will |
1053 | have no effect on the set of file descriptors being watched, or the time |
1096 | have no effect on the set of file descriptors being watched, or the time |
1054 | waited. Use an \f(CW\*(C`ev_async\*(C'\fR watcher to wake up \f(CW\*(C`ev_loop\*(C'\fR when you want it |
1097 | waited. Use an \f(CW\*(C`ev_async\*(C'\fR watcher to wake up \f(CW\*(C`ev_run\*(C'\fR when you want it |
1055 | to take note of any changes you made. |
1098 | to take note of any changes you made. |
1056 | .Sp |
1099 | .Sp |
1057 | In theory, threads executing \f(CW\*(C`ev_loop\*(C'\fR will be async-cancel safe between |
1100 | In theory, threads executing \f(CW\*(C`ev_run\*(C'\fR will be async-cancel safe between |
1058 | invocations of \f(CW\*(C`release\*(C'\fR and \f(CW\*(C`acquire\*(C'\fR. |
1101 | invocations of \f(CW\*(C`release\*(C'\fR and \f(CW\*(C`acquire\*(C'\fR. |
1059 | .Sp |
1102 | .Sp |
1060 | See also the locking example in the \f(CW\*(C`THREADS\*(C'\fR section later in this |
1103 | See also the locking example in the \f(CW\*(C`THREADS\*(C'\fR section later in this |
1061 | document. |
1104 | document. |
1062 | .IP "ev_set_userdata (loop, void *data)" 4 |
1105 | .IP "ev_set_userdata (loop, void *data)" 4 |
… | |
… | |
1071 | .Sp |
1114 | .Sp |
1072 | These two functions can be used to associate arbitrary data with a loop, |
1115 | These two functions can be used to associate arbitrary data with a loop, |
1073 | and are intended solely for the \f(CW\*(C`invoke_pending_cb\*(C'\fR, \f(CW\*(C`release\*(C'\fR and |
1116 | and are intended solely for the \f(CW\*(C`invoke_pending_cb\*(C'\fR, \f(CW\*(C`release\*(C'\fR and |
1074 | \&\f(CW\*(C`acquire\*(C'\fR callbacks described above, but of course can be (ab\-)used for |
1117 | \&\f(CW\*(C`acquire\*(C'\fR callbacks described above, but of course can be (ab\-)used for |
1075 | any other purpose as well. |
1118 | any other purpose as well. |
1076 | .IP "ev_loop_verify (loop)" 4 |
1119 | .IP "ev_verify (loop)" 4 |
1077 | .IX Item "ev_loop_verify (loop)" |
1120 | .IX Item "ev_verify (loop)" |
1078 | This function only does something when \f(CW\*(C`EV_VERIFY\*(C'\fR support has been |
1121 | This function only does something when \f(CW\*(C`EV_VERIFY\*(C'\fR support has been |
1079 | compiled in, which is the default for non-minimal builds. It tries to go |
1122 | compiled in, which is the default for non-minimal builds. It tries to go |
1080 | through all internal structures and checks them for validity. If anything |
1123 | through all internal structures and checks them for validity. If anything |
1081 | is found to be inconsistent, it will print an error message to standard |
1124 | is found to be inconsistent, it will print an error message to standard |
1082 | error and call \f(CW\*(C`abort ()\*(C'\fR. |
1125 | error and call \f(CW\*(C`abort ()\*(C'\fR. |
… | |
… | |
1088 | .IX Header "ANATOMY OF A WATCHER" |
1131 | .IX Header "ANATOMY OF A WATCHER" |
1089 | In the following description, uppercase \f(CW\*(C`TYPE\*(C'\fR in names stands for the |
1132 | In the following description, uppercase \f(CW\*(C`TYPE\*(C'\fR in names stands for the |
1090 | watcher type, e.g. \f(CW\*(C`ev_TYPE_start\*(C'\fR can mean \f(CW\*(C`ev_timer_start\*(C'\fR for timer |
1133 | watcher type, e.g. \f(CW\*(C`ev_TYPE_start\*(C'\fR can mean \f(CW\*(C`ev_timer_start\*(C'\fR for timer |
1091 | watchers and \f(CW\*(C`ev_io_start\*(C'\fR for I/O watchers. |
1134 | watchers and \f(CW\*(C`ev_io_start\*(C'\fR for I/O watchers. |
1092 | .PP |
1135 | .PP |
1093 | A watcher is a structure that you create and register to record your |
1136 | A watcher is an opaque structure that you allocate and register to record |
1094 | interest in some event. For instance, if you want to wait for \s-1STDIN\s0 to |
1137 | your interest in some event. To make a concrete example, imagine you want |
1095 | become readable, you would create an \f(CW\*(C`ev_io\*(C'\fR watcher for that: |
1138 | to wait for \s-1STDIN\s0 to become readable, you would create an \f(CW\*(C`ev_io\*(C'\fR watcher |
|
|
1139 | for that: |
1096 | .PP |
1140 | .PP |
1097 | .Vb 5 |
1141 | .Vb 5 |
1098 | \& static void my_cb (struct ev_loop *loop, ev_io *w, int revents) |
1142 | \& static void my_cb (struct ev_loop *loop, ev_io *w, int revents) |
1099 | \& { |
1143 | \& { |
1100 | \& ev_io_stop (w); |
1144 | \& ev_io_stop (w); |
1101 | \& ev_unloop (loop, EVUNLOOP_ALL); |
1145 | \& ev_break (loop, EVBREAK_ALL); |
1102 | \& } |
1146 | \& } |
1103 | \& |
1147 | \& |
1104 | \& struct ev_loop *loop = ev_default_loop (0); |
1148 | \& struct ev_loop *loop = ev_default_loop (0); |
1105 | \& |
1149 | \& |
1106 | \& ev_io stdin_watcher; |
1150 | \& ev_io stdin_watcher; |
1107 | \& |
1151 | \& |
1108 | \& ev_init (&stdin_watcher, my_cb); |
1152 | \& ev_init (&stdin_watcher, my_cb); |
1109 | \& ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ); |
1153 | \& ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ); |
1110 | \& ev_io_start (loop, &stdin_watcher); |
1154 | \& ev_io_start (loop, &stdin_watcher); |
1111 | \& |
1155 | \& |
1112 | \& ev_loop (loop, 0); |
1156 | \& ev_run (loop, 0); |
1113 | .Ve |
1157 | .Ve |
1114 | .PP |
1158 | .PP |
1115 | As you can see, you are responsible for allocating the memory for your |
1159 | As you can see, you are responsible for allocating the memory for your |
1116 | watcher structures (and it is \fIusually\fR a bad idea to do this on the |
1160 | watcher structures (and it is \fIusually\fR a bad idea to do this on the |
1117 | stack). |
1161 | stack). |
1118 | .PP |
1162 | .PP |
1119 | Each watcher has an associated watcher structure (called \f(CW\*(C`struct ev_TYPE\*(C'\fR |
1163 | Each watcher has an associated watcher structure (called \f(CW\*(C`struct ev_TYPE\*(C'\fR |
1120 | or simply \f(CW\*(C`ev_TYPE\*(C'\fR, as typedefs are provided for all watcher structs). |
1164 | or simply \f(CW\*(C`ev_TYPE\*(C'\fR, as typedefs are provided for all watcher structs). |
1121 | .PP |
1165 | .PP |
1122 | Each watcher structure must be initialised by a call to \f(CW\*(C`ev_init |
1166 | Each watcher structure must be initialised by a call to \f(CW\*(C`ev_init (watcher |
1123 | (watcher *, callback)\*(C'\fR, which expects a callback to be provided. This |
1167 | *, callback)\*(C'\fR, which expects a callback to be provided. This callback is |
1124 | callback gets invoked each time the event occurs (or, in the case of I/O |
1168 | invoked each time the event occurs (or, in the case of I/O watchers, each |
1125 | watchers, each time the event loop detects that the file descriptor given |
1169 | time the event loop detects that the file descriptor given is readable |
1126 | is readable and/or writable). |
1170 | and/or writable). |
1127 | .PP |
1171 | .PP |
1128 | Each watcher type further has its own \f(CW\*(C`ev_TYPE_set (watcher *, ...)\*(C'\fR |
1172 | Each watcher type further has its own \f(CW\*(C`ev_TYPE_set (watcher *, ...)\*(C'\fR |
1129 | macro to configure it, with arguments specific to the watcher type. There |
1173 | macro to configure it, with arguments specific to the watcher type. There |
1130 | is also a macro to combine initialisation and setting in one call: \f(CW\*(C`ev_TYPE_init (watcher *, callback, ...)\*(C'\fR. |
1174 | is also a macro to combine initialisation and setting in one call: \f(CW\*(C`ev_TYPE_init (watcher *, callback, ...)\*(C'\fR. |
1131 | .PP |
1175 | .PP |
… | |
… | |
1153 | .el .IP "\f(CWEV_WRITE\fR" 4 |
1197 | .el .IP "\f(CWEV_WRITE\fR" 4 |
1154 | .IX Item "EV_WRITE" |
1198 | .IX Item "EV_WRITE" |
1155 | .PD |
1199 | .PD |
1156 | The file descriptor in the \f(CW\*(C`ev_io\*(C'\fR watcher has become readable and/or |
1200 | The file descriptor in the \f(CW\*(C`ev_io\*(C'\fR watcher has become readable and/or |
1157 | writable. |
1201 | writable. |
1158 | .ie n .IP """EV_TIMEOUT""" 4 |
1202 | .ie n .IP """EV_TIMER""" 4 |
1159 | .el .IP "\f(CWEV_TIMEOUT\fR" 4 |
1203 | .el .IP "\f(CWEV_TIMER\fR" 4 |
1160 | .IX Item "EV_TIMEOUT" |
1204 | .IX Item "EV_TIMER" |
1161 | The \f(CW\*(C`ev_timer\*(C'\fR watcher has timed out. |
1205 | The \f(CW\*(C`ev_timer\*(C'\fR watcher has timed out. |
1162 | .ie n .IP """EV_PERIODIC""" 4 |
1206 | .ie n .IP """EV_PERIODIC""" 4 |
1163 | .el .IP "\f(CWEV_PERIODIC\fR" 4 |
1207 | .el .IP "\f(CWEV_PERIODIC\fR" 4 |
1164 | .IX Item "EV_PERIODIC" |
1208 | .IX Item "EV_PERIODIC" |
1165 | The \f(CW\*(C`ev_periodic\*(C'\fR watcher has timed out. |
1209 | The \f(CW\*(C`ev_periodic\*(C'\fR watcher has timed out. |
… | |
… | |
1185 | .PD 0 |
1229 | .PD 0 |
1186 | .ie n .IP """EV_CHECK""" 4 |
1230 | .ie n .IP """EV_CHECK""" 4 |
1187 | .el .IP "\f(CWEV_CHECK\fR" 4 |
1231 | .el .IP "\f(CWEV_CHECK\fR" 4 |
1188 | .IX Item "EV_CHECK" |
1232 | .IX Item "EV_CHECK" |
1189 | .PD |
1233 | .PD |
1190 | All \f(CW\*(C`ev_prepare\*(C'\fR watchers are invoked just \fIbefore\fR \f(CW\*(C`ev_loop\*(C'\fR starts |
1234 | All \f(CW\*(C`ev_prepare\*(C'\fR watchers are invoked just \fIbefore\fR \f(CW\*(C`ev_run\*(C'\fR starts |
1191 | to gather new events, and all \f(CW\*(C`ev_check\*(C'\fR watchers are invoked just after |
1235 | to gather new events, and all \f(CW\*(C`ev_check\*(C'\fR watchers are invoked just after |
1192 | \&\f(CW\*(C`ev_loop\*(C'\fR has gathered them, but before it invokes any callbacks for any |
1236 | \&\f(CW\*(C`ev_run\*(C'\fR has gathered them, but before it invokes any callbacks for any |
1193 | received events. Callbacks of both watcher types can start and stop as |
1237 | received events. Callbacks of both watcher types can start and stop as |
1194 | many watchers as they want, and all of them will be taken into account |
1238 | many watchers as they want, and all of them will be taken into account |
1195 | (for example, a \f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep |
1239 | (for example, a \f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep |
1196 | \&\f(CW\*(C`ev_loop\*(C'\fR from blocking). |
1240 | \&\f(CW\*(C`ev_run\*(C'\fR from blocking). |
1197 | .ie n .IP """EV_EMBED""" 4 |
1241 | .ie n .IP """EV_EMBED""" 4 |
1198 | .el .IP "\f(CWEV_EMBED\fR" 4 |
1242 | .el .IP "\f(CWEV_EMBED\fR" 4 |
1199 | .IX Item "EV_EMBED" |
1243 | .IX Item "EV_EMBED" |
1200 | The embedded event loop specified in the \f(CW\*(C`ev_embed\*(C'\fR watcher needs attention. |
1244 | The embedded event loop specified in the \f(CW\*(C`ev_embed\*(C'\fR watcher needs attention. |
1201 | .ie n .IP """EV_FORK""" 4 |
1245 | .ie n .IP """EV_FORK""" 4 |
1202 | .el .IP "\f(CWEV_FORK\fR" 4 |
1246 | .el .IP "\f(CWEV_FORK\fR" 4 |
1203 | .IX Item "EV_FORK" |
1247 | .IX Item "EV_FORK" |
1204 | The event loop has been resumed in the child process after fork (see |
1248 | The event loop has been resumed in the child process after fork (see |
1205 | \&\f(CW\*(C`ev_fork\*(C'\fR). |
1249 | \&\f(CW\*(C`ev_fork\*(C'\fR). |
|
|
1250 | .ie n .IP """EV_CLEANUP""" 4 |
|
|
1251 | .el .IP "\f(CWEV_CLEANUP\fR" 4 |
|
|
1252 | .IX Item "EV_CLEANUP" |
|
|
1253 | The event loop is about to be destroyed (see \f(CW\*(C`ev_cleanup\*(C'\fR). |
1206 | .ie n .IP """EV_ASYNC""" 4 |
1254 | .ie n .IP """EV_ASYNC""" 4 |
1207 | .el .IP "\f(CWEV_ASYNC\fR" 4 |
1255 | .el .IP "\f(CWEV_ASYNC\fR" 4 |
1208 | .IX Item "EV_ASYNC" |
1256 | .IX Item "EV_ASYNC" |
1209 | The given async watcher has been asynchronously notified (see \f(CW\*(C`ev_async\*(C'\fR). |
1257 | The given async watcher has been asynchronously notified (see \f(CW\*(C`ev_async\*(C'\fR). |
1210 | .ie n .IP """EV_CUSTOM""" 4 |
1258 | .ie n .IP """EV_CUSTOM""" 4 |
… | |
… | |
1448 | \& { |
1496 | \& { |
1449 | \& struct my_biggy big = (struct my_biggy *) |
1497 | \& struct my_biggy big = (struct my_biggy *) |
1450 | \& (((char *)w) \- offsetof (struct my_biggy, t2)); |
1498 | \& (((char *)w) \- offsetof (struct my_biggy, t2)); |
1451 | \& } |
1499 | \& } |
1452 | .Ve |
1500 | .Ve |
|
|
1501 | .SS "\s-1WATCHER\s0 \s-1STATES\s0" |
|
|
1502 | .IX Subsection "WATCHER STATES" |
|
|
1503 | There are various watcher states mentioned throughout this manual \- |
|
|
1504 | active, pending and so on. In this section these states and the rules to |
|
|
1505 | transition between them will be described in more detail \- and while these |
|
|
1506 | rules might look complicated, they usually do \*(L"the right thing\*(R". |
|
|
1507 | .IP "initialiased" 4 |
|
|
1508 | .IX Item "initialiased" |
|
|
1509 | Before a watcher can be registered with the event looop it has to be |
|
|
1510 | initialised. This can be done with a call to \f(CW\*(C`ev_TYPE_init\*(C'\fR, or calls to |
|
|
1511 | \&\f(CW\*(C`ev_init\*(C'\fR followed by the watcher-specific \f(CW\*(C`ev_TYPE_set\*(C'\fR function. |
|
|
1512 | .Sp |
|
|
1513 | In this state it is simply some block of memory that is suitable for use |
|
|
1514 | in an event loop. It can be moved around, freed, reused etc. at will. |
|
|
1515 | .IP "started/running/active" 4 |
|
|
1516 | .IX Item "started/running/active" |
|
|
1517 | Once a watcher has been started with a call to \f(CW\*(C`ev_TYPE_start\*(C'\fR it becomes |
|
|
1518 | property of the event loop, and is actively waiting for events. While in |
|
|
1519 | this state it cannot be accessed (except in a few documented ways), moved, |
|
|
1520 | freed or anything else \- the only legal thing is to keep a pointer to it, |
|
|
1521 | and call libev functions on it that are documented to work on active watchers. |
|
|
1522 | .IP "pending" 4 |
|
|
1523 | .IX Item "pending" |
|
|
1524 | If a watcher is active and libev determines that an event it is interested |
|
|
1525 | in has occurred (such as a timer expiring), it will become pending. It will |
|
|
1526 | stay in this pending state until either it is stopped or its callback is |
|
|
1527 | about to be invoked, so it is not normally pending inside the watcher |
|
|
1528 | callback. |
|
|
1529 | .Sp |
|
|
1530 | The watcher might or might not be active while it is pending (for example, |
|
|
1531 | an expired non-repeating timer can be pending but no longer active). If it |
|
|
1532 | is stopped, it can be freely accessed (e.g. by calling \f(CW\*(C`ev_TYPE_set\*(C'\fR), |
|
|
1533 | but it is still property of the event loop at this time, so cannot be |
|
|
1534 | moved, freed or reused. And if it is active the rules described in the |
|
|
1535 | previous item still apply. |
|
|
1536 | .Sp |
|
|
1537 | It is also possible to feed an event on a watcher that is not active (e.g. |
|
|
1538 | via \f(CW\*(C`ev_feed_event\*(C'\fR), in which case it becomes pending without being |
|
|
1539 | active. |
|
|
1540 | .IP "stopped" 4 |
|
|
1541 | .IX Item "stopped" |
|
|
1542 | A watcher can be stopped implicitly by libev (in which case it might still |
|
|
1543 | be pending), or explicitly by calling its \f(CW\*(C`ev_TYPE_stop\*(C'\fR function. The |
|
|
1544 | latter will clear any pending state the watcher might be in, regardless |
|
|
1545 | of whether it was active or not, so stopping a watcher explicitly before |
|
|
1546 | freeing it is often a good idea. |
|
|
1547 | .Sp |
|
|
1548 | While stopped (and not pending) the watcher is essentially in the |
|
|
1549 | initialised state, that is it can be reused, moved, modified in any way |
|
|
1550 | you wish. |
1453 | .SS "\s-1WATCHER\s0 \s-1PRIORITY\s0 \s-1MODELS\s0" |
1551 | .SS "\s-1WATCHER\s0 \s-1PRIORITY\s0 \s-1MODELS\s0" |
1454 | .IX Subsection "WATCHER PRIORITY MODELS" |
1552 | .IX Subsection "WATCHER PRIORITY MODELS" |
1455 | Many event loops support \fIwatcher priorities\fR, which are usually small |
1553 | Many event loops support \fIwatcher priorities\fR, which are usually small |
1456 | integers that influence the ordering of event callback invocation |
1554 | integers that influence the ordering of event callback invocation |
1457 | between watchers in some way, all else being equal. |
1555 | between watchers in some way, all else being equal. |
… | |
… | |
1499 | .PP |
1597 | .PP |
1500 | For example, to emulate how many other event libraries handle priorities, |
1598 | For example, to emulate how many other event libraries handle priorities, |
1501 | you can associate an \f(CW\*(C`ev_idle\*(C'\fR watcher to each such watcher, and in |
1599 | you can associate an \f(CW\*(C`ev_idle\*(C'\fR watcher to each such watcher, and in |
1502 | the normal watcher callback, you just start the idle watcher. The real |
1600 | the normal watcher callback, you just start the idle watcher. The real |
1503 | processing is done in the idle watcher callback. This causes libev to |
1601 | processing is done in the idle watcher callback. This causes libev to |
1504 | continously poll and process kernel event data for the watcher, but when |
1602 | continuously poll and process kernel event data for the watcher, but when |
1505 | the lock-out case is known to be rare (which in turn is rare :), this is |
1603 | the lock-out case is known to be rare (which in turn is rare :), this is |
1506 | workable. |
1604 | workable. |
1507 | .PP |
1605 | .PP |
1508 | Usually, however, the lock-out model implemented that way will perform |
1606 | Usually, however, the lock-out model implemented that way will perform |
1509 | miserably under the type of load it was designed to handle. In that case, |
1607 | miserably under the type of load it was designed to handle. In that case, |
… | |
… | |
1524 | \& { |
1622 | \& { |
1525 | \& // stop the I/O watcher, we received the event, but |
1623 | \& // stop the I/O watcher, we received the event, but |
1526 | \& // are not yet ready to handle it. |
1624 | \& // are not yet ready to handle it. |
1527 | \& ev_io_stop (EV_A_ w); |
1625 | \& ev_io_stop (EV_A_ w); |
1528 | \& |
1626 | \& |
1529 | \& // start the idle watcher to ahndle the actual event. |
1627 | \& // start the idle watcher to handle the actual event. |
1530 | \& // it will not be executed as long as other watchers |
1628 | \& // it will not be executed as long as other watchers |
1531 | \& // with the default priority are receiving events. |
1629 | \& // with the default priority are receiving events. |
1532 | \& ev_idle_start (EV_A_ &idle); |
1630 | \& ev_idle_start (EV_A_ &idle); |
1533 | \& } |
1631 | \& } |
1534 | \& |
1632 | \& |
… | |
… | |
1586 | .PP |
1684 | .PP |
1587 | If you cannot use non-blocking mode, then force the use of a |
1685 | If you cannot use non-blocking mode, then force the use of a |
1588 | known-to-be-good backend (at the time of this writing, this includes only |
1686 | known-to-be-good backend (at the time of this writing, this includes only |
1589 | \&\f(CW\*(C`EVBACKEND_SELECT\*(C'\fR and \f(CW\*(C`EVBACKEND_POLL\*(C'\fR). The same applies to file |
1687 | \&\f(CW\*(C`EVBACKEND_SELECT\*(C'\fR and \f(CW\*(C`EVBACKEND_POLL\*(C'\fR). The same applies to file |
1590 | descriptors for which non-blocking operation makes no sense (such as |
1688 | descriptors for which non-blocking operation makes no sense (such as |
1591 | files) \- libev doesn't guarentee any specific behaviour in that case. |
1689 | files) \- libev doesn't guarantee any specific behaviour in that case. |
1592 | .PP |
1690 | .PP |
1593 | Another thing you have to watch out for is that it is quite easy to |
1691 | Another thing you have to watch out for is that it is quite easy to |
1594 | receive \*(L"spurious\*(R" readiness notifications, that is your callback might |
1692 | receive \*(L"spurious\*(R" readiness notifications, that is your callback might |
1595 | be called with \f(CW\*(C`EV_READ\*(C'\fR but a subsequent \f(CW\*(C`read\*(C'\fR(2) will actually block |
1693 | be called with \f(CW\*(C`EV_READ\*(C'\fR but a subsequent \f(CW\*(C`read\*(C'\fR(2) will actually block |
1596 | because there is no data. Not only are some backends known to create a |
1694 | because there is no data. Not only are some backends known to create a |
… | |
… | |
1664 | this is sensible behaviour, for daemons, this is usually undesirable. |
1762 | this is sensible behaviour, for daemons, this is usually undesirable. |
1665 | .PP |
1763 | .PP |
1666 | So when you encounter spurious, unexplained daemon exits, make sure you |
1764 | So when you encounter spurious, unexplained daemon exits, make sure you |
1667 | ignore \s-1SIGPIPE\s0 (and maybe make sure you log the exit status of your daemon |
1765 | ignore \s-1SIGPIPE\s0 (and maybe make sure you log the exit status of your daemon |
1668 | somewhere, as that would have given you a big clue). |
1766 | somewhere, as that would have given you a big clue). |
|
|
1767 | .PP |
|
|
1768 | \fIThe special problem of \fIaccept()\fIing when you can't\fR |
|
|
1769 | .IX Subsection "The special problem of accept()ing when you can't" |
|
|
1770 | .PP |
|
|
1771 | Many implementations of the \s-1POSIX\s0 \f(CW\*(C`accept\*(C'\fR function (for example, |
|
|
1772 | found in post\-2004 Linux) have the peculiar behaviour of not removing a |
|
|
1773 | connection from the pending queue in all error cases. |
|
|
1774 | .PP |
|
|
1775 | For example, larger servers often run out of file descriptors (because |
|
|
1776 | of resource limits), causing \f(CW\*(C`accept\*(C'\fR to fail with \f(CW\*(C`ENFILE\*(C'\fR but not |
|
|
1777 | rejecting the connection, leading to libev signalling readiness on |
|
|
1778 | the next iteration again (the connection still exists after all), and |
|
|
1779 | typically causing the program to loop at 100% \s-1CPU\s0 usage. |
|
|
1780 | .PP |
|
|
1781 | Unfortunately, the set of errors that cause this issue differs between |
|
|
1782 | operating systems, there is usually little the app can do to remedy the |
|
|
1783 | situation, and no known thread-safe method of removing the connection to |
|
|
1784 | cope with overload is known (to me). |
|
|
1785 | .PP |
|
|
1786 | One of the easiest ways to handle this situation is to just ignore it |
|
|
1787 | \&\- when the program encounters an overload, it will just loop until the |
|
|
1788 | situation is over. While this is a form of busy waiting, no \s-1OS\s0 offers an |
|
|
1789 | event-based way to handle this situation, so it's the best one can do. |
|
|
1790 | .PP |
|
|
1791 | A better way to handle the situation is to log any errors other than |
|
|
1792 | \&\f(CW\*(C`EAGAIN\*(C'\fR and \f(CW\*(C`EWOULDBLOCK\*(C'\fR, making sure not to flood the log with such |
|
|
1793 | messages, and continue as usual, which at least gives the user an idea of |
|
|
1794 | what could be wrong (\*(L"raise the ulimit!\*(R"). For extra points one could stop |
|
|
1795 | the \f(CW\*(C`ev_io\*(C'\fR watcher on the listening fd \*(L"for a while\*(R", which reduces \s-1CPU\s0 |
|
|
1796 | usage. |
|
|
1797 | .PP |
|
|
1798 | If your program is single-threaded, then you could also keep a dummy file |
|
|
1799 | descriptor for overload situations (e.g. by opening \fI/dev/null\fR), and |
|
|
1800 | when you run into \f(CW\*(C`ENFILE\*(C'\fR or \f(CW\*(C`EMFILE\*(C'\fR, close it, run \f(CW\*(C`accept\*(C'\fR, |
|
|
1801 | close that fd, and create a new dummy fd. This will gracefully refuse |
|
|
1802 | clients under typical overload conditions. |
|
|
1803 | .PP |
|
|
1804 | The last way to handle it is to simply log the error and \f(CW\*(C`exit\*(C'\fR, as |
|
|
1805 | is often done with \f(CW\*(C`malloc\*(C'\fR failures, but this results in an easy |
|
|
1806 | opportunity for a DoS attack. |
1669 | .PP |
1807 | .PP |
1670 | \fIWatcher-Specific Functions\fR |
1808 | \fIWatcher-Specific Functions\fR |
1671 | .IX Subsection "Watcher-Specific Functions" |
1809 | .IX Subsection "Watcher-Specific Functions" |
1672 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
1810 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
1673 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
1811 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
… | |
… | |
1703 | \& ... |
1841 | \& ... |
1704 | \& struct ev_loop *loop = ev_default_init (0); |
1842 | \& struct ev_loop *loop = ev_default_init (0); |
1705 | \& ev_io stdin_readable; |
1843 | \& ev_io stdin_readable; |
1706 | \& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
1844 | \& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
1707 | \& ev_io_start (loop, &stdin_readable); |
1845 | \& ev_io_start (loop, &stdin_readable); |
1708 | \& ev_loop (loop, 0); |
1846 | \& ev_run (loop, 0); |
1709 | .Ve |
1847 | .Ve |
1710 | .ie n .SS """ev_timer"" \- relative and optionally repeating timeouts" |
1848 | .ie n .SS """ev_timer"" \- relative and optionally repeating timeouts" |
1711 | .el .SS "\f(CWev_timer\fP \- relative and optionally repeating timeouts" |
1849 | .el .SS "\f(CWev_timer\fP \- relative and optionally repeating timeouts" |
1712 | .IX Subsection "ev_timer - relative and optionally repeating timeouts" |
1850 | .IX Subsection "ev_timer - relative and optionally repeating timeouts" |
1713 | Timer watchers are simple relative timers that generate an event after a |
1851 | Timer watchers are simple relative timers that generate an event after a |
… | |
… | |
1722 | The callback is guaranteed to be invoked only \fIafter\fR its timeout has |
1860 | The callback is guaranteed to be invoked only \fIafter\fR its timeout has |
1723 | passed (not \fIat\fR, so on systems with very low-resolution clocks this |
1861 | passed (not \fIat\fR, so on systems with very low-resolution clocks this |
1724 | might introduce a small delay). If multiple timers become ready during the |
1862 | might introduce a small delay). If multiple timers become ready during the |
1725 | same loop iteration then the ones with earlier time-out values are invoked |
1863 | same loop iteration then the ones with earlier time-out values are invoked |
1726 | before ones of the same priority with later time-out values (but this is |
1864 | before ones of the same priority with later time-out values (but this is |
1727 | no longer true when a callback calls \f(CW\*(C`ev_loop\*(C'\fR recursively). |
1865 | no longer true when a callback calls \f(CW\*(C`ev_run\*(C'\fR recursively). |
1728 | .PP |
1866 | .PP |
1729 | \fIBe smart about timeouts\fR |
1867 | \fIBe smart about timeouts\fR |
1730 | .IX Subsection "Be smart about timeouts" |
1868 | .IX Subsection "Be smart about timeouts" |
1731 | .PP |
1869 | .PP |
1732 | Many real-world problems involve some kind of timeout, usually for error |
1870 | Many real-world problems involve some kind of timeout, usually for error |
… | |
… | |
1826 | \& ev_tstamp timeout = last_activity + 60.; |
1964 | \& ev_tstamp timeout = last_activity + 60.; |
1827 | \& |
1965 | \& |
1828 | \& // if last_activity + 60. is older than now, we did time out |
1966 | \& // if last_activity + 60. is older than now, we did time out |
1829 | \& if (timeout < now) |
1967 | \& if (timeout < now) |
1830 | \& { |
1968 | \& { |
1831 | \& // timeout occured, take action |
1969 | \& // timeout occurred, take action |
1832 | \& } |
1970 | \& } |
1833 | \& else |
1971 | \& else |
1834 | \& { |
1972 | \& { |
1835 | \& // callback was invoked, but there was some activity, re\-arm |
1973 | \& // callback was invoked, but there was some activity, re\-arm |
1836 | \& // the watcher to fire in last_activity + 60, which is |
1974 | \& // the watcher to fire in last_activity + 60, which is |
… | |
… | |
1860 | callback, which will \*(L"do the right thing\*(R" and start the timer: |
1998 | callback, which will \*(L"do the right thing\*(R" and start the timer: |
1861 | .Sp |
1999 | .Sp |
1862 | .Vb 3 |
2000 | .Vb 3 |
1863 | \& ev_init (timer, callback); |
2001 | \& ev_init (timer, callback); |
1864 | \& last_activity = ev_now (loop); |
2002 | \& last_activity = ev_now (loop); |
1865 | \& callback (loop, timer, EV_TIMEOUT); |
2003 | \& callback (loop, timer, EV_TIMER); |
1866 | .Ve |
2004 | .Ve |
1867 | .Sp |
2005 | .Sp |
1868 | And when there is some activity, simply store the current time in |
2006 | And when there is some activity, simply store the current time in |
1869 | \&\f(CW\*(C`last_activity\*(C'\fR, no libev calls at all: |
2007 | \&\f(CW\*(C`last_activity\*(C'\fR, no libev calls at all: |
1870 | .Sp |
2008 | .Sp |
1871 | .Vb 1 |
2009 | .Vb 1 |
1872 | \& last_actiivty = ev_now (loop); |
2010 | \& last_activity = ev_now (loop); |
1873 | .Ve |
2011 | .Ve |
1874 | .Sp |
2012 | .Sp |
1875 | This technique is slightly more complex, but in most cases where the |
2013 | This technique is slightly more complex, but in most cases where the |
1876 | time-out is unlikely to be triggered, much more efficient. |
2014 | time-out is unlikely to be triggered, much more efficient. |
1877 | .Sp |
2015 | .Sp |
… | |
… | |
1914 | \fIThe special problem of time updates\fR |
2052 | \fIThe special problem of time updates\fR |
1915 | .IX Subsection "The special problem of time updates" |
2053 | .IX Subsection "The special problem of time updates" |
1916 | .PP |
2054 | .PP |
1917 | Establishing the current time is a costly operation (it usually takes at |
2055 | Establishing the current time is a costly operation (it usually takes at |
1918 | least two system calls): \s-1EV\s0 therefore updates its idea of the current |
2056 | least two system calls): \s-1EV\s0 therefore updates its idea of the current |
1919 | time only before and after \f(CW\*(C`ev_loop\*(C'\fR collects new events, which causes a |
2057 | time only before and after \f(CW\*(C`ev_run\*(C'\fR collects new events, which causes a |
1920 | growing difference between \f(CW\*(C`ev_now ()\*(C'\fR and \f(CW\*(C`ev_time ()\*(C'\fR when handling |
2058 | growing difference between \f(CW\*(C`ev_now ()\*(C'\fR and \f(CW\*(C`ev_time ()\*(C'\fR when handling |
1921 | lots of events in one iteration. |
2059 | lots of events in one iteration. |
1922 | .PP |
2060 | .PP |
1923 | The relative timeouts are calculated relative to the \f(CW\*(C`ev_now ()\*(C'\fR |
2061 | The relative timeouts are calculated relative to the \f(CW\*(C`ev_now ()\*(C'\fR |
1924 | time. This is usually the right thing as this timestamp refers to the time |
2062 | time. This is usually the right thing as this timestamp refers to the time |
… | |
… | |
2003 | Returns the remaining time until a timer fires. If the timer is active, |
2141 | Returns the remaining time until a timer fires. If the timer is active, |
2004 | then this time is relative to the current event loop time, otherwise it's |
2142 | then this time is relative to the current event loop time, otherwise it's |
2005 | the timeout value currently configured. |
2143 | the timeout value currently configured. |
2006 | .Sp |
2144 | .Sp |
2007 | That is, after an \f(CW\*(C`ev_timer_set (w, 5, 7)\*(C'\fR, \f(CW\*(C`ev_timer_remaining\*(C'\fR returns |
2145 | That is, after an \f(CW\*(C`ev_timer_set (w, 5, 7)\*(C'\fR, \f(CW\*(C`ev_timer_remaining\*(C'\fR returns |
2008 | \&\f(CW5\fR. When the timer is started and one second passes, \f(CW\*(C`ev_timer_remain\*(C'\fR |
2146 | \&\f(CW5\fR. When the timer is started and one second passes, \f(CW\*(C`ev_timer_remaining\*(C'\fR |
2009 | will return \f(CW4\fR. When the timer expires and is restarted, it will return |
2147 | will return \f(CW4\fR. When the timer expires and is restarted, it will return |
2010 | roughly \f(CW7\fR (likely slightly less as callback invocation takes some time, |
2148 | roughly \f(CW7\fR (likely slightly less as callback invocation takes some time, |
2011 | too), and so on. |
2149 | too), and so on. |
2012 | .IP "ev_tstamp repeat [read\-write]" 4 |
2150 | .IP "ev_tstamp repeat [read\-write]" 4 |
2013 | .IX Item "ev_tstamp repeat [read-write]" |
2151 | .IX Item "ev_tstamp repeat [read-write]" |
… | |
… | |
2043 | \& } |
2181 | \& } |
2044 | \& |
2182 | \& |
2045 | \& ev_timer mytimer; |
2183 | \& ev_timer mytimer; |
2046 | \& ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */ |
2184 | \& ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */ |
2047 | \& ev_timer_again (&mytimer); /* start timer */ |
2185 | \& ev_timer_again (&mytimer); /* start timer */ |
2048 | \& ev_loop (loop, 0); |
2186 | \& ev_run (loop, 0); |
2049 | \& |
2187 | \& |
2050 | \& // and in some piece of code that gets executed on any "activity": |
2188 | \& // and in some piece of code that gets executed on any "activity": |
2051 | \& // reset the timeout to start ticking again at 10 seconds |
2189 | \& // reset the timeout to start ticking again at 10 seconds |
2052 | \& ev_timer_again (&mytimer); |
2190 | \& ev_timer_again (&mytimer); |
2053 | .Ve |
2191 | .Ve |
… | |
… | |
2079 | .PP |
2217 | .PP |
2080 | As with timers, the callback is guaranteed to be invoked only when the |
2218 | As with timers, the callback is guaranteed to be invoked only when the |
2081 | point in time where it is supposed to trigger has passed. If multiple |
2219 | point in time where it is supposed to trigger has passed. If multiple |
2082 | timers become ready during the same loop iteration then the ones with |
2220 | timers become ready during the same loop iteration then the ones with |
2083 | earlier time-out values are invoked before ones with later time-out values |
2221 | earlier time-out values are invoked before ones with later time-out values |
2084 | (but this is no longer true when a callback calls \f(CW\*(C`ev_loop\*(C'\fR recursively). |
2222 | (but this is no longer true when a callback calls \f(CW\*(C`ev_run\*(C'\fR recursively). |
2085 | .PP |
2223 | .PP |
2086 | \fIWatcher-Specific Functions and Data Members\fR |
2224 | \fIWatcher-Specific Functions and Data Members\fR |
2087 | .IX Subsection "Watcher-Specific Functions and Data Members" |
2225 | .IX Subsection "Watcher-Specific Functions and Data Members" |
2088 | .IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp offset, ev_tstamp interval, reschedule_cb)" 4 |
2226 | .IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp offset, ev_tstamp interval, reschedule_cb)" 4 |
2089 | .IX Item "ev_periodic_init (ev_periodic *, callback, ev_tstamp offset, ev_tstamp interval, reschedule_cb)" |
2227 | .IX Item "ev_periodic_init (ev_periodic *, callback, ev_tstamp offset, ev_tstamp interval, reschedule_cb)" |
… | |
… | |
2216 | system time is divisible by 3600. The callback invocation times have |
2354 | system time is divisible by 3600. The callback invocation times have |
2217 | potentially a lot of jitter, but good long-term stability. |
2355 | potentially a lot of jitter, but good long-term stability. |
2218 | .PP |
2356 | .PP |
2219 | .Vb 5 |
2357 | .Vb 5 |
2220 | \& static void |
2358 | \& static void |
2221 | \& clock_cb (struct ev_loop *loop, ev_io *w, int revents) |
2359 | \& clock_cb (struct ev_loop *loop, ev_periodic *w, int revents) |
2222 | \& { |
2360 | \& { |
2223 | \& ... its now a full hour (UTC, or TAI or whatever your clock follows) |
2361 | \& ... its now a full hour (UTC, or TAI or whatever your clock follows) |
2224 | \& } |
2362 | \& } |
2225 | \& |
2363 | \& |
2226 | \& ev_periodic hourly_tick; |
2364 | \& ev_periodic hourly_tick; |
… | |
… | |
2330 | .PP |
2468 | .PP |
2331 | .Vb 5 |
2469 | .Vb 5 |
2332 | \& static void |
2470 | \& static void |
2333 | \& sigint_cb (struct ev_loop *loop, ev_signal *w, int revents) |
2471 | \& sigint_cb (struct ev_loop *loop, ev_signal *w, int revents) |
2334 | \& { |
2472 | \& { |
2335 | \& ev_unloop (loop, EVUNLOOP_ALL); |
2473 | \& ev_break (loop, EVBREAK_ALL); |
2336 | \& } |
2474 | \& } |
2337 | \& |
2475 | \& |
2338 | \& ev_signal signal_watcher; |
2476 | \& ev_signal signal_watcher; |
2339 | \& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
2477 | \& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
2340 | \& ev_signal_start (loop, &signal_watcher); |
2478 | \& ev_signal_start (loop, &signal_watcher); |
… | |
… | |
2725 | .IX Subsection "ev_prepare and ev_check - customise your event loop!" |
2863 | .IX Subsection "ev_prepare and ev_check - customise your event loop!" |
2726 | Prepare and check watchers are usually (but not always) used in pairs: |
2864 | Prepare and check watchers are usually (but not always) used in pairs: |
2727 | prepare watchers get invoked before the process blocks and check watchers |
2865 | prepare watchers get invoked before the process blocks and check watchers |
2728 | afterwards. |
2866 | afterwards. |
2729 | .PP |
2867 | .PP |
2730 | You \fImust not\fR call \f(CW\*(C`ev_loop\*(C'\fR or similar functions that enter |
2868 | You \fImust not\fR call \f(CW\*(C`ev_run\*(C'\fR or similar functions that enter |
2731 | the current event loop from either \f(CW\*(C`ev_prepare\*(C'\fR or \f(CW\*(C`ev_check\*(C'\fR |
2869 | the current event loop from either \f(CW\*(C`ev_prepare\*(C'\fR or \f(CW\*(C`ev_check\*(C'\fR |
2732 | watchers. Other loops than the current one are fine, however. The |
2870 | watchers. Other loops than the current one are fine, however. The |
2733 | rationale behind this is that you do not need to check for recursion in |
2871 | rationale behind this is that you do not need to check for recursion in |
2734 | those watchers, i.e. the sequence will always be \f(CW\*(C`ev_prepare\*(C'\fR, blocking, |
2872 | those watchers, i.e. the sequence will always be \f(CW\*(C`ev_prepare\*(C'\fR, blocking, |
2735 | \&\f(CW\*(C`ev_check\*(C'\fR so if you have one watcher of each kind they will always be |
2873 | \&\f(CW\*(C`ev_check\*(C'\fR so if you have one watcher of each kind they will always be |
… | |
… | |
2907 | \& |
3045 | \& |
2908 | \& if (timeout >= 0) |
3046 | \& if (timeout >= 0) |
2909 | \& // create/start timer |
3047 | \& // create/start timer |
2910 | \& |
3048 | \& |
2911 | \& // poll |
3049 | \& // poll |
2912 | \& ev_loop (EV_A_ 0); |
3050 | \& ev_run (EV_A_ 0); |
2913 | \& |
3051 | \& |
2914 | \& // stop timer again |
3052 | \& // stop timer again |
2915 | \& if (timeout >= 0) |
3053 | \& if (timeout >= 0) |
2916 | \& ev_timer_stop (EV_A_ &to); |
3054 | \& ev_timer_stop (EV_A_ &to); |
2917 | \& |
3055 | \& |
… | |
… | |
2995 | to invoke it (it will continue to be called until the sweep has been done, |
3133 | to invoke it (it will continue to be called until the sweep has been done, |
2996 | if you do not want that, you need to temporarily stop the embed watcher). |
3134 | if you do not want that, you need to temporarily stop the embed watcher). |
2997 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
3135 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
2998 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
3136 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
2999 | Make a single, non-blocking sweep over the embedded loop. This works |
3137 | Make a single, non-blocking sweep over the embedded loop. This works |
3000 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
3138 | similarly to \f(CW\*(C`ev_run (embedded_loop, EVRUN_NOWAIT)\*(C'\fR, but in the most |
3001 | appropriate way for embedded loops. |
3139 | appropriate way for embedded loops. |
3002 | .IP "struct ev_loop *other [read\-only]" 4 |
3140 | .IP "struct ev_loop *other [read\-only]" 4 |
3003 | .IX Item "struct ev_loop *other [read-only]" |
3141 | .IX Item "struct ev_loop *other [read-only]" |
3004 | The embedded event loop. |
3142 | The embedded event loop. |
3005 | .PP |
3143 | .PP |
… | |
… | |
3067 | handlers will be invoked, too, of course. |
3205 | handlers will be invoked, too, of course. |
3068 | .PP |
3206 | .PP |
3069 | \fIThe special problem of life after fork \- how is it possible?\fR |
3207 | \fIThe special problem of life after fork \- how is it possible?\fR |
3070 | .IX Subsection "The special problem of life after fork - how is it possible?" |
3208 | .IX Subsection "The special problem of life after fork - how is it possible?" |
3071 | .PP |
3209 | .PP |
3072 | Most uses of \f(CW\*(C`fork()\*(C'\fR consist of forking, then some simple calls to ste |
3210 | Most uses of \f(CW\*(C`fork()\*(C'\fR consist of forking, then some simple calls to set |
3073 | up/change the process environment, followed by a call to \f(CW\*(C`exec()\*(C'\fR. This |
3211 | up/change the process environment, followed by a call to \f(CW\*(C`exec()\*(C'\fR. This |
3074 | sequence should be handled by libev without any problems. |
3212 | sequence should be handled by libev without any problems. |
3075 | .PP |
3213 | .PP |
3076 | This changes when the application actually wants to do event handling |
3214 | This changes when the application actually wants to do event handling |
3077 | in the child, or both parent in child, in effect \*(L"continuing\*(R" after the |
3215 | in the child, or both parent in child, in effect \*(L"continuing\*(R" after the |
… | |
… | |
3093 | disadvantage of having to use multiple event loops (which do not support |
3231 | disadvantage of having to use multiple event loops (which do not support |
3094 | signal watchers). |
3232 | signal watchers). |
3095 | .PP |
3233 | .PP |
3096 | When this is not possible, or you want to use the default loop for |
3234 | When this is not possible, or you want to use the default loop for |
3097 | other reasons, then in the process that wants to start \*(L"fresh\*(R", call |
3235 | other reasons, then in the process that wants to start \*(L"fresh\*(R", call |
3098 | \&\f(CW\*(C`ev_default_destroy ()\*(C'\fR followed by \f(CW\*(C`ev_default_loop (...)\*(C'\fR. Destroying |
3236 | \&\f(CW\*(C`ev_loop_destroy (EV_DEFAULT)\*(C'\fR followed by \f(CW\*(C`ev_default_loop (...)\*(C'\fR. |
3099 | the default loop will \*(L"orphan\*(R" (not stop) all registered watchers, so you |
3237 | Destroying the default loop will \*(L"orphan\*(R" (not stop) all registered |
3100 | have to be careful not to execute code that modifies those watchers. Note |
3238 | watchers, so you have to be careful not to execute code that modifies |
3101 | also that in that case, you have to re-register any signal watchers. |
3239 | those watchers. Note also that in that case, you have to re-register any |
|
|
3240 | signal watchers. |
3102 | .PP |
3241 | .PP |
3103 | \fIWatcher-Specific Functions and Data Members\fR |
3242 | \fIWatcher-Specific Functions and Data Members\fR |
3104 | .IX Subsection "Watcher-Specific Functions and Data Members" |
3243 | .IX Subsection "Watcher-Specific Functions and Data Members" |
3105 | .IP "ev_fork_init (ev_signal *, callback)" 4 |
3244 | .IP "ev_fork_init (ev_fork *, callback)" 4 |
3106 | .IX Item "ev_fork_init (ev_signal *, callback)" |
3245 | .IX Item "ev_fork_init (ev_fork *, callback)" |
3107 | Initialises and configures the fork watcher \- it has no parameters of any |
3246 | Initialises and configures the fork watcher \- it has no parameters of any |
3108 | kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless, |
3247 | kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless, |
3109 | believe me. |
3248 | really. |
|
|
3249 | .ie n .SS """ev_cleanup"" \- even the best things end" |
|
|
3250 | .el .SS "\f(CWev_cleanup\fP \- even the best things end" |
|
|
3251 | .IX Subsection "ev_cleanup - even the best things end" |
|
|
3252 | Cleanup watchers are called just before the event loop is being destroyed |
|
|
3253 | by a call to \f(CW\*(C`ev_loop_destroy\*(C'\fR. |
|
|
3254 | .PP |
|
|
3255 | While there is no guarantee that the event loop gets destroyed, cleanup |
|
|
3256 | watchers provide a convenient method to install cleanup hooks for your |
|
|
3257 | program, worker threads and so on \- you just to make sure to destroy the |
|
|
3258 | loop when you want them to be invoked. |
|
|
3259 | .PP |
|
|
3260 | Cleanup watchers are invoked in the same way as any other watcher. Unlike |
|
|
3261 | all other watchers, they do not keep a reference to the event loop (which |
|
|
3262 | makes a lot of sense if you think about it). Like all other watchers, you |
|
|
3263 | can call libev functions in the callback, except \f(CW\*(C`ev_cleanup_start\*(C'\fR. |
|
|
3264 | .PP |
|
|
3265 | \fIWatcher-Specific Functions and Data Members\fR |
|
|
3266 | .IX Subsection "Watcher-Specific Functions and Data Members" |
|
|
3267 | .IP "ev_cleanup_init (ev_cleanup *, callback)" 4 |
|
|
3268 | .IX Item "ev_cleanup_init (ev_cleanup *, callback)" |
|
|
3269 | Initialises and configures the cleanup watcher \- it has no parameters of |
|
|
3270 | any kind. There is a \f(CW\*(C`ev_cleanup_set\*(C'\fR macro, but using it is utterly |
|
|
3271 | pointless, I assure you. |
|
|
3272 | .PP |
|
|
3273 | Example: Register an atexit handler to destroy the default loop, so any |
|
|
3274 | cleanup functions are called. |
|
|
3275 | .PP |
|
|
3276 | .Vb 5 |
|
|
3277 | \& static void |
|
|
3278 | \& program_exits (void) |
|
|
3279 | \& { |
|
|
3280 | \& ev_loop_destroy (EV_DEFAULT_UC); |
|
|
3281 | \& } |
|
|
3282 | \& |
|
|
3283 | \& ... |
|
|
3284 | \& atexit (program_exits); |
|
|
3285 | .Ve |
3110 | .ie n .SS """ev_async"" \- how to wake up another event loop" |
3286 | .ie n .SS """ev_async"" \- how to wake up an event loop" |
3111 | .el .SS "\f(CWev_async\fP \- how to wake up another event loop" |
3287 | .el .SS "\f(CWev_async\fP \- how to wake up an event loop" |
3112 | .IX Subsection "ev_async - how to wake up another event loop" |
3288 | .IX Subsection "ev_async - how to wake up an event loop" |
3113 | In general, you cannot use an \f(CW\*(C`ev_loop\*(C'\fR from multiple threads or other |
3289 | In general, you cannot use an \f(CW\*(C`ev_run\*(C'\fR from multiple threads or other |
3114 | asynchronous sources such as signal handlers (as opposed to multiple event |
3290 | asynchronous sources such as signal handlers (as opposed to multiple event |
3115 | loops \- those are of course safe to use in different threads). |
3291 | loops \- those are of course safe to use in different threads). |
3116 | .PP |
3292 | .PP |
3117 | Sometimes, however, you need to wake up another event loop you do not |
3293 | Sometimes, however, you need to wake up an event loop you do not control, |
3118 | control, for example because it belongs to another thread. This is what |
3294 | for example because it belongs to another thread. This is what \f(CW\*(C`ev_async\*(C'\fR |
3119 | \&\f(CW\*(C`ev_async\*(C'\fR watchers do: as long as the \f(CW\*(C`ev_async\*(C'\fR watcher is active, you |
3295 | watchers do: as long as the \f(CW\*(C`ev_async\*(C'\fR watcher is active, you can signal |
3120 | can signal it by calling \f(CW\*(C`ev_async_send\*(C'\fR, which is thread\- and signal |
3296 | it by calling \f(CW\*(C`ev_async_send\*(C'\fR, which is thread\- and signal safe. |
3121 | safe. |
|
|
3122 | .PP |
3297 | .PP |
3123 | This functionality is very similar to \f(CW\*(C`ev_signal\*(C'\fR watchers, as signals, |
3298 | This functionality is very similar to \f(CW\*(C`ev_signal\*(C'\fR watchers, as signals, |
3124 | too, are asynchronous in nature, and signals, too, will be compressed |
3299 | too, are asynchronous in nature, and signals, too, will be compressed |
3125 | (i.e. the number of callback invocations may be less than the number of |
3300 | (i.e. the number of callback invocations may be less than the number of |
3126 | \&\f(CW\*(C`ev_async_sent\*(C'\fR calls). |
3301 | \&\f(CW\*(C`ev_async_sent\*(C'\fR calls). |
… | |
… | |
3268 | .Sp |
3443 | .Sp |
3269 | If \f(CW\*(C`timeout\*(C'\fR is less than 0, then no timeout watcher will be |
3444 | If \f(CW\*(C`timeout\*(C'\fR is less than 0, then no timeout watcher will be |
3270 | started. Otherwise an \f(CW\*(C`ev_timer\*(C'\fR watcher with after = \f(CW\*(C`timeout\*(C'\fR (and |
3445 | started. Otherwise an \f(CW\*(C`ev_timer\*(C'\fR watcher with after = \f(CW\*(C`timeout\*(C'\fR (and |
3271 | repeat = 0) will be started. \f(CW0\fR is a valid timeout. |
3446 | repeat = 0) will be started. \f(CW0\fR is a valid timeout. |
3272 | .Sp |
3447 | .Sp |
3273 | The callback has the type \f(CW\*(C`void (*cb)(int revents, void *arg)\*(C'\fR and gets |
3448 | The callback has the type \f(CW\*(C`void (*cb)(int revents, void *arg)\*(C'\fR and is |
3274 | passed an \f(CW\*(C`revents\*(C'\fR set like normal event callbacks (a combination of |
3449 | passed an \f(CW\*(C`revents\*(C'\fR set like normal event callbacks (a combination of |
3275 | \&\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 |
3450 | \&\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_TIMER\*(C'\fR) and the \f(CW\*(C`arg\*(C'\fR |
3276 | value passed to \f(CW\*(C`ev_once\*(C'\fR. Note that it is possible to receive \fIboth\fR |
3451 | value passed to \f(CW\*(C`ev_once\*(C'\fR. Note that it is possible to receive \fIboth\fR |
3277 | a timeout and an io event at the same time \- you probably should give io |
3452 | a timeout and an io event at the same time \- you probably should give io |
3278 | events precedence. |
3453 | events precedence. |
3279 | .Sp |
3454 | .Sp |
3280 | Example: wait up to ten seconds for data to appear on \s-1STDIN_FILENO\s0. |
3455 | Example: wait up to ten seconds for data to appear on \s-1STDIN_FILENO\s0. |
… | |
… | |
3282 | .Vb 7 |
3457 | .Vb 7 |
3283 | \& static void stdin_ready (int revents, void *arg) |
3458 | \& static void stdin_ready (int revents, void *arg) |
3284 | \& { |
3459 | \& { |
3285 | \& if (revents & EV_READ) |
3460 | \& if (revents & EV_READ) |
3286 | \& /* stdin might have data for us, joy! */; |
3461 | \& /* stdin might have data for us, joy! */; |
3287 | \& else if (revents & EV_TIMEOUT) |
3462 | \& else if (revents & EV_TIMER) |
3288 | \& /* doh, nothing entered */; |
3463 | \& /* doh, nothing entered */; |
3289 | \& } |
3464 | \& } |
3290 | \& |
3465 | \& |
3291 | \& ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); |
3466 | \& ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0); |
3292 | .Ve |
3467 | .Ve |
… | |
… | |
3417 | \& ev::io iow; |
3592 | \& ev::io iow; |
3418 | \& iow.set <myclass, &myclass::io_cb> (&obj); |
3593 | \& iow.set <myclass, &myclass::io_cb> (&obj); |
3419 | .Ve |
3594 | .Ve |
3420 | .IP "w\->set (object *)" 4 |
3595 | .IP "w\->set (object *)" 4 |
3421 | .IX Item "w->set (object *)" |
3596 | .IX Item "w->set (object *)" |
3422 | This is an \fBexperimental\fR feature that might go away in a future version. |
|
|
3423 | .Sp |
|
|
3424 | This is a variation of a method callback \- leaving out the method to call |
3597 | This is a variation of a method callback \- leaving out the method to call |
3425 | will default the method to \f(CW\*(C`operator ()\*(C'\fR, which makes it possible to use |
3598 | will default the method to \f(CW\*(C`operator ()\*(C'\fR, which makes it possible to use |
3426 | functor objects without having to manually specify the \f(CW\*(C`operator ()\*(C'\fR all |
3599 | functor objects without having to manually specify the \f(CW\*(C`operator ()\*(C'\fR all |
3427 | the time. Incidentally, you can then also leave out the template argument |
3600 | the time. Incidentally, you can then also leave out the template argument |
3428 | list. |
3601 | list. |
… | |
… | |
3468 | .IX Item "w->set (loop)" |
3641 | .IX Item "w->set (loop)" |
3469 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
3642 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
3470 | do this when the watcher is inactive (and not pending either). |
3643 | do this when the watcher is inactive (and not pending either). |
3471 | .IP "w\->set ([arguments])" 4 |
3644 | .IP "w\->set ([arguments])" 4 |
3472 | .IX Item "w->set ([arguments])" |
3645 | .IX Item "w->set ([arguments])" |
3473 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same arguments. Must be |
3646 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same arguments. Either this |
3474 | called at least once. Unlike the C counterpart, an active watcher gets |
3647 | method or a suitable start method must be called at least once. Unlike the |
3475 | automatically stopped and restarted when reconfiguring it with this |
3648 | C counterpart, an active watcher gets automatically stopped and restarted |
3476 | method. |
3649 | when reconfiguring it with this method. |
3477 | .IP "w\->start ()" 4 |
3650 | .IP "w\->start ()" 4 |
3478 | .IX Item "w->start ()" |
3651 | .IX Item "w->start ()" |
3479 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
3652 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
3480 | constructor already stores the event loop. |
3653 | constructor already stores the event loop. |
|
|
3654 | .IP "w\->start ([arguments])" 4 |
|
|
3655 | .IX Item "w->start ([arguments])" |
|
|
3656 | Instead of calling \f(CW\*(C`set\*(C'\fR and \f(CW\*(C`start\*(C'\fR methods separately, it is often |
|
|
3657 | convenient to wrap them in one call. Uses the same type of arguments as |
|
|
3658 | the configure \f(CW\*(C`set\*(C'\fR method of the watcher. |
3481 | .IP "w\->stop ()" 4 |
3659 | .IP "w\->stop ()" 4 |
3482 | .IX Item "w->stop ()" |
3660 | .IX Item "w->stop ()" |
3483 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
3661 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
3484 | .ie n .IP "w\->again () (""ev::timer"", ""ev::periodic"" only)" 4 |
3662 | .ie n .IP "w\->again () (""ev::timer"", ""ev::periodic"" only)" 4 |
3485 | .el .IP "w\->again () (\f(CWev::timer\fR, \f(CWev::periodic\fR only)" 4 |
3663 | .el .IP "w\->again () (\f(CWev::timer\fR, \f(CWev::periodic\fR only)" 4 |
… | |
… | |
3496 | Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR. |
3674 | Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR. |
3497 | .RE |
3675 | .RE |
3498 | .RS 4 |
3676 | .RS 4 |
3499 | .RE |
3677 | .RE |
3500 | .PP |
3678 | .PP |
3501 | Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in |
3679 | Example: Define a class with two I/O and idle watchers, start the I/O |
3502 | the constructor. |
3680 | watchers in the constructor. |
3503 | .PP |
3681 | .PP |
3504 | .Vb 4 |
3682 | .Vb 5 |
3505 | \& class myclass |
3683 | \& class myclass |
3506 | \& { |
3684 | \& { |
3507 | \& ev::io io ; void io_cb (ev::io &w, int revents); |
3685 | \& ev::io io ; void io_cb (ev::io &w, int revents); |
|
|
3686 | \& ev::io2 io2 ; void io2_cb (ev::io &w, int revents); |
3508 | \& ev::idle idle; void idle_cb (ev::idle &w, int revents); |
3687 | \& ev::idle idle; void idle_cb (ev::idle &w, int revents); |
3509 | \& |
3688 | \& |
3510 | \& myclass (int fd) |
3689 | \& myclass (int fd) |
3511 | \& { |
3690 | \& { |
3512 | \& io .set <myclass, &myclass::io_cb > (this); |
3691 | \& io .set <myclass, &myclass::io_cb > (this); |
|
|
3692 | \& io2 .set <myclass, &myclass::io2_cb > (this); |
3513 | \& idle.set <myclass, &myclass::idle_cb> (this); |
3693 | \& idle.set <myclass, &myclass::idle_cb> (this); |
3514 | \& |
3694 | \& |
3515 | \& io.start (fd, ev::READ); |
3695 | \& io.set (fd, ev::WRITE); // configure the watcher |
|
|
3696 | \& io.start (); // start it whenever convenient |
|
|
3697 | \& |
|
|
3698 | \& io2.start (fd, ev::READ); // set + start in one call |
3516 | \& } |
3699 | \& } |
3517 | \& }; |
3700 | \& }; |
3518 | .Ve |
3701 | .Ve |
3519 | .SH "OTHER LANGUAGE BINDINGS" |
3702 | .SH "OTHER LANGUAGE BINDINGS" |
3520 | .IX Header "OTHER LANGUAGE BINDINGS" |
3703 | .IX Header "OTHER LANGUAGE BINDINGS" |
… | |
… | |
3558 | .IX Item "Ocaml" |
3741 | .IX Item "Ocaml" |
3559 | Erkki Seppala has written Ocaml bindings for libev, to be found at |
3742 | Erkki Seppala has written Ocaml bindings for libev, to be found at |
3560 | <http://modeemi.cs.tut.fi/~flux/software/ocaml\-ev/>. |
3743 | <http://modeemi.cs.tut.fi/~flux/software/ocaml\-ev/>. |
3561 | .IP "Lua" 4 |
3744 | .IP "Lua" 4 |
3562 | .IX Item "Lua" |
3745 | .IX Item "Lua" |
3563 | Brian Maher has written a partial interface to libev |
3746 | Brian Maher has written a partial interface to libev for lua (at the |
3564 | for lua (only \f(CW\*(C`ev_io\*(C'\fR and \f(CW\*(C`ev_timer\*(C'\fR), to be found at |
3747 | time of this writing, only \f(CW\*(C`ev_io\*(C'\fR and \f(CW\*(C`ev_timer\*(C'\fR), to be found at |
3565 | <http://github.com/brimworks/lua\-ev>. |
3748 | <http://github.com/brimworks/lua\-ev>. |
3566 | .SH "MACRO MAGIC" |
3749 | .SH "MACRO MAGIC" |
3567 | .IX Header "MACRO MAGIC" |
3750 | .IX Header "MACRO MAGIC" |
3568 | Libev can be compiled with a variety of options, the most fundamental |
3751 | Libev can be compiled with a variety of options, the most fundamental |
3569 | of which is \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) |
3752 | of which is \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) |
… | |
… | |
3579 | \&\f(CW\*(C`EV_A_\*(C'\fR is used when other arguments are following. Example: |
3762 | \&\f(CW\*(C`EV_A_\*(C'\fR is used when other arguments are following. Example: |
3580 | .Sp |
3763 | .Sp |
3581 | .Vb 3 |
3764 | .Vb 3 |
3582 | \& ev_unref (EV_A); |
3765 | \& ev_unref (EV_A); |
3583 | \& ev_timer_add (EV_A_ watcher); |
3766 | \& ev_timer_add (EV_A_ watcher); |
3584 | \& ev_loop (EV_A_ 0); |
3767 | \& ev_run (EV_A_ 0); |
3585 | .Ve |
3768 | .Ve |
3586 | .Sp |
3769 | .Sp |
3587 | It assumes the variable \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR is in scope, |
3770 | It assumes the variable \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR is in scope, |
3588 | which is often provided by the following macro. |
3771 | which is often provided by the following macro. |
3589 | .ie n .IP """EV_P"", ""EV_P_""" 4 |
3772 | .ie n .IP """EV_P"", ""EV_P_""" 4 |
… | |
… | |
3631 | \& } |
3814 | \& } |
3632 | \& |
3815 | \& |
3633 | \& ev_check check; |
3816 | \& ev_check check; |
3634 | \& ev_check_init (&check, check_cb); |
3817 | \& ev_check_init (&check, check_cb); |
3635 | \& ev_check_start (EV_DEFAULT_ &check); |
3818 | \& ev_check_start (EV_DEFAULT_ &check); |
3636 | \& ev_loop (EV_DEFAULT_ 0); |
3819 | \& ev_run (EV_DEFAULT_ 0); |
3637 | .Ve |
3820 | .Ve |
3638 | .SH "EMBEDDING" |
3821 | .SH "EMBEDDING" |
3639 | .IX Header "EMBEDDING" |
3822 | .IX Header "EMBEDDING" |
3640 | Libev can (and often is) directly embedded into host |
3823 | Libev can (and often is) directly embedded into host |
3641 | applications. Examples of applications that embed it include the Deliantra |
3824 | applications. Examples of applications that embed it include the Deliantra |
… | |
… | |
3736 | \& libev.m4 |
3919 | \& libev.m4 |
3737 | .Ve |
3920 | .Ve |
3738 | .SS "\s-1PREPROCESSOR\s0 \s-1SYMBOLS/MACROS\s0" |
3921 | .SS "\s-1PREPROCESSOR\s0 \s-1SYMBOLS/MACROS\s0" |
3739 | .IX Subsection "PREPROCESSOR SYMBOLS/MACROS" |
3922 | .IX Subsection "PREPROCESSOR SYMBOLS/MACROS" |
3740 | Libev can be configured via a variety of preprocessor symbols you have to |
3923 | Libev can be configured via a variety of preprocessor symbols you have to |
3741 | define before including any of its files. The default in the absence of |
3924 | define before including (or compiling) any of its files. The default in |
3742 | autoconf is documented for every option. |
3925 | the absence of autoconf is documented for every option. |
|
|
3926 | .PP |
|
|
3927 | Symbols marked with \*(L"(h)\*(R" do not change the \s-1ABI\s0, and can have different |
|
|
3928 | values when compiling libev vs. including \fIev.h\fR, so it is permissible |
|
|
3929 | to redefine them before including \fIev.h\fR without breaking compatibility |
|
|
3930 | to a compiled library. All other symbols change the \s-1ABI\s0, which means all |
|
|
3931 | users of libev and the libev code itself must be compiled with compatible |
|
|
3932 | settings. |
|
|
3933 | .IP "\s-1EV_COMPAT3\s0 (h)" 4 |
|
|
3934 | .IX Item "EV_COMPAT3 (h)" |
|
|
3935 | Backwards compatibility is a major concern for libev. This is why this |
|
|
3936 | release of libev comes with wrappers for the functions and symbols that |
|
|
3937 | have been renamed between libev version 3 and 4. |
|
|
3938 | .Sp |
|
|
3939 | You can disable these wrappers (to test compatibility with future |
|
|
3940 | versions) by defining \f(CW\*(C`EV_COMPAT3\*(C'\fR to \f(CW0\fR when compiling your |
|
|
3941 | sources. This has the additional advantage that you can drop the \f(CW\*(C`struct\*(C'\fR |
|
|
3942 | from \f(CW\*(C`struct ev_loop\*(C'\fR declarations, as libev will provide an \f(CW\*(C`ev_loop\*(C'\fR |
|
|
3943 | typedef in that case. |
|
|
3944 | .Sp |
|
|
3945 | In some future version, the default for \f(CW\*(C`EV_COMPAT3\*(C'\fR will become \f(CW0\fR, |
|
|
3946 | and in some even more future version the compatibility code will be |
|
|
3947 | removed completely. |
3743 | .IP "\s-1EV_STANDALONE\s0" 4 |
3948 | .IP "\s-1EV_STANDALONE\s0 (h)" 4 |
3744 | .IX Item "EV_STANDALONE" |
3949 | .IX Item "EV_STANDALONE (h)" |
3745 | Must always be \f(CW1\fR if you do not use autoconf configuration, which |
3950 | Must always be \f(CW1\fR if you do not use autoconf configuration, which |
3746 | keeps libev from including \fIconfig.h\fR, and it also defines dummy |
3951 | keeps libev from including \fIconfig.h\fR, and it also defines dummy |
3747 | implementations for some libevent functions (such as logging, which is not |
3952 | implementations for some libevent functions (such as logging, which is not |
3748 | supported). It will also not define any of the structs usually found in |
3953 | supported). It will also not define any of the structs usually found in |
3749 | \&\fIevent.h\fR that are not directly supported by the libev core alone. |
3954 | \&\fIevent.h\fR that are not directly supported by the libev core alone. |
… | |
… | |
3879 | that you know is safe for your purposes. It is used both for signal handler \*(L"locking\*(R" |
4084 | that you know is safe for your purposes. It is used both for signal handler \*(L"locking\*(R" |
3880 | as well as for signal and thread safety in \f(CW\*(C`ev_async\*(C'\fR watchers. |
4085 | as well as for signal and thread safety in \f(CW\*(C`ev_async\*(C'\fR watchers. |
3881 | .Sp |
4086 | .Sp |
3882 | In the absence of this define, libev will use \f(CW\*(C`sig_atomic_t volatile\*(C'\fR |
4087 | In the absence of this define, libev will use \f(CW\*(C`sig_atomic_t volatile\*(C'\fR |
3883 | (from \fIsignal.h\fR), which is usually good enough on most platforms. |
4088 | (from \fIsignal.h\fR), which is usually good enough on most platforms. |
3884 | .IP "\s-1EV_H\s0" 4 |
4089 | .IP "\s-1EV_H\s0 (h)" 4 |
3885 | .IX Item "EV_H" |
4090 | .IX Item "EV_H (h)" |
3886 | The name of the \fIev.h\fR header file used to include it. The default if |
4091 | The name of the \fIev.h\fR header file used to include it. The default if |
3887 | undefined is \f(CW"ev.h"\fR in \fIevent.h\fR, \fIev.c\fR and \fIev++.h\fR. This can be |
4092 | undefined is \f(CW"ev.h"\fR in \fIevent.h\fR, \fIev.c\fR and \fIev++.h\fR. This can be |
3888 | used to virtually rename the \fIev.h\fR header file in case of conflicts. |
4093 | used to virtually rename the \fIev.h\fR header file in case of conflicts. |
3889 | .IP "\s-1EV_CONFIG_H\s0" 4 |
4094 | .IP "\s-1EV_CONFIG_H\s0 (h)" 4 |
3890 | .IX Item "EV_CONFIG_H" |
4095 | .IX Item "EV_CONFIG_H (h)" |
3891 | If \f(CW\*(C`EV_STANDALONE\*(C'\fR isn't \f(CW1\fR, this variable can be used to override |
4096 | If \f(CW\*(C`EV_STANDALONE\*(C'\fR isn't \f(CW1\fR, this variable can be used to override |
3892 | \&\fIev.c\fR's idea of where to find the \fIconfig.h\fR file, similarly to |
4097 | \&\fIev.c\fR's idea of where to find the \fIconfig.h\fR file, similarly to |
3893 | \&\f(CW\*(C`EV_H\*(C'\fR, above. |
4098 | \&\f(CW\*(C`EV_H\*(C'\fR, above. |
3894 | .IP "\s-1EV_EVENT_H\s0" 4 |
4099 | .IP "\s-1EV_EVENT_H\s0 (h)" 4 |
3895 | .IX Item "EV_EVENT_H" |
4100 | .IX Item "EV_EVENT_H (h)" |
3896 | Similarly to \f(CW\*(C`EV_H\*(C'\fR, this macro can be used to override \fIevent.c\fR's idea |
4101 | Similarly to \f(CW\*(C`EV_H\*(C'\fR, this macro can be used to override \fIevent.c\fR's idea |
3897 | of how the \fIevent.h\fR header can be found, the default is \f(CW"event.h"\fR. |
4102 | of how the \fIevent.h\fR header can be found, the default is \f(CW"event.h"\fR. |
3898 | .IP "\s-1EV_PROTOTYPES\s0" 4 |
4103 | .IP "\s-1EV_PROTOTYPES\s0 (h)" 4 |
3899 | .IX Item "EV_PROTOTYPES" |
4104 | .IX Item "EV_PROTOTYPES (h)" |
3900 | If defined to be \f(CW0\fR, then \fIev.h\fR will not define any function |
4105 | If defined to be \f(CW0\fR, then \fIev.h\fR will not define any function |
3901 | prototypes, but still define all the structs and other symbols. This is |
4106 | prototypes, but still define all the structs and other symbols. This is |
3902 | occasionally useful if you want to provide your own wrapper functions |
4107 | occasionally useful if you want to provide your own wrapper functions |
3903 | around libev functions. |
4108 | around libev functions. |
3904 | .IP "\s-1EV_MULTIPLICITY\s0" 4 |
4109 | .IP "\s-1EV_MULTIPLICITY\s0" 4 |
… | |
… | |
3924 | and time, so using the defaults of five priorities (\-2 .. +2) is usually |
4129 | and time, so using the defaults of five priorities (\-2 .. +2) is usually |
3925 | fine. |
4130 | fine. |
3926 | .Sp |
4131 | .Sp |
3927 | If your embedding application does not need any priorities, defining these |
4132 | If your embedding application does not need any priorities, defining these |
3928 | both to \f(CW0\fR will save some memory and \s-1CPU\s0. |
4133 | both to \f(CW0\fR will save some memory and \s-1CPU\s0. |
3929 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
4134 | .IP "\s-1EV_PERIODIC_ENABLE\s0, \s-1EV_IDLE_ENABLE\s0, \s-1EV_EMBED_ENABLE\s0, \s-1EV_STAT_ENABLE\s0, \s-1EV_PREPARE_ENABLE\s0, \s-1EV_CHECK_ENABLE\s0, \s-1EV_FORK_ENABLE\s0, \s-1EV_SIGNAL_ENABLE\s0, \s-1EV_ASYNC_ENABLE\s0, \s-1EV_CHILD_ENABLE\s0." 4 |
3930 | .IX Item "EV_PERIODIC_ENABLE" |
4135 | .IX Item "EV_PERIODIC_ENABLE, EV_IDLE_ENABLE, EV_EMBED_ENABLE, EV_STAT_ENABLE, EV_PREPARE_ENABLE, EV_CHECK_ENABLE, EV_FORK_ENABLE, EV_SIGNAL_ENABLE, EV_ASYNC_ENABLE, EV_CHILD_ENABLE." |
3931 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
4136 | If undefined or defined to be \f(CW1\fR (and the platform supports it), then |
3932 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
4137 | the respective watcher type is supported. If defined to be \f(CW0\fR, then it |
3933 | code. |
4138 | is not. Disabling watcher types mainly saves code size. |
3934 | .IP "\s-1EV_IDLE_ENABLE\s0" 4 |
|
|
3935 | .IX Item "EV_IDLE_ENABLE" |
|
|
3936 | If undefined or defined to be \f(CW1\fR, then idle watchers are supported. If |
|
|
3937 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
|
|
3938 | code. |
|
|
3939 | .IP "\s-1EV_EMBED_ENABLE\s0" 4 |
|
|
3940 | .IX Item "EV_EMBED_ENABLE" |
|
|
3941 | If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If |
|
|
3942 | defined to be \f(CW0\fR, then they are not. Embed watchers rely on most other |
|
|
3943 | watcher types, which therefore must not be disabled. |
|
|
3944 | .IP "\s-1EV_STAT_ENABLE\s0" 4 |
4139 | .IP "\s-1EV_FEATURES\s0" 4 |
3945 | .IX Item "EV_STAT_ENABLE" |
4140 | .IX Item "EV_FEATURES" |
3946 | If undefined or defined to be \f(CW1\fR, then stat watchers are supported. If |
|
|
3947 | defined to be \f(CW0\fR, then they are not. |
|
|
3948 | .IP "\s-1EV_FORK_ENABLE\s0" 4 |
|
|
3949 | .IX Item "EV_FORK_ENABLE" |
|
|
3950 | If undefined or defined to be \f(CW1\fR, then fork watchers are supported. If |
|
|
3951 | defined to be \f(CW0\fR, then they are not. |
|
|
3952 | .IP "\s-1EV_ASYNC_ENABLE\s0" 4 |
|
|
3953 | .IX Item "EV_ASYNC_ENABLE" |
|
|
3954 | If undefined or defined to be \f(CW1\fR, then async watchers are supported. If |
|
|
3955 | defined to be \f(CW0\fR, then they are not. |
|
|
3956 | .IP "\s-1EV_MINIMAL\s0" 4 |
|
|
3957 | .IX Item "EV_MINIMAL" |
|
|
3958 | If you need to shave off some kilobytes of code at the expense of some |
4141 | If you need to shave off some kilobytes of code at the expense of some |
3959 | speed (but with the full \s-1API\s0), define this symbol to \f(CW1\fR. Currently this |
4142 | speed (but with the full \s-1API\s0), you can define this symbol to request |
3960 | is used to override some inlining decisions, saves roughly 30% code size |
4143 | certain subsets of functionality. The default is to enable all features |
3961 | on amd64. It also selects a much smaller 2\-heap for timer management over |
4144 | that can be enabled on the platform. |
3962 | the default 4\-heap. |
|
|
3963 | .Sp |
4145 | .Sp |
3964 | You can save even more by disabling watcher types you do not need |
4146 | A typical way to use this symbol is to define it to \f(CW0\fR (or to a bitset |
3965 | and setting \f(CW\*(C`EV_MAXPRI\*(C'\fR == \f(CW\*(C`EV_MINPRI\*(C'\fR. Also, disabling \f(CW\*(C`assert\*(C'\fR |
4147 | with some broad features you want) and then selectively re-enable |
3966 | (\f(CW\*(C`\-DNDEBUG\*(C'\fR) will usually reduce code size a lot. |
4148 | additional parts you want, for example if you want everything minimal, |
|
|
4149 | but multiple event loop support, async and child watchers and the poll |
|
|
4150 | backend, use this: |
3967 | .Sp |
4151 | .Sp |
3968 | Defining \f(CW\*(C`EV_MINIMAL\*(C'\fR to \f(CW2\fR will additionally reduce the core \s-1API\s0 to |
4152 | .Vb 5 |
3969 | provide a bare-bones event library. See \f(CW\*(C`ev.h\*(C'\fR for details on what parts |
4153 | \& #define EV_FEATURES 0 |
3970 | of the \s-1API\s0 are still available, and do not complain if this subset changes |
4154 | \& #define EV_MULTIPLICITY 1 |
3971 | over time. |
4155 | \& #define EV_USE_POLL 1 |
|
|
4156 | \& #define EV_CHILD_ENABLE 1 |
|
|
4157 | \& #define EV_ASYNC_ENABLE 1 |
|
|
4158 | .Ve |
|
|
4159 | .Sp |
|
|
4160 | The actual value is a bitset, it can be a combination of the following |
|
|
4161 | values: |
|
|
4162 | .RS 4 |
|
|
4163 | .ie n .IP "1 \- faster/larger code" 4 |
|
|
4164 | .el .IP "\f(CW1\fR \- faster/larger code" 4 |
|
|
4165 | .IX Item "1 - faster/larger code" |
|
|
4166 | Use larger code to speed up some operations. |
|
|
4167 | .Sp |
|
|
4168 | Currently this is used to override some inlining decisions (enlarging the |
|
|
4169 | code size by roughly 30% on amd64). |
|
|
4170 | .Sp |
|
|
4171 | When optimising for size, use of compiler flags such as \f(CW\*(C`\-Os\*(C'\fR with |
|
|
4172 | gcc is recommended, as well as \f(CW\*(C`\-DNDEBUG\*(C'\fR, as libev contains a number of |
|
|
4173 | assertions. |
|
|
4174 | .ie n .IP "2 \- faster/larger data structures" 4 |
|
|
4175 | .el .IP "\f(CW2\fR \- faster/larger data structures" 4 |
|
|
4176 | .IX Item "2 - faster/larger data structures" |
|
|
4177 | Replaces the small 2\-heap for timer management by a faster 4\-heap, larger |
|
|
4178 | hash table sizes and so on. This will usually further increase code size |
|
|
4179 | and can additionally have an effect on the size of data structures at |
|
|
4180 | runtime. |
|
|
4181 | .ie n .IP "4 \- full \s-1API\s0 configuration" 4 |
|
|
4182 | .el .IP "\f(CW4\fR \- full \s-1API\s0 configuration" 4 |
|
|
4183 | .IX Item "4 - full API configuration" |
|
|
4184 | This enables priorities (sets \f(CW\*(C`EV_MAXPRI\*(C'\fR=2 and \f(CW\*(C`EV_MINPRI\*(C'\fR=\-2), and |
|
|
4185 | enables multiplicity (\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR=1). |
|
|
4186 | .ie n .IP "8 \- full \s-1API\s0" 4 |
|
|
4187 | .el .IP "\f(CW8\fR \- full \s-1API\s0" 4 |
|
|
4188 | .IX Item "8 - full API" |
|
|
4189 | This enables a lot of the \*(L"lesser used\*(R" \s-1API\s0 functions. See \f(CW\*(C`ev.h\*(C'\fR for |
|
|
4190 | details on which parts of the \s-1API\s0 are still available without this |
|
|
4191 | feature, and do not complain if this subset changes over time. |
|
|
4192 | .ie n .IP "16 \- enable all optional watcher types" 4 |
|
|
4193 | .el .IP "\f(CW16\fR \- enable all optional watcher types" 4 |
|
|
4194 | .IX Item "16 - enable all optional watcher types" |
|
|
4195 | Enables all optional watcher types. If you want to selectively enable |
|
|
4196 | only some watcher types other than I/O and timers (e.g. prepare, |
|
|
4197 | embed, async, child...) you can enable them manually by defining |
|
|
4198 | \&\f(CW\*(C`EV_watchertype_ENABLE\*(C'\fR to \f(CW1\fR instead. |
|
|
4199 | .ie n .IP "32 \- enable all backends" 4 |
|
|
4200 | .el .IP "\f(CW32\fR \- enable all backends" 4 |
|
|
4201 | .IX Item "32 - enable all backends" |
|
|
4202 | This enables all backends \- without this feature, you need to enable at |
|
|
4203 | least one backend manually (\f(CW\*(C`EV_USE_SELECT\*(C'\fR is a good choice). |
|
|
4204 | .ie n .IP "64 \- enable OS-specific ""helper"" APIs" 4 |
|
|
4205 | .el .IP "\f(CW64\fR \- enable OS-specific ``helper'' APIs" 4 |
|
|
4206 | .IX Item "64 - enable OS-specific helper APIs" |
|
|
4207 | Enable inotify, eventfd, signalfd and similar OS-specific helper APIs by |
|
|
4208 | default. |
|
|
4209 | .RE |
|
|
4210 | .RS 4 |
|
|
4211 | .Sp |
|
|
4212 | Compiling with \f(CW\*(C`gcc \-Os \-DEV_STANDALONE \-DEV_USE_EPOLL=1 \-DEV_FEATURES=0\*(C'\fR |
|
|
4213 | reduces the compiled size of libev from 24.7Kb code/2.8Kb data to 6.5Kb |
|
|
4214 | code/0.3Kb data on my GNU/Linux amd64 system, while still giving you I/O |
|
|
4215 | watchers, timers and monotonic clock support. |
|
|
4216 | .Sp |
|
|
4217 | With an intelligent-enough linker (gcc+binutils are intelligent enough |
|
|
4218 | when you use \f(CW\*(C`\-Wl,\-\-gc\-sections \-ffunction\-sections\*(C'\fR) functions unused by |
|
|
4219 | your program might be left out as well \- a binary starting a timer and an |
|
|
4220 | I/O watcher then might come out at only 5Kb. |
|
|
4221 | .RE |
|
|
4222 | .IP "\s-1EV_AVOID_STDIO\s0" 4 |
|
|
4223 | .IX Item "EV_AVOID_STDIO" |
|
|
4224 | If this is set to \f(CW1\fR at compiletime, then libev will avoid using stdio |
|
|
4225 | functions (printf, scanf, perror etc.). This will increase the code size |
|
|
4226 | somewhat, but if your program doesn't otherwise depend on stdio and your |
|
|
4227 | libc allows it, this avoids linking in the stdio library which is quite |
|
|
4228 | big. |
|
|
4229 | .Sp |
|
|
4230 | Note that error messages might become less precise when this option is |
|
|
4231 | enabled. |
3972 | .IP "\s-1EV_NSIG\s0" 4 |
4232 | .IP "\s-1EV_NSIG\s0" 4 |
3973 | .IX Item "EV_NSIG" |
4233 | .IX Item "EV_NSIG" |
3974 | The highest supported signal number, +1 (or, the number of |
4234 | The highest supported signal number, +1 (or, the number of |
3975 | signals): Normally, libev tries to deduce the maximum number of signals |
4235 | signals): Normally, libev tries to deduce the maximum number of signals |
3976 | automatically, but sometimes this fails, in which case it can be |
4236 | automatically, but sometimes this fails, in which case it can be |
3977 | specified. Also, using a lower number than detected (\f(CW32\fR should be |
4237 | specified. Also, using a lower number than detected (\f(CW32\fR should be |
3978 | good for about any system in existance) can save some memory, as libev |
4238 | good for about any system in existence) can save some memory, as libev |
3979 | statically allocates some 12\-24 bytes per signal number. |
4239 | statically allocates some 12\-24 bytes per signal number. |
3980 | .IP "\s-1EV_PID_HASHSIZE\s0" 4 |
4240 | .IP "\s-1EV_PID_HASHSIZE\s0" 4 |
3981 | .IX Item "EV_PID_HASHSIZE" |
4241 | .IX Item "EV_PID_HASHSIZE" |
3982 | \&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by |
4242 | \&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by |
3983 | pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more |
4243 | pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_FEATURES\*(C'\fR disabled), |
3984 | than enough. If you need to manage thousands of children you might want to |
4244 | usually more than enough. If you need to manage thousands of children you |
3985 | increase this value (\fImust\fR be a power of two). |
4245 | might want to increase this value (\fImust\fR be a power of two). |
3986 | .IP "\s-1EV_INOTIFY_HASHSIZE\s0" 4 |
4246 | .IP "\s-1EV_INOTIFY_HASHSIZE\s0" 4 |
3987 | .IX Item "EV_INOTIFY_HASHSIZE" |
4247 | .IX Item "EV_INOTIFY_HASHSIZE" |
3988 | \&\f(CW\*(C`ev_stat\*(C'\fR watchers use a small hash table to distribute workload by |
4248 | \&\f(CW\*(C`ev_stat\*(C'\fR watchers use a small hash table to distribute workload by |
3989 | inotify watch id. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), |
4249 | inotify watch id. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_FEATURES\*(C'\fR |
3990 | usually more than enough. If you need to manage thousands of \f(CW\*(C`ev_stat\*(C'\fR |
4250 | disabled), usually more than enough. If you need to manage thousands of |
3991 | watchers you might want to increase this value (\fImust\fR be a power of |
4251 | \&\f(CW\*(C`ev_stat\*(C'\fR watchers you might want to increase this value (\fImust\fR be a |
3992 | two). |
4252 | power of two). |
3993 | .IP "\s-1EV_USE_4HEAP\s0" 4 |
4253 | .IP "\s-1EV_USE_4HEAP\s0" 4 |
3994 | .IX Item "EV_USE_4HEAP" |
4254 | .IX Item "EV_USE_4HEAP" |
3995 | Heaps are not very cache-efficient. To improve the cache-efficiency of the |
4255 | Heaps are not very cache-efficient. To improve the cache-efficiency of the |
3996 | timer and periodics heaps, libev uses a 4\-heap when this symbol is defined |
4256 | timer and periodics heaps, libev uses a 4\-heap when this symbol is defined |
3997 | to \f(CW1\fR. The 4\-heap uses more complicated (longer) code but has noticeably |
4257 | to \f(CW1\fR. The 4\-heap uses more complicated (longer) code but has noticeably |
3998 | faster performance with many (thousands) of watchers. |
4258 | faster performance with many (thousands) of watchers. |
3999 | .Sp |
4259 | .Sp |
4000 | The default is \f(CW1\fR unless \f(CW\*(C`EV_MINIMAL\*(C'\fR is set in which case it is \f(CW0\fR |
4260 | The default is \f(CW1\fR, unless \f(CW\*(C`EV_FEATURES\*(C'\fR overrides it, in which case it |
4001 | (disabled). |
4261 | will be \f(CW0\fR. |
4002 | .IP "\s-1EV_HEAP_CACHE_AT\s0" 4 |
4262 | .IP "\s-1EV_HEAP_CACHE_AT\s0" 4 |
4003 | .IX Item "EV_HEAP_CACHE_AT" |
4263 | .IX Item "EV_HEAP_CACHE_AT" |
4004 | Heaps are not very cache-efficient. To improve the cache-efficiency of the |
4264 | Heaps are not very cache-efficient. To improve the cache-efficiency of the |
4005 | timer and periodics heaps, libev can cache the timestamp (\fIat\fR) within |
4265 | timer and periodics heaps, libev can cache the timestamp (\fIat\fR) within |
4006 | the heap structure (selected by defining \f(CW\*(C`EV_HEAP_CACHE_AT\*(C'\fR to \f(CW1\fR), |
4266 | the heap structure (selected by defining \f(CW\*(C`EV_HEAP_CACHE_AT\*(C'\fR to \f(CW1\fR), |
4007 | which uses 8\-12 bytes more per watcher and a few hundred bytes more code, |
4267 | which uses 8\-12 bytes more per watcher and a few hundred bytes more code, |
4008 | but avoids random read accesses on heap changes. This improves performance |
4268 | but avoids random read accesses on heap changes. This improves performance |
4009 | noticeably with many (hundreds) of watchers. |
4269 | noticeably with many (hundreds) of watchers. |
4010 | .Sp |
4270 | .Sp |
4011 | The default is \f(CW1\fR unless \f(CW\*(C`EV_MINIMAL\*(C'\fR is set in which case it is \f(CW0\fR |
4271 | The default is \f(CW1\fR, unless \f(CW\*(C`EV_FEATURES\*(C'\fR overrides it, in which case it |
4012 | (disabled). |
4272 | will be \f(CW0\fR. |
4013 | .IP "\s-1EV_VERIFY\s0" 4 |
4273 | .IP "\s-1EV_VERIFY\s0" 4 |
4014 | .IX Item "EV_VERIFY" |
4274 | .IX Item "EV_VERIFY" |
4015 | Controls how much internal verification (see \f(CW\*(C`ev_loop_verify ()\*(C'\fR) will |
4275 | Controls how much internal verification (see \f(CW\*(C`ev_verify ()\*(C'\fR) will |
4016 | be done: If set to \f(CW0\fR, no internal verification code will be compiled |
4276 | be done: If set to \f(CW0\fR, no internal verification code will be compiled |
4017 | in. If set to \f(CW1\fR, then verification code will be compiled in, but not |
4277 | in. If set to \f(CW1\fR, then verification code will be compiled in, but not |
4018 | called. If set to \f(CW2\fR, then the internal verification code will be |
4278 | called. If set to \f(CW2\fR, then the internal verification code will be |
4019 | called once per loop, which can slow down libev. If set to \f(CW3\fR, then the |
4279 | called once per loop, which can slow down libev. If set to \f(CW3\fR, then the |
4020 | verification code will be called very frequently, which will slow down |
4280 | verification code will be called very frequently, which will slow down |
4021 | libev considerably. |
4281 | libev considerably. |
4022 | .Sp |
4282 | .Sp |
4023 | The default is \f(CW1\fR, unless \f(CW\*(C`EV_MINIMAL\*(C'\fR is set, in which case it will be |
4283 | The default is \f(CW1\fR, unless \f(CW\*(C`EV_FEATURES\*(C'\fR overrides it, in which case it |
4024 | \&\f(CW0\fR. |
4284 | will be \f(CW0\fR. |
4025 | .IP "\s-1EV_COMMON\s0" 4 |
4285 | .IP "\s-1EV_COMMON\s0" 4 |
4026 | .IX Item "EV_COMMON" |
4286 | .IX Item "EV_COMMON" |
4027 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
4287 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
4028 | this macro to a something else you can include more and other types of |
4288 | this macro to something else you can include more and other types of |
4029 | members. You have to define it each time you include one of the files, |
4289 | members. You have to define it each time you include one of the files, |
4030 | though, and it must be identical each time. |
4290 | though, and it must be identical each time. |
4031 | .Sp |
4291 | .Sp |
4032 | For example, the perl \s-1EV\s0 module uses something like this: |
4292 | For example, the perl \s-1EV\s0 module uses something like this: |
4033 | .Sp |
4293 | .Sp |
… | |
… | |
4091 | file. |
4351 | file. |
4092 | .PP |
4352 | .PP |
4093 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
4353 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
4094 | that everybody includes and which overrides some configure choices: |
4354 | that everybody includes and which overrides some configure choices: |
4095 | .PP |
4355 | .PP |
4096 | .Vb 9 |
4356 | .Vb 8 |
4097 | \& #define EV_MINIMAL 1 |
4357 | \& #define EV_FEATURES 8 |
4098 | \& #define EV_USE_POLL 0 |
4358 | \& #define EV_USE_SELECT 1 |
4099 | \& #define EV_MULTIPLICITY 0 |
|
|
4100 | \& #define EV_PERIODIC_ENABLE 0 |
4359 | \& #define EV_PREPARE_ENABLE 1 |
|
|
4360 | \& #define EV_IDLE_ENABLE 1 |
4101 | \& #define EV_STAT_ENABLE 0 |
4361 | \& #define EV_SIGNAL_ENABLE 1 |
4102 | \& #define EV_FORK_ENABLE 0 |
4362 | \& #define EV_CHILD_ENABLE 1 |
|
|
4363 | \& #define EV_USE_STDEXCEPT 0 |
4103 | \& #define EV_CONFIG_H <config.h> |
4364 | \& #define EV_CONFIG_H <config.h> |
4104 | \& #define EV_MINPRI 0 |
|
|
4105 | \& #define EV_MAXPRI 0 |
|
|
4106 | \& |
4365 | \& |
4107 | \& #include "ev++.h" |
4366 | \& #include "ev++.h" |
4108 | .Ve |
4367 | .Ve |
4109 | .PP |
4368 | .PP |
4110 | And a \fIev_cpp.C\fR implementation file that contains libev proper and is compiled: |
4369 | And a \fIev_cpp.C\fR implementation file that contains libev proper and is compiled: |
… | |
… | |
4247 | \& pthread_mutex_lock (&u\->lock); |
4506 | \& pthread_mutex_lock (&u\->lock); |
4248 | \& } |
4507 | \& } |
4249 | .Ve |
4508 | .Ve |
4250 | .PP |
4509 | .PP |
4251 | The event loop thread first acquires the mutex, and then jumps straight |
4510 | The event loop thread first acquires the mutex, and then jumps straight |
4252 | into \f(CW\*(C`ev_loop\*(C'\fR: |
4511 | into \f(CW\*(C`ev_run\*(C'\fR: |
4253 | .PP |
4512 | .PP |
4254 | .Vb 4 |
4513 | .Vb 4 |
4255 | \& void * |
4514 | \& void * |
4256 | \& l_run (void *thr_arg) |
4515 | \& l_run (void *thr_arg) |
4257 | \& { |
4516 | \& { |
4258 | \& struct ev_loop *loop = (struct ev_loop *)thr_arg; |
4517 | \& struct ev_loop *loop = (struct ev_loop *)thr_arg; |
4259 | \& |
4518 | \& |
4260 | \& l_acquire (EV_A); |
4519 | \& l_acquire (EV_A); |
4261 | \& pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0); |
4520 | \& pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0); |
4262 | \& ev_loop (EV_A_ 0); |
4521 | \& ev_run (EV_A_ 0); |
4263 | \& l_release (EV_A); |
4522 | \& l_release (EV_A); |
4264 | \& |
4523 | \& |
4265 | \& return 0; |
4524 | \& return 0; |
4266 | \& } |
4525 | \& } |
4267 | .Ve |
4526 | .Ve |
… | |
… | |
4327 | \fI\s-1COROUTINES\s0\fR |
4586 | \fI\s-1COROUTINES\s0\fR |
4328 | .IX Subsection "COROUTINES" |
4587 | .IX Subsection "COROUTINES" |
4329 | .PP |
4588 | .PP |
4330 | Libev is very accommodating to coroutines (\*(L"cooperative threads\*(R"): |
4589 | Libev is very accommodating to coroutines (\*(L"cooperative threads\*(R"): |
4331 | libev fully supports nesting calls to its functions from different |
4590 | libev fully supports nesting calls to its functions from different |
4332 | coroutines (e.g. you can call \f(CW\*(C`ev_loop\*(C'\fR on the same loop from two |
4591 | coroutines (e.g. you can call \f(CW\*(C`ev_run\*(C'\fR on the same loop from two |
4333 | different coroutines, and switch freely between both coroutines running |
4592 | different coroutines, and switch freely between both coroutines running |
4334 | the loop, as long as you don't confuse yourself). The only exception is |
4593 | the loop, as long as you don't confuse yourself). The only exception is |
4335 | that you must not do this from \f(CW\*(C`ev_periodic\*(C'\fR reschedule callbacks. |
4594 | that you must not do this from \f(CW\*(C`ev_periodic\*(C'\fR reschedule callbacks. |
4336 | .PP |
4595 | .PP |
4337 | Care has been taken to ensure that libev does not keep local state inside |
4596 | Care has been taken to ensure that libev does not keep local state inside |
4338 | \&\f(CW\*(C`ev_loop\*(C'\fR, and other calls do not usually allow for coroutine switches as |
4597 | \&\f(CW\*(C`ev_run\*(C'\fR, and other calls do not usually allow for coroutine switches as |
4339 | they do not call any callbacks. |
4598 | they do not call any callbacks. |
4340 | .SS "\s-1COMPILER\s0 \s-1WARNINGS\s0" |
4599 | .SS "\s-1COMPILER\s0 \s-1WARNINGS\s0" |
4341 | .IX Subsection "COMPILER WARNINGS" |
4600 | .IX Subsection "COMPILER WARNINGS" |
4342 | Depending on your compiler and compiler settings, you might get no or a |
4601 | Depending on your compiler and compiler settings, you might get no or a |
4343 | lot of warnings when compiling libev code. Some people are apparently |
4602 | lot of warnings when compiling libev code. Some people are apparently |
… | |
… | |
4353 | maintainable. |
4612 | maintainable. |
4354 | .PP |
4613 | .PP |
4355 | And of course, some compiler warnings are just plain stupid, or simply |
4614 | And of course, some compiler warnings are just plain stupid, or simply |
4356 | wrong (because they don't actually warn about the condition their message |
4615 | wrong (because they don't actually warn about the condition their message |
4357 | seems to warn about). For example, certain older gcc versions had some |
4616 | seems to warn about). For example, certain older gcc versions had some |
4358 | warnings that resulted an extreme number of false positives. These have |
4617 | warnings that resulted in an extreme number of false positives. These have |
4359 | been fixed, but some people still insist on making code warn-free with |
4618 | been fixed, but some people still insist on making code warn-free with |
4360 | such buggy versions. |
4619 | such buggy versions. |
4361 | .PP |
4620 | .PP |
4362 | While libev is written to generate as few warnings as possible, |
4621 | While libev is written to generate as few warnings as possible, |
4363 | \&\*(L"warn-free\*(R" code is not a goal, and it is recommended not to build libev |
4622 | \&\*(L"warn-free\*(R" code is not a goal, and it is recommended not to build libev |
… | |
… | |
4397 | .PP |
4656 | .PP |
4398 | If you need, for some reason, empty reports from valgrind for your project |
4657 | If you need, for some reason, empty reports from valgrind for your project |
4399 | I suggest using suppression lists. |
4658 | I suggest using suppression lists. |
4400 | .SH "PORTABILITY NOTES" |
4659 | .SH "PORTABILITY NOTES" |
4401 | .IX Header "PORTABILITY NOTES" |
4660 | .IX Header "PORTABILITY NOTES" |
|
|
4661 | .SS "\s-1GNU/LINUX\s0 32 \s-1BIT\s0 \s-1LIMITATIONS\s0" |
|
|
4662 | .IX Subsection "GNU/LINUX 32 BIT LIMITATIONS" |
|
|
4663 | GNU/Linux is the only common platform that supports 64 bit file/large file |
|
|
4664 | interfaces but \fIdisables\fR them by default. |
|
|
4665 | .PP |
|
|
4666 | That means that libev compiled in the default environment doesn't support |
|
|
4667 | files larger than 2GiB or so, which mainly affects \f(CW\*(C`ev_stat\*(C'\fR watchers. |
|
|
4668 | .PP |
|
|
4669 | Unfortunately, many programs try to work around this GNU/Linux issue |
|
|
4670 | by enabling the large file \s-1API\s0, which makes them incompatible with the |
|
|
4671 | standard libev compiled for their system. |
|
|
4672 | .PP |
|
|
4673 | Likewise, libev cannot enable the large file \s-1API\s0 itself as this would |
|
|
4674 | suddenly make it incompatible to the default compile time environment, |
|
|
4675 | i.e. all programs not using special compile switches. |
|
|
4676 | .SS "\s-1OS/X\s0 \s-1AND\s0 \s-1DARWIN\s0 \s-1BUGS\s0" |
|
|
4677 | .IX Subsection "OS/X AND DARWIN BUGS" |
|
|
4678 | The whole thing is a bug if you ask me \- basically any system interface |
|
|
4679 | you touch is broken, whether it is locales, poll, kqueue or even the |
|
|
4680 | OpenGL drivers. |
|
|
4681 | .PP |
|
|
4682 | \fI\f(CI\*(C`kqueue\*(C'\fI is buggy\fR |
|
|
4683 | .IX Subsection "kqueue is buggy" |
|
|
4684 | .PP |
|
|
4685 | The kqueue syscall is broken in all known versions \- most versions support |
|
|
4686 | only sockets, many support pipes. |
|
|
4687 | .PP |
|
|
4688 | Libev tries to work around this by not using \f(CW\*(C`kqueue\*(C'\fR by default on this |
|
|
4689 | rotten platform, but of course you can still ask for it when creating a |
|
|
4690 | loop \- embedding a socket-only kqueue loop into a select-based one is |
|
|
4691 | probably going to work well. |
|
|
4692 | .PP |
|
|
4693 | \fI\f(CI\*(C`poll\*(C'\fI is buggy\fR |
|
|
4694 | .IX Subsection "poll is buggy" |
|
|
4695 | .PP |
|
|
4696 | Instead of fixing \f(CW\*(C`kqueue\*(C'\fR, Apple replaced their (working) \f(CW\*(C`poll\*(C'\fR |
|
|
4697 | implementation by something calling \f(CW\*(C`kqueue\*(C'\fR internally around the 10.5.6 |
|
|
4698 | release, so now \f(CW\*(C`kqueue\*(C'\fR \fIand\fR \f(CW\*(C`poll\*(C'\fR are broken. |
|
|
4699 | .PP |
|
|
4700 | Libev tries to work around this by not using \f(CW\*(C`poll\*(C'\fR by default on |
|
|
4701 | this rotten platform, but of course you can still ask for it when creating |
|
|
4702 | a loop. |
|
|
4703 | .PP |
|
|
4704 | \fI\f(CI\*(C`select\*(C'\fI is buggy\fR |
|
|
4705 | .IX Subsection "select is buggy" |
|
|
4706 | .PP |
|
|
4707 | All that's left is \f(CW\*(C`select\*(C'\fR, and of course Apple found a way to fuck this |
|
|
4708 | one up as well: On \s-1OS/X\s0, \f(CW\*(C`select\*(C'\fR actively limits the number of file |
|
|
4709 | descriptors you can pass in to 1024 \- your program suddenly crashes when |
|
|
4710 | you use more. |
|
|
4711 | .PP |
|
|
4712 | There is an undocumented \*(L"workaround\*(R" for this \- defining |
|
|
4713 | \&\f(CW\*(C`_DARWIN_UNLIMITED_SELECT\*(C'\fR, which libev tries to use, so select \fIshould\fR |
|
|
4714 | work on \s-1OS/X\s0. |
|
|
4715 | .SS "\s-1SOLARIS\s0 \s-1PROBLEMS\s0 \s-1AND\s0 \s-1WORKAROUNDS\s0" |
|
|
4716 | .IX Subsection "SOLARIS PROBLEMS AND WORKAROUNDS" |
|
|
4717 | \fI\f(CI\*(C`errno\*(C'\fI reentrancy\fR |
|
|
4718 | .IX Subsection "errno reentrancy" |
|
|
4719 | .PP |
|
|
4720 | The default compile environment on Solaris is unfortunately so |
|
|
4721 | thread-unsafe that you can't even use components/libraries compiled |
|
|
4722 | without \f(CW\*(C`\-D_REENTRANT\*(C'\fR in a threaded program, which, of course, isn't |
|
|
4723 | defined by default. A valid, if stupid, implementation choice. |
|
|
4724 | .PP |
|
|
4725 | If you want to use libev in threaded environments you have to make sure |
|
|
4726 | it's compiled with \f(CW\*(C`_REENTRANT\*(C'\fR defined. |
|
|
4727 | .PP |
|
|
4728 | \fIEvent port backend\fR |
|
|
4729 | .IX Subsection "Event port backend" |
|
|
4730 | .PP |
|
|
4731 | The scalable event interface for Solaris is called \*(L"event |
|
|
4732 | ports\*(R". Unfortunately, this mechanism is very buggy in all major |
|
|
4733 | releases. If you run into high \s-1CPU\s0 usage, your program freezes or you get |
|
|
4734 | a large number of spurious wakeups, make sure you have all the relevant |
|
|
4735 | and latest kernel patches applied. No, I don't know which ones, but there |
|
|
4736 | are multiple ones to apply, and afterwards, event ports actually work |
|
|
4737 | great. |
|
|
4738 | .PP |
|
|
4739 | If you can't get it to work, you can try running the program by setting |
|
|
4740 | the environment variable \f(CW\*(C`LIBEV_FLAGS=3\*(C'\fR to only allow \f(CW\*(C`poll\*(C'\fR and |
|
|
4741 | \&\f(CW\*(C`select\*(C'\fR backends. |
|
|
4742 | .SS "\s-1AIX\s0 \s-1POLL\s0 \s-1BUG\s0" |
|
|
4743 | .IX Subsection "AIX POLL BUG" |
|
|
4744 | \&\s-1AIX\s0 unfortunately has a broken \f(CW\*(C`poll.h\*(C'\fR header. Libev works around |
|
|
4745 | this by trying to avoid the poll backend altogether (i.e. it's not even |
|
|
4746 | compiled in), which normally isn't a big problem as \f(CW\*(C`select\*(C'\fR works fine |
|
|
4747 | with large bitsets on \s-1AIX\s0, and \s-1AIX\s0 is dead anyway. |
4402 | .SS "\s-1WIN32\s0 \s-1PLATFORM\s0 \s-1LIMITATIONS\s0 \s-1AND\s0 \s-1WORKAROUNDS\s0" |
4748 | .SS "\s-1WIN32\s0 \s-1PLATFORM\s0 \s-1LIMITATIONS\s0 \s-1AND\s0 \s-1WORKAROUNDS\s0" |
4403 | .IX Subsection "WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS" |
4749 | .IX Subsection "WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS" |
|
|
4750 | \fIGeneral issues\fR |
|
|
4751 | .IX Subsection "General issues" |
|
|
4752 | .PP |
4404 | Win32 doesn't support any of the standards (e.g. \s-1POSIX\s0) that libev |
4753 | Win32 doesn't support any of the standards (e.g. \s-1POSIX\s0) that libev |
4405 | requires, and its I/O model is fundamentally incompatible with the \s-1POSIX\s0 |
4754 | requires, and its I/O model is fundamentally incompatible with the \s-1POSIX\s0 |
4406 | model. Libev still offers limited functionality on this platform in |
4755 | model. Libev still offers limited functionality on this platform in |
4407 | the form of the \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR backend, and only supports socket |
4756 | the form of the \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR backend, and only supports socket |
4408 | descriptors. This only applies when using Win32 natively, not when using |
4757 | descriptors. This only applies when using Win32 natively, not when using |
4409 | e.g. cygwin. |
4758 | e.g. cygwin. Actually, it only applies to the microsofts own compilers, |
|
|
4759 | as every compielr comes with a slightly differently broken/incompatible |
|
|
4760 | environment. |
4410 | .PP |
4761 | .PP |
4411 | Lifting these limitations would basically require the full |
4762 | Lifting these limitations would basically require the full |
4412 | re-implementation of the I/O system. If you are into these kinds of |
4763 | re-implementation of the I/O system. If you are into this kind of thing, |
4413 | things, then note that glib does exactly that for you in a very portable |
4764 | then note that glib does exactly that for you in a very portable way (note |
4414 | way (note also that glib is the slowest event library known to man). |
4765 | also that glib is the slowest event library known to man). |
4415 | .PP |
4766 | .PP |
4416 | There is no supported compilation method available on windows except |
4767 | There is no supported compilation method available on windows except |
4417 | embedding it into other applications. |
4768 | embedding it into other applications. |
4418 | .PP |
4769 | .PP |
4419 | Sensible signal handling is officially unsupported by Microsoft \- libev |
4770 | Sensible signal handling is officially unsupported by Microsoft \- libev |
… | |
… | |
4450 | .PP |
4801 | .PP |
4451 | .Vb 2 |
4802 | .Vb 2 |
4452 | \& #include "evwrap.h" |
4803 | \& #include "evwrap.h" |
4453 | \& #include "ev.c" |
4804 | \& #include "ev.c" |
4454 | .Ve |
4805 | .Ve |
4455 | .IP "The winsocket select function" 4 |
4806 | .PP |
|
|
4807 | \fIThe winsocket \f(CI\*(C`select\*(C'\fI function\fR |
4456 | .IX Item "The winsocket select function" |
4808 | .IX Subsection "The winsocket select function" |
|
|
4809 | .PP |
4457 | The winsocket \f(CW\*(C`select\*(C'\fR function doesn't follow \s-1POSIX\s0 in that it |
4810 | The winsocket \f(CW\*(C`select\*(C'\fR function doesn't follow \s-1POSIX\s0 in that it |
4458 | requires socket \fIhandles\fR and not socket \fIfile descriptors\fR (it is |
4811 | requires socket \fIhandles\fR and not socket \fIfile descriptors\fR (it is |
4459 | also extremely buggy). This makes select very inefficient, and also |
4812 | also extremely buggy). This makes select very inefficient, and also |
4460 | requires a mapping from file descriptors to socket handles (the Microsoft |
4813 | requires a mapping from file descriptors to socket handles (the Microsoft |
4461 | C runtime provides the function \f(CW\*(C`_open_osfhandle\*(C'\fR for this). See the |
4814 | C runtime provides the function \f(CW\*(C`_open_osfhandle\*(C'\fR for this). See the |
4462 | discussion of the \f(CW\*(C`EV_SELECT_USE_FD_SET\*(C'\fR, \f(CW\*(C`EV_SELECT_IS_WINSOCKET\*(C'\fR and |
4815 | discussion of the \f(CW\*(C`EV_SELECT_USE_FD_SET\*(C'\fR, \f(CW\*(C`EV_SELECT_IS_WINSOCKET\*(C'\fR and |
4463 | \&\f(CW\*(C`EV_FD_TO_WIN32_HANDLE\*(C'\fR preprocessor symbols for more info. |
4816 | \&\f(CW\*(C`EV_FD_TO_WIN32_HANDLE\*(C'\fR preprocessor symbols for more info. |
4464 | .Sp |
4817 | .PP |
4465 | The configuration for a \*(L"naked\*(R" win32 using the Microsoft runtime |
4818 | The configuration for a \*(L"naked\*(R" win32 using the Microsoft runtime |
4466 | libraries and raw winsocket select is: |
4819 | libraries and raw winsocket select is: |
4467 | .Sp |
4820 | .PP |
4468 | .Vb 2 |
4821 | .Vb 2 |
4469 | \& #define EV_USE_SELECT 1 |
4822 | \& #define EV_USE_SELECT 1 |
4470 | \& #define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */ |
4823 | \& #define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */ |
4471 | .Ve |
4824 | .Ve |
4472 | .Sp |
4825 | .PP |
4473 | Note that winsockets handling of fd sets is O(n), so you can easily get a |
4826 | Note that winsockets handling of fd sets is O(n), so you can easily get a |
4474 | complexity in the O(nA\*^X) range when using win32. |
4827 | complexity in the O(nA\*^X) range when using win32. |
|
|
4828 | .PP |
4475 | .IP "Limited number of file descriptors" 4 |
4829 | \fILimited number of file descriptors\fR |
4476 | .IX Item "Limited number of file descriptors" |
4830 | .IX Subsection "Limited number of file descriptors" |
|
|
4831 | .PP |
4477 | Windows has numerous arbitrary (and low) limits on things. |
4832 | Windows has numerous arbitrary (and low) limits on things. |
4478 | .Sp |
4833 | .PP |
4479 | Early versions of winsocket's select only supported waiting for a maximum |
4834 | Early versions of winsocket's select only supported waiting for a maximum |
4480 | of \f(CW64\fR handles (probably owning to the fact that all windows kernels |
4835 | of \f(CW64\fR handles (probably owning to the fact that all windows kernels |
4481 | can only wait for \f(CW64\fR things at the same time internally; Microsoft |
4836 | can only wait for \f(CW64\fR things at the same time internally; Microsoft |
4482 | recommends spawning a chain of threads and wait for 63 handles and the |
4837 | recommends spawning a chain of threads and wait for 63 handles and the |
4483 | previous thread in each. Sounds great!). |
4838 | previous thread in each. Sounds great!). |
4484 | .Sp |
4839 | .PP |
4485 | Newer versions support more handles, but you need to define \f(CW\*(C`FD_SETSIZE\*(C'\fR |
4840 | Newer versions support more handles, but you need to define \f(CW\*(C`FD_SETSIZE\*(C'\fR |
4486 | to some high number (e.g. \f(CW2048\fR) before compiling the winsocket select |
4841 | to some high number (e.g. \f(CW2048\fR) before compiling the winsocket select |
4487 | call (which might be in libev or elsewhere, for example, perl and many |
4842 | call (which might be in libev or elsewhere, for example, perl and many |
4488 | other interpreters do their own select emulation on windows). |
4843 | other interpreters do their own select emulation on windows). |
4489 | .Sp |
4844 | .PP |
4490 | Another limit is the number of file descriptors in the Microsoft runtime |
4845 | Another limit is the number of file descriptors in the Microsoft runtime |
4491 | libraries, which by default is \f(CW64\fR (there must be a hidden \fI64\fR |
4846 | libraries, which by default is \f(CW64\fR (there must be a hidden \fI64\fR |
4492 | fetish or something like this inside Microsoft). You can increase this |
4847 | fetish or something like this inside Microsoft). You can increase this |
4493 | by calling \f(CW\*(C`_setmaxstdio\*(C'\fR, which can increase this limit to \f(CW2048\fR |
4848 | by calling \f(CW\*(C`_setmaxstdio\*(C'\fR, which can increase this limit to \f(CW2048\fR |
4494 | (another arbitrary limit), but is broken in many versions of the Microsoft |
4849 | (another arbitrary limit), but is broken in many versions of the Microsoft |
… | |
… | |
4506 | Libev assumes not only that all watcher pointers have the same internal |
4861 | Libev assumes not only that all watcher pointers have the same internal |
4507 | structure (guaranteed by \s-1POSIX\s0 but not by \s-1ISO\s0 C for example), but it also |
4862 | structure (guaranteed by \s-1POSIX\s0 but not by \s-1ISO\s0 C for example), but it also |
4508 | assumes that the same (machine) code can be used to call any watcher |
4863 | assumes that the same (machine) code can be used to call any watcher |
4509 | callback: The watcher callbacks have different type signatures, but libev |
4864 | callback: The watcher callbacks have different type signatures, but libev |
4510 | calls them using an \f(CW\*(C`ev_watcher *\*(C'\fR internally. |
4865 | calls them using an \f(CW\*(C`ev_watcher *\*(C'\fR internally. |
|
|
4866 | .IP "pointer accesses must be thread-atomic" 4 |
|
|
4867 | .IX Item "pointer accesses must be thread-atomic" |
|
|
4868 | Accessing a pointer value must be atomic, it must both be readable and |
|
|
4869 | writable in one piece \- this is the case on all current architectures. |
4511 | .ie n .IP """sig_atomic_t volatile"" must be thread-atomic as well" 4 |
4870 | .ie n .IP """sig_atomic_t volatile"" must be thread-atomic as well" 4 |
4512 | .el .IP "\f(CWsig_atomic_t volatile\fR must be thread-atomic as well" 4 |
4871 | .el .IP "\f(CWsig_atomic_t volatile\fR must be thread-atomic as well" 4 |
4513 | .IX Item "sig_atomic_t volatile must be thread-atomic as well" |
4872 | .IX Item "sig_atomic_t volatile must be thread-atomic as well" |
4514 | The type \f(CW\*(C`sig_atomic_t volatile\*(C'\fR (or whatever is defined as |
4873 | The type \f(CW\*(C`sig_atomic_t volatile\*(C'\fR (or whatever is defined as |
4515 | \&\f(CW\*(C`EV_ATOMIC_T\*(C'\fR) must be atomic with respect to accesses from different |
4874 | \&\f(CW\*(C`EV_ATOMIC_T\*(C'\fR) must be atomic with respect to accesses from different |
… | |
… | |
4538 | watchers. |
4897 | watchers. |
4539 | .ie n .IP """double"" must hold a time value in seconds with enough accuracy" 4 |
4898 | .ie n .IP """double"" must hold a time value in seconds with enough accuracy" 4 |
4540 | .el .IP "\f(CWdouble\fR must hold a time value in seconds with enough accuracy" 4 |
4899 | .el .IP "\f(CWdouble\fR must hold a time value in seconds with enough accuracy" 4 |
4541 | .IX Item "double must hold a time value in seconds with enough accuracy" |
4900 | .IX Item "double must hold a time value in seconds with enough accuracy" |
4542 | The type \f(CW\*(C`double\*(C'\fR is used to represent timestamps. It is required to |
4901 | The type \f(CW\*(C`double\*(C'\fR is used to represent timestamps. It is required to |
4543 | have at least 51 bits of mantissa (and 9 bits of exponent), which is good |
4902 | have at least 51 bits of mantissa (and 9 bits of exponent), which is |
4544 | enough for at least into the year 4000. This requirement is fulfilled by |
4903 | good enough for at least into the year 4000 with millisecond accuracy |
|
|
4904 | (the design goal for libev). This requirement is overfulfilled by |
4545 | implementations implementing \s-1IEEE\s0 754, which is basically all existing |
4905 | implementations using \s-1IEEE\s0 754, which is basically all existing ones. With |
4546 | ones. With \s-1IEEE\s0 754 doubles, you get microsecond accuracy until at least |
4906 | \&\s-1IEEE\s0 754 doubles, you get microsecond accuracy until at least 2200. |
4547 | 2200. |
|
|
4548 | .PP |
4907 | .PP |
4549 | If you know of other additional requirements drop me a note. |
4908 | If you know of other additional requirements drop me a note. |
4550 | .SH "ALGORITHMIC COMPLEXITIES" |
4909 | .SH "ALGORITHMIC COMPLEXITIES" |
4551 | .IX Header "ALGORITHMIC COMPLEXITIES" |
4910 | .IX Header "ALGORITHMIC COMPLEXITIES" |
4552 | In this section the complexities of (many of) the algorithms used inside |
4911 | In this section the complexities of (many of) the algorithms used inside |
… | |
… | |
4608 | .IX Item "Processing signals: O(max_signal_number)" |
4967 | .IX Item "Processing signals: O(max_signal_number)" |
4609 | .PD |
4968 | .PD |
4610 | Sending involves a system call \fIiff\fR there were no other \f(CW\*(C`ev_async_send\*(C'\fR |
4969 | Sending involves a system call \fIiff\fR there were no other \f(CW\*(C`ev_async_send\*(C'\fR |
4611 | calls in the current loop iteration. Checking for async and signal events |
4970 | calls in the current loop iteration. Checking for async and signal events |
4612 | involves iterating over all running async watchers or all signal numbers. |
4971 | involves iterating over all running async watchers or all signal numbers. |
|
|
4972 | .SH "PORTING FROM LIBEV 3.X TO 4.X" |
|
|
4973 | .IX Header "PORTING FROM LIBEV 3.X TO 4.X" |
|
|
4974 | The major version 4 introduced some incompatible changes to the \s-1API\s0. |
|
|
4975 | .PP |
|
|
4976 | At the moment, the \f(CW\*(C`ev.h\*(C'\fR header file provides compatibility definitions |
|
|
4977 | for all changes, so most programs should still compile. The compatibility |
|
|
4978 | layer might be removed in later versions of libev, so better update to the |
|
|
4979 | new \s-1API\s0 early than late. |
|
|
4980 | .ie n .IP """EV_COMPAT3"" backwards compatibility mechanism" 4 |
|
|
4981 | .el .IP "\f(CWEV_COMPAT3\fR backwards compatibility mechanism" 4 |
|
|
4982 | .IX Item "EV_COMPAT3 backwards compatibility mechanism" |
|
|
4983 | The backward compatibility mechanism can be controlled by |
|
|
4984 | \&\f(CW\*(C`EV_COMPAT3\*(C'\fR. See \*(L"\s-1MACROS\s0\*(R" in \s-1PREPROCESSOR\s0 \s-1SYMBOLS\s0 in the \s-1EMBEDDING\s0 |
|
|
4985 | section. |
|
|
4986 | .ie n .IP """ev_default_destroy"" and ""ev_default_fork"" have been removed" 4 |
|
|
4987 | .el .IP "\f(CWev_default_destroy\fR and \f(CWev_default_fork\fR have been removed" 4 |
|
|
4988 | .IX Item "ev_default_destroy and ev_default_fork have been removed" |
|
|
4989 | These calls can be replaced easily by their \f(CW\*(C`ev_loop_xxx\*(C'\fR counterparts: |
|
|
4990 | .Sp |
|
|
4991 | .Vb 2 |
|
|
4992 | \& ev_loop_destroy (EV_DEFAULT_UC); |
|
|
4993 | \& ev_loop_fork (EV_DEFAULT); |
|
|
4994 | .Ve |
|
|
4995 | .IP "function/symbol renames" 4 |
|
|
4996 | .IX Item "function/symbol renames" |
|
|
4997 | A number of functions and symbols have been renamed: |
|
|
4998 | .Sp |
|
|
4999 | .Vb 3 |
|
|
5000 | \& ev_loop => ev_run |
|
|
5001 | \& EVLOOP_NONBLOCK => EVRUN_NOWAIT |
|
|
5002 | \& EVLOOP_ONESHOT => EVRUN_ONCE |
|
|
5003 | \& |
|
|
5004 | \& ev_unloop => ev_break |
|
|
5005 | \& EVUNLOOP_CANCEL => EVBREAK_CANCEL |
|
|
5006 | \& EVUNLOOP_ONE => EVBREAK_ONE |
|
|
5007 | \& EVUNLOOP_ALL => EVBREAK_ALL |
|
|
5008 | \& |
|
|
5009 | \& EV_TIMEOUT => EV_TIMER |
|
|
5010 | \& |
|
|
5011 | \& ev_loop_count => ev_iteration |
|
|
5012 | \& ev_loop_depth => ev_depth |
|
|
5013 | \& ev_loop_verify => ev_verify |
|
|
5014 | .Ve |
|
|
5015 | .Sp |
|
|
5016 | Most functions working on \f(CW\*(C`struct ev_loop\*(C'\fR objects don't have an |
|
|
5017 | \&\f(CW\*(C`ev_loop_\*(C'\fR prefix, so it was removed; \f(CW\*(C`ev_loop\*(C'\fR, \f(CW\*(C`ev_unloop\*(C'\fR and |
|
|
5018 | associated constants have been renamed to not collide with the \f(CW\*(C`struct |
|
|
5019 | ev_loop\*(C'\fR anymore and \f(CW\*(C`EV_TIMER\*(C'\fR now follows the same naming scheme |
|
|
5020 | as all other watcher types. Note that \f(CW\*(C`ev_loop_fork\*(C'\fR is still called |
|
|
5021 | \&\f(CW\*(C`ev_loop_fork\*(C'\fR because it would otherwise clash with the \f(CW\*(C`ev_fork\*(C'\fR |
|
|
5022 | typedef. |
|
|
5023 | .ie n .IP """EV_MINIMAL"" mechanism replaced by ""EV_FEATURES""" 4 |
|
|
5024 | .el .IP "\f(CWEV_MINIMAL\fR mechanism replaced by \f(CWEV_FEATURES\fR" 4 |
|
|
5025 | .IX Item "EV_MINIMAL mechanism replaced by EV_FEATURES" |
|
|
5026 | The preprocessor symbol \f(CW\*(C`EV_MINIMAL\*(C'\fR has been replaced by a different |
|
|
5027 | mechanism, \f(CW\*(C`EV_FEATURES\*(C'\fR. Programs using \f(CW\*(C`EV_MINIMAL\*(C'\fR usually compile |
|
|
5028 | and work, but the library code will of course be larger. |
4613 | .SH "GLOSSARY" |
5029 | .SH "GLOSSARY" |
4614 | .IX Header "GLOSSARY" |
5030 | .IX Header "GLOSSARY" |
4615 | .IP "active" 4 |
5031 | .IP "active" 4 |
4616 | .IX Item "active" |
5032 | .IX Item "active" |
4617 | A watcher is active as long as it has been started (has been attached to |
5033 | A watcher is active as long as it has been started and not yet stopped. |
4618 | an event loop) but not yet stopped (disassociated from the event loop). |
5034 | See \*(L"\s-1WATCHER\s0 \s-1STATES\s0\*(R" for details. |
4619 | .IP "application" 4 |
5035 | .IP "application" 4 |
4620 | .IX Item "application" |
5036 | .IX Item "application" |
4621 | In this document, an application is whatever is using libev. |
5037 | In this document, an application is whatever is using libev. |
|
|
5038 | .IP "backend" 4 |
|
|
5039 | .IX Item "backend" |
|
|
5040 | The part of the code dealing with the operating system interfaces. |
4622 | .IP "callback" 4 |
5041 | .IP "callback" 4 |
4623 | .IX Item "callback" |
5042 | .IX Item "callback" |
4624 | The address of a function that is called when some event has been |
5043 | The address of a function that is called when some event has been |
4625 | detected. Callbacks are being passed the event loop, the watcher that |
5044 | detected. Callbacks are being passed the event loop, the watcher that |
4626 | received the event, and the actual event bitset. |
5045 | received the event, and the actual event bitset. |
4627 | .IP "callback invocation" 4 |
5046 | .IP "callback/watcher invocation" 4 |
4628 | .IX Item "callback invocation" |
5047 | .IX Item "callback/watcher invocation" |
4629 | The act of calling the callback associated with a watcher. |
5048 | The act of calling the callback associated with a watcher. |
4630 | .IP "event" 4 |
5049 | .IP "event" 4 |
4631 | .IX Item "event" |
5050 | .IX Item "event" |
4632 | A change of state of some external event, such as data now being available |
5051 | A change of state of some external event, such as data now being available |
4633 | for reading on a file descriptor, time having passed or simply not having |
5052 | for reading on a file descriptor, time having passed or simply not having |
4634 | any other events happening anymore. |
5053 | any other events happening anymore. |
4635 | .Sp |
5054 | .Sp |
4636 | In libev, events are represented as single bits (such as \f(CW\*(C`EV_READ\*(C'\fR or |
5055 | In libev, events are represented as single bits (such as \f(CW\*(C`EV_READ\*(C'\fR or |
4637 | \&\f(CW\*(C`EV_TIMEOUT\*(C'\fR). |
5056 | \&\f(CW\*(C`EV_TIMER\*(C'\fR). |
4638 | .IP "event library" 4 |
5057 | .IP "event library" 4 |
4639 | .IX Item "event library" |
5058 | .IX Item "event library" |
4640 | A software package implementing an event model and loop. |
5059 | A software package implementing an event model and loop. |
4641 | .IP "event loop" 4 |
5060 | .IP "event loop" 4 |
4642 | .IX Item "event loop" |
5061 | .IX Item "event loop" |
… | |
… | |
4646 | .IX Item "event model" |
5065 | .IX Item "event model" |
4647 | The model used to describe how an event loop handles and processes |
5066 | The model used to describe how an event loop handles and processes |
4648 | watchers and events. |
5067 | watchers and events. |
4649 | .IP "pending" 4 |
5068 | .IP "pending" 4 |
4650 | .IX Item "pending" |
5069 | .IX Item "pending" |
4651 | A watcher is pending as soon as the corresponding event has been detected, |
5070 | A watcher is pending as soon as the corresponding event has been |
4652 | and stops being pending as soon as the watcher will be invoked or its |
5071 | detected. See \*(L"\s-1WATCHER\s0 \s-1STATES\s0\*(R" for details. |
4653 | pending status is explicitly cleared by the application. |
|
|
4654 | .Sp |
|
|
4655 | A watcher can be pending, but not active. Stopping a watcher also clears |
|
|
4656 | its pending status. |
|
|
4657 | .IP "real time" 4 |
5072 | .IP "real time" 4 |
4658 | .IX Item "real time" |
5073 | .IX Item "real time" |
4659 | The physical time that is observed. It is apparently strictly monotonic :) |
5074 | The physical time that is observed. It is apparently strictly monotonic :) |
4660 | .IP "wall-clock time" 4 |
5075 | .IP "wall-clock time" 4 |
4661 | .IX Item "wall-clock time" |
5076 | .IX Item "wall-clock time" |
… | |
… | |
4664 | clock. |
5079 | clock. |
4665 | .IP "watcher" 4 |
5080 | .IP "watcher" 4 |
4666 | .IX Item "watcher" |
5081 | .IX Item "watcher" |
4667 | A data structure that describes interest in certain events. Watchers need |
5082 | A data structure that describes interest in certain events. Watchers need |
4668 | to be started (attached to an event loop) before they can receive events. |
5083 | to be started (attached to an event loop) before they can receive events. |
4669 | .IP "watcher invocation" 4 |
|
|
4670 | .IX Item "watcher invocation" |
|
|
4671 | The act of calling the callback associated with a watcher. |
|
|
4672 | .SH "AUTHOR" |
5084 | .SH "AUTHOR" |
4673 | .IX Header "AUTHOR" |
5085 | .IX Header "AUTHOR" |
4674 | Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael Magnusson. |
5086 | Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael |
|
|
5087 | Magnusson and Emanuele Giaquinta. |