… | |
… | |
4 | |
4 | |
5 | =head1 SYNOPSIS |
5 | =head1 SYNOPSIS |
6 | |
6 | |
7 | #include <ev.h> |
7 | #include <ev.h> |
8 | |
8 | |
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9 | =head1 EXAMPLE PROGRAM |
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10 | |
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11 | #include <ev.h> |
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12 | |
|
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13 | ev_io stdin_watcher; |
|
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14 | ev_timer timeout_watcher; |
|
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15 | |
|
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16 | /* called when data readable on stdin */ |
|
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17 | static void |
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18 | stdin_cb (EV_P_ struct ev_io *w, int revents) |
|
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19 | { |
|
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20 | /* puts ("stdin ready"); */ |
|
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21 | ev_io_stop (EV_A_ w); /* just a syntax example */ |
|
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22 | ev_unloop (EV_A_ EVUNLOOP_ALL); /* leave all loop calls */ |
|
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23 | } |
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24 | |
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25 | static void |
|
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26 | timeout_cb (EV_P_ struct ev_timer *w, int revents) |
|
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27 | { |
|
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28 | /* puts ("timeout"); */ |
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29 | ev_unloop (EV_A_ EVUNLOOP_ONE); /* leave one loop call */ |
|
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30 | } |
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31 | |
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32 | int |
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33 | main (void) |
|
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34 | { |
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35 | struct ev_loop *loop = ev_default_loop (0); |
|
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36 | |
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37 | /* initialise an io watcher, then start it */ |
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38 | ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ); |
|
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39 | ev_io_start (loop, &stdin_watcher); |
|
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40 | |
|
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41 | /* simple non-repeating 5.5 second timeout */ |
|
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42 | ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.); |
|
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43 | ev_timer_start (loop, &timeout_watcher); |
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44 | |
|
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45 | /* loop till timeout or data ready */ |
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46 | ev_loop (loop, 0); |
|
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47 | |
|
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48 | return 0; |
|
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49 | } |
|
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50 | |
9 | =head1 DESCRIPTION |
51 | =head1 DESCRIPTION |
|
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52 | |
|
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53 | The newest version of this document is also available as a html-formatted |
|
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54 | web page you might find easier to navigate when reading it for the first |
|
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55 | time: L<http://cvs.schmorp.de/libev/ev.html>. |
10 | |
56 | |
11 | Libev is an event loop: you register interest in certain events (such as a |
57 | Libev is an event loop: you register interest in certain events (such as a |
12 | file descriptor being readable or a timeout occuring), and it will manage |
58 | file descriptor being readable or a timeout occuring), and it will manage |
13 | these event sources and provide your program with events. |
59 | these event sources and provide your program with events. |
14 | |
60 | |
… | |
… | |
21 | details of the event, and then hand it over to libev by I<starting> the |
67 | details of the event, and then hand it over to libev by I<starting> the |
22 | watcher. |
68 | watcher. |
23 | |
69 | |
24 | =head1 FEATURES |
70 | =head1 FEATURES |
25 | |
71 | |
26 | Libev supports select, poll, the linux-specific epoll and the bsd-specific |
72 | Libev supports C<select>, C<poll>, the Linux-specific C<epoll>, the |
27 | kqueue mechanisms for file descriptor events, relative timers, absolute |
73 | BSD-specific C<kqueue> and the Solaris-specific event port mechanisms |
28 | timers with customised rescheduling, signal events, process status change |
74 | for file descriptor events (C<ev_io>), the Linux C<inotify> interface |
29 | events (related to SIGCHLD), and event watchers dealing with the event |
75 | (for C<ev_stat>), relative timers (C<ev_timer>), absolute timers |
30 | loop mechanism itself (idle, prepare and check watchers). It also is quite |
76 | with customised rescheduling (C<ev_periodic>), synchronous signals |
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77 | (C<ev_signal>), process status change events (C<ev_child>), and event |
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78 | watchers dealing with the event loop mechanism itself (C<ev_idle>, |
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79 | C<ev_embed>, C<ev_prepare> and C<ev_check> watchers) as well as |
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80 | file watchers (C<ev_stat>) and even limited support for fork events |
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81 | (C<ev_fork>). |
|
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82 | |
|
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83 | It also is quite fast (see this |
31 | fast (see this L<benchmark|http://libev.schmorp.de/bench.html> comparing |
84 | L<benchmark|http://libev.schmorp.de/bench.html> comparing it to libevent |
32 | it to libevent for example). |
85 | for example). |
33 | |
86 | |
34 | =head1 CONVENTIONS |
87 | =head1 CONVENTIONS |
35 | |
88 | |
36 | Libev is very configurable. In this manual the default configuration |
89 | Libev is very configurable. In this manual the default configuration will |
37 | will be described, which supports multiple event loops. For more info |
90 | be described, which supports multiple event loops. For more info about |
38 | about various configuration options please have a look at the file |
91 | various configuration options please have a look at B<EMBED> section in |
39 | F<README.embed> in the libev distribution. If libev was configured without |
92 | this manual. If libev was configured without support for multiple event |
40 | support for multiple event loops, then all functions taking an initial |
93 | loops, then all functions taking an initial argument of name C<loop> |
41 | argument of name C<loop> (which is always of type C<struct ev_loop *>) |
94 | (which is always of type C<struct ev_loop *>) will not have this argument. |
42 | will not have this argument. |
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43 | |
95 | |
44 | =head1 TIME REPRESENTATION |
96 | =head1 TIME REPRESENTATION |
45 | |
97 | |
46 | Libev represents time as a single floating point number, representing the |
98 | Libev represents time as a single floating point number, representing the |
47 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
99 | (fractional) number of seconds since the (POSIX) epoch (somewhere near |
48 | the beginning of 1970, details are complicated, don't ask). This type is |
100 | the beginning of 1970, details are complicated, don't ask). This type is |
49 | called C<ev_tstamp>, which is what you should use too. It usually aliases |
101 | called C<ev_tstamp>, which is what you should use too. It usually aliases |
50 | to the C<double> type in C, and when you need to do any calculations on |
102 | to the C<double> type in C, and when you need to do any calculations on |
51 | it, you should treat it as such. |
103 | it, you should treat it as some floatingpoint value. Unlike the name |
52 | |
104 | component C<stamp> might indicate, it is also used for time differences |
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105 | throughout libev. |
53 | |
106 | |
54 | =head1 GLOBAL FUNCTIONS |
107 | =head1 GLOBAL FUNCTIONS |
55 | |
108 | |
56 | These functions can be called anytime, even before initialising the |
109 | These functions can be called anytime, even before initialising the |
57 | library in any way. |
110 | library in any way. |
… | |
… | |
66 | |
119 | |
67 | =item int ev_version_major () |
120 | =item int ev_version_major () |
68 | |
121 | |
69 | =item int ev_version_minor () |
122 | =item int ev_version_minor () |
70 | |
123 | |
71 | You can find out the major and minor version numbers of the library |
124 | You can find out the major and minor ABI version numbers of the library |
72 | you linked against by calling the functions C<ev_version_major> and |
125 | you linked against by calling the functions C<ev_version_major> and |
73 | C<ev_version_minor>. If you want, you can compare against the global |
126 | C<ev_version_minor>. If you want, you can compare against the global |
74 | symbols C<EV_VERSION_MAJOR> and C<EV_VERSION_MINOR>, which specify the |
127 | symbols C<EV_VERSION_MAJOR> and C<EV_VERSION_MINOR>, which specify the |
75 | version of the library your program was compiled against. |
128 | version of the library your program was compiled against. |
76 | |
129 | |
|
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130 | These version numbers refer to the ABI version of the library, not the |
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131 | release version. |
|
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132 | |
77 | Usually, it's a good idea to terminate if the major versions mismatch, |
133 | Usually, it's a good idea to terminate if the major versions mismatch, |
78 | as this indicates an incompatible change. Minor versions are usually |
134 | as this indicates an incompatible change. Minor versions are usually |
79 | compatible to older versions, so a larger minor version alone is usually |
135 | compatible to older versions, so a larger minor version alone is usually |
80 | not a problem. |
136 | not a problem. |
81 | |
137 | |
82 | Example: make sure we haven't accidentally been linked against the wrong |
138 | Example: Make sure we haven't accidentally been linked against the wrong |
83 | version: |
139 | version. |
84 | |
140 | |
85 | assert (("libev version mismatch", |
141 | assert (("libev version mismatch", |
86 | ev_version_major () == EV_VERSION_MAJOR |
142 | ev_version_major () == EV_VERSION_MAJOR |
87 | && ev_version_minor () >= EV_VERSION_MINOR)); |
143 | && ev_version_minor () >= EV_VERSION_MINOR)); |
88 | |
144 | |
… | |
… | |
118 | |
174 | |
119 | See the description of C<ev_embed> watchers for more info. |
175 | See the description of C<ev_embed> watchers for more info. |
120 | |
176 | |
121 | =item ev_set_allocator (void *(*cb)(void *ptr, long size)) |
177 | =item ev_set_allocator (void *(*cb)(void *ptr, long size)) |
122 | |
178 | |
123 | Sets the allocation function to use (the prototype is similar to the |
179 | Sets the allocation function to use (the prototype is similar - the |
124 | realloc C function, the semantics are identical). It is used to allocate |
180 | semantics is identical - to the realloc C function). It is used to |
125 | and free memory (no surprises here). If it returns zero when memory |
181 | allocate and free memory (no surprises here). If it returns zero when |
126 | needs to be allocated, the library might abort or take some potentially |
182 | memory needs to be allocated, the library might abort or take some |
127 | destructive action. The default is your system realloc function. |
183 | potentially destructive action. The default is your system realloc |
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184 | function. |
128 | |
185 | |
129 | You could override this function in high-availability programs to, say, |
186 | You could override this function in high-availability programs to, say, |
130 | free some memory if it cannot allocate memory, to use a special allocator, |
187 | free some memory if it cannot allocate memory, to use a special allocator, |
131 | or even to sleep a while and retry until some memory is available. |
188 | or even to sleep a while and retry until some memory is available. |
132 | |
189 | |
133 | Example: replace the libev allocator with one that waits a bit and then |
190 | Example: Replace the libev allocator with one that waits a bit and then |
134 | retries: better than mine). |
191 | retries). |
135 | |
192 | |
136 | static void * |
193 | static void * |
137 | persistent_realloc (void *ptr, long size) |
194 | persistent_realloc (void *ptr, size_t size) |
138 | { |
195 | { |
139 | for (;;) |
196 | for (;;) |
140 | { |
197 | { |
141 | void *newptr = realloc (ptr, size); |
198 | void *newptr = realloc (ptr, size); |
142 | |
199 | |
… | |
… | |
158 | callback is set, then libev will expect it to remedy the sitution, no |
215 | callback is set, then libev will expect it to remedy the sitution, no |
159 | matter what, when it returns. That is, libev will generally retry the |
216 | matter what, when it returns. That is, libev will generally retry the |
160 | requested operation, or, if the condition doesn't go away, do bad stuff |
217 | requested operation, or, if the condition doesn't go away, do bad stuff |
161 | (such as abort). |
218 | (such as abort). |
162 | |
219 | |
163 | Example: do the same thing as libev does internally: |
220 | Example: This is basically the same thing that libev does internally, too. |
164 | |
221 | |
165 | static void |
222 | static void |
166 | fatal_error (const char *msg) |
223 | fatal_error (const char *msg) |
167 | { |
224 | { |
168 | perror (msg); |
225 | perror (msg); |
… | |
… | |
218 | C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will |
275 | C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will |
219 | override the flags completely if it is found in the environment. This is |
276 | override the flags completely if it is found in the environment. This is |
220 | useful to try out specific backends to test their performance, or to work |
277 | useful to try out specific backends to test their performance, or to work |
221 | around bugs. |
278 | around bugs. |
222 | |
279 | |
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280 | =item C<EVFLAG_FORKCHECK> |
|
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281 | |
|
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282 | Instead of calling C<ev_default_fork> or C<ev_loop_fork> manually after |
|
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283 | a fork, you can also make libev check for a fork in each iteration by |
|
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284 | enabling this flag. |
|
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285 | |
|
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286 | This works by calling C<getpid ()> on every iteration of the loop, |
|
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287 | and thus this might slow down your event loop if you do a lot of loop |
|
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288 | iterations and little real work, but is usually not noticeable (on my |
|
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289 | Linux system for example, C<getpid> is actually a simple 5-insn sequence |
|
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290 | without a syscall and thus I<very> fast, but my Linux system also has |
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291 | C<pthread_atfork> which is even faster). |
|
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292 | |
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293 | The big advantage of this flag is that you can forget about fork (and |
|
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294 | forget about forgetting to tell libev about forking) when you use this |
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295 | flag. |
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296 | |
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297 | This flag setting cannot be overriden or specified in the C<LIBEV_FLAGS> |
|
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298 | environment variable. |
|
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299 | |
223 | =item C<EVBACKEND_SELECT> (value 1, portable select backend) |
300 | =item C<EVBACKEND_SELECT> (value 1, portable select backend) |
224 | |
301 | |
225 | This is your standard select(2) backend. Not I<completely> standard, as |
302 | This is your standard select(2) backend. Not I<completely> standard, as |
226 | libev tries to roll its own fd_set with no limits on the number of fds, |
303 | libev tries to roll its own fd_set with no limits on the number of fds, |
227 | but if that fails, expect a fairly low limit on the number of fds when |
304 | but if that fails, expect a fairly low limit on the number of fds when |
… | |
… | |
314 | Similar to C<ev_default_loop>, but always creates a new event loop that is |
391 | Similar to C<ev_default_loop>, but always creates a new event loop that is |
315 | always distinct from the default loop. Unlike the default loop, it cannot |
392 | always distinct from the default loop. Unlike the default loop, it cannot |
316 | handle signal and child watchers, and attempts to do so will be greeted by |
393 | handle signal and child watchers, and attempts to do so will be greeted by |
317 | undefined behaviour (or a failed assertion if assertions are enabled). |
394 | undefined behaviour (or a failed assertion if assertions are enabled). |
318 | |
395 | |
319 | Example: try to create a event loop that uses epoll and nothing else. |
396 | Example: Try to create a event loop that uses epoll and nothing else. |
320 | |
397 | |
321 | struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
398 | struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
322 | if (!epoller) |
399 | if (!epoller) |
323 | fatal ("no epoll found here, maybe it hides under your chair"); |
400 | fatal ("no epoll found here, maybe it hides under your chair"); |
324 | |
401 | |
… | |
… | |
327 | Destroys the default loop again (frees all memory and kernel state |
404 | Destroys the default loop again (frees all memory and kernel state |
328 | etc.). None of the active event watchers will be stopped in the normal |
405 | etc.). None of the active event watchers will be stopped in the normal |
329 | sense, so e.g. C<ev_is_active> might still return true. It is your |
406 | sense, so e.g. C<ev_is_active> might still return true. It is your |
330 | responsibility to either stop all watchers cleanly yoursef I<before> |
407 | responsibility to either stop all watchers cleanly yoursef I<before> |
331 | calling this function, or cope with the fact afterwards (which is usually |
408 | calling this function, or cope with the fact afterwards (which is usually |
332 | the easiest thing, youc na just ignore the watchers and/or C<free ()> them |
409 | the easiest thing, you can just ignore the watchers and/or C<free ()> them |
333 | for example). |
410 | for example). |
|
|
411 | |
|
|
412 | Not that certain global state, such as signal state, will not be freed by |
|
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413 | this function, and related watchers (such as signal and child watchers) |
|
|
414 | would need to be stopped manually. |
|
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415 | |
|
|
416 | In general it is not advisable to call this function except in the |
|
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417 | rare occasion where you really need to free e.g. the signal handling |
|
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418 | pipe fds. If you need dynamically allocated loops it is better to use |
|
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419 | C<ev_loop_new> and C<ev_loop_destroy>). |
334 | |
420 | |
335 | =item ev_loop_destroy (loop) |
421 | =item ev_loop_destroy (loop) |
336 | |
422 | |
337 | Like C<ev_default_destroy>, but destroys an event loop created by an |
423 | Like C<ev_default_destroy>, but destroys an event loop created by an |
338 | earlier call to C<ev_loop_new>. |
424 | earlier call to C<ev_loop_new>. |
… | |
… | |
361 | =item ev_loop_fork (loop) |
447 | =item ev_loop_fork (loop) |
362 | |
448 | |
363 | Like C<ev_default_fork>, but acts on an event loop created by |
449 | Like C<ev_default_fork>, but acts on an event loop created by |
364 | C<ev_loop_new>. Yes, you have to call this on every allocated event loop |
450 | C<ev_loop_new>. Yes, you have to call this on every allocated event loop |
365 | after fork, and how you do this is entirely your own problem. |
451 | after fork, and how you do this is entirely your own problem. |
|
|
452 | |
|
|
453 | =item unsigned int ev_loop_count (loop) |
|
|
454 | |
|
|
455 | Returns the count of loop iterations for the loop, which is identical to |
|
|
456 | the number of times libev did poll for new events. It starts at C<0> and |
|
|
457 | happily wraps around with enough iterations. |
|
|
458 | |
|
|
459 | This value can sometimes be useful as a generation counter of sorts (it |
|
|
460 | "ticks" the number of loop iterations), as it roughly corresponds with |
|
|
461 | C<ev_prepare> and C<ev_check> calls. |
366 | |
462 | |
367 | =item unsigned int ev_backend (loop) |
463 | =item unsigned int ev_backend (loop) |
368 | |
464 | |
369 | Returns one of the C<EVBACKEND_*> flags indicating the event backend in |
465 | Returns one of the C<EVBACKEND_*> flags indicating the event backend in |
370 | use. |
466 | use. |
… | |
… | |
404 | libev watchers. However, a pair of C<ev_prepare>/C<ev_check> watchers is |
500 | libev watchers. However, a pair of C<ev_prepare>/C<ev_check> watchers is |
405 | usually a better approach for this kind of thing. |
501 | usually a better approach for this kind of thing. |
406 | |
502 | |
407 | Here are the gory details of what C<ev_loop> does: |
503 | Here are the gory details of what C<ev_loop> does: |
408 | |
504 | |
|
|
505 | - Before the first iteration, call any pending watchers. |
409 | * If there are no active watchers (reference count is zero), return. |
506 | * If there are no active watchers (reference count is zero), return. |
410 | - Queue prepare watchers and then call all outstanding watchers. |
507 | - Queue all prepare watchers and then call all outstanding watchers. |
411 | - If we have been forked, recreate the kernel state. |
508 | - If we have been forked, recreate the kernel state. |
412 | - Update the kernel state with all outstanding changes. |
509 | - Update the kernel state with all outstanding changes. |
413 | - Update the "event loop time". |
510 | - Update the "event loop time". |
414 | - Calculate for how long to block. |
511 | - Calculate for how long to block. |
415 | - Block the process, waiting for any events. |
512 | - Block the process, waiting for any events. |
… | |
… | |
423 | Signals and child watchers are implemented as I/O watchers, and will |
520 | Signals and child watchers are implemented as I/O watchers, and will |
424 | be handled here by queueing them when their watcher gets executed. |
521 | be handled here by queueing them when their watcher gets executed. |
425 | - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
522 | - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK |
426 | were used, return, otherwise continue with step *. |
523 | were used, return, otherwise continue with step *. |
427 | |
524 | |
428 | Example: queue some jobs and then loop until no events are outsanding |
525 | Example: Queue some jobs and then loop until no events are outsanding |
429 | anymore. |
526 | anymore. |
430 | |
527 | |
431 | ... queue jobs here, make sure they register event watchers as long |
528 | ... queue jobs here, make sure they register event watchers as long |
432 | ... as they still have work to do (even an idle watcher will do..) |
529 | ... as they still have work to do (even an idle watcher will do..) |
433 | ev_loop (my_loop, 0); |
530 | ev_loop (my_loop, 0); |
… | |
… | |
453 | visible to the libev user and should not keep C<ev_loop> from exiting if |
550 | visible to the libev user and should not keep C<ev_loop> from exiting if |
454 | no event watchers registered by it are active. It is also an excellent |
551 | no event watchers registered by it are active. It is also an excellent |
455 | way to do this for generic recurring timers or from within third-party |
552 | way to do this for generic recurring timers or from within third-party |
456 | libraries. Just remember to I<unref after start> and I<ref before stop>. |
553 | libraries. Just remember to I<unref after start> and I<ref before stop>. |
457 | |
554 | |
458 | Example: create a signal watcher, but keep it from keeping C<ev_loop> |
555 | Example: Create a signal watcher, but keep it from keeping C<ev_loop> |
459 | running when nothing else is active. |
556 | running when nothing else is active. |
460 | |
557 | |
461 | struct dv_signal exitsig; |
558 | struct ev_signal exitsig; |
462 | ev_signal_init (&exitsig, sig_cb, SIGINT); |
559 | ev_signal_init (&exitsig, sig_cb, SIGINT); |
463 | ev_signal_start (myloop, &exitsig); |
560 | ev_signal_start (loop, &exitsig); |
464 | evf_unref (myloop); |
561 | evf_unref (loop); |
465 | |
562 | |
466 | Example: for some weird reason, unregister the above signal handler again. |
563 | Example: For some weird reason, unregister the above signal handler again. |
467 | |
564 | |
468 | ev_ref (myloop); |
565 | ev_ref (loop); |
469 | ev_signal_stop (myloop, &exitsig); |
566 | ev_signal_stop (loop, &exitsig); |
470 | |
567 | |
471 | =back |
568 | =back |
472 | |
569 | |
473 | |
570 | |
474 | =head1 ANATOMY OF A WATCHER |
571 | =head1 ANATOMY OF A WATCHER |
… | |
… | |
544 | The signal specified in the C<ev_signal> watcher has been received by a thread. |
641 | The signal specified in the C<ev_signal> watcher has been received by a thread. |
545 | |
642 | |
546 | =item C<EV_CHILD> |
643 | =item C<EV_CHILD> |
547 | |
644 | |
548 | The pid specified in the C<ev_child> watcher has received a status change. |
645 | The pid specified in the C<ev_child> watcher has received a status change. |
|
|
646 | |
|
|
647 | =item C<EV_STAT> |
|
|
648 | |
|
|
649 | The path specified in the C<ev_stat> watcher changed its attributes somehow. |
549 | |
650 | |
550 | =item C<EV_IDLE> |
651 | =item C<EV_IDLE> |
551 | |
652 | |
552 | The C<ev_idle> watcher has determined that you have nothing better to do. |
653 | The C<ev_idle> watcher has determined that you have nothing better to do. |
553 | |
654 | |
… | |
… | |
561 | received events. Callbacks of both watcher types can start and stop as |
662 | received events. Callbacks of both watcher types can start and stop as |
562 | many watchers as they want, and all of them will be taken into account |
663 | many watchers as they want, and all of them will be taken into account |
563 | (for example, a C<ev_prepare> watcher might start an idle watcher to keep |
664 | (for example, a C<ev_prepare> watcher might start an idle watcher to keep |
564 | C<ev_loop> from blocking). |
665 | C<ev_loop> from blocking). |
565 | |
666 | |
|
|
667 | =item C<EV_EMBED> |
|
|
668 | |
|
|
669 | The embedded event loop specified in the C<ev_embed> watcher needs attention. |
|
|
670 | |
|
|
671 | =item C<EV_FORK> |
|
|
672 | |
|
|
673 | The event loop has been resumed in the child process after fork (see |
|
|
674 | C<ev_fork>). |
|
|
675 | |
566 | =item C<EV_ERROR> |
676 | =item C<EV_ERROR> |
567 | |
677 | |
568 | An unspecified error has occured, the watcher has been stopped. This might |
678 | An unspecified error has occured, the watcher has been stopped. This might |
569 | happen because the watcher could not be properly started because libev |
679 | happen because the watcher could not be properly started because libev |
570 | ran out of memory, a file descriptor was found to be closed or any other |
680 | ran out of memory, a file descriptor was found to be closed or any other |
… | |
… | |
641 | =item bool ev_is_pending (ev_TYPE *watcher) |
751 | =item bool ev_is_pending (ev_TYPE *watcher) |
642 | |
752 | |
643 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
753 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
644 | events but its callback has not yet been invoked). As long as a watcher |
754 | events but its callback has not yet been invoked). As long as a watcher |
645 | is pending (but not active) you must not call an init function on it (but |
755 | is pending (but not active) you must not call an init function on it (but |
646 | C<ev_TYPE_set> is safe) and you must make sure the watcher is available to |
756 | C<ev_TYPE_set> is safe), you must not change its priority, and you must |
647 | libev (e.g. you cnanot C<free ()> it). |
757 | make sure the watcher is available to libev (e.g. you cannot C<free ()> |
|
|
758 | it). |
648 | |
759 | |
649 | =item callback = ev_cb (ev_TYPE *watcher) |
760 | =item callback ev_cb (ev_TYPE *watcher) |
650 | |
761 | |
651 | Returns the callback currently set on the watcher. |
762 | Returns the callback currently set on the watcher. |
652 | |
763 | |
653 | =item ev_cb_set (ev_TYPE *watcher, callback) |
764 | =item ev_cb_set (ev_TYPE *watcher, callback) |
654 | |
765 | |
655 | Change the callback. You can change the callback at virtually any time |
766 | Change the callback. You can change the callback at virtually any time |
656 | (modulo threads). |
767 | (modulo threads). |
|
|
768 | |
|
|
769 | =item ev_set_priority (ev_TYPE *watcher, priority) |
|
|
770 | |
|
|
771 | =item int ev_priority (ev_TYPE *watcher) |
|
|
772 | |
|
|
773 | Set and query the priority of the watcher. The priority is a small |
|
|
774 | integer between C<EV_MAXPRI> (default: C<2>) and C<EV_MINPRI> |
|
|
775 | (default: C<-2>). Pending watchers with higher priority will be invoked |
|
|
776 | before watchers with lower priority, but priority will not keep watchers |
|
|
777 | from being executed (except for C<ev_idle> watchers). |
|
|
778 | |
|
|
779 | This means that priorities are I<only> used for ordering callback |
|
|
780 | invocation after new events have been received. This is useful, for |
|
|
781 | example, to reduce latency after idling, or more often, to bind two |
|
|
782 | watchers on the same event and make sure one is called first. |
|
|
783 | |
|
|
784 | If you need to suppress invocation when higher priority events are pending |
|
|
785 | you need to look at C<ev_idle> watchers, which provide this functionality. |
|
|
786 | |
|
|
787 | You I<must not> change the priority of a watcher as long as it is active or |
|
|
788 | pending. |
|
|
789 | |
|
|
790 | The default priority used by watchers when no priority has been set is |
|
|
791 | always C<0>, which is supposed to not be too high and not be too low :). |
|
|
792 | |
|
|
793 | Setting a priority outside the range of C<EV_MINPRI> to C<EV_MAXPRI> is |
|
|
794 | fine, as long as you do not mind that the priority value you query might |
|
|
795 | or might not have been adjusted to be within valid range. |
|
|
796 | |
|
|
797 | =item ev_invoke (loop, ev_TYPE *watcher, int revents) |
|
|
798 | |
|
|
799 | Invoke the C<watcher> with the given C<loop> and C<revents>. Neither |
|
|
800 | C<loop> nor C<revents> need to be valid as long as the watcher callback |
|
|
801 | can deal with that fact. |
|
|
802 | |
|
|
803 | =item int ev_clear_pending (loop, ev_TYPE *watcher) |
|
|
804 | |
|
|
805 | If the watcher is pending, this function returns clears its pending status |
|
|
806 | and returns its C<revents> bitset (as if its callback was invoked). If the |
|
|
807 | watcher isn't pending it does nothing and returns C<0>. |
657 | |
808 | |
658 | =back |
809 | =back |
659 | |
810 | |
660 | |
811 | |
661 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
812 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
… | |
… | |
682 | { |
833 | { |
683 | struct my_io *w = (struct my_io *)w_; |
834 | struct my_io *w = (struct my_io *)w_; |
684 | ... |
835 | ... |
685 | } |
836 | } |
686 | |
837 | |
687 | More interesting and less C-conformant ways of catsing your callback type |
838 | More interesting and less C-conformant ways of casting your callback type |
688 | have been omitted.... |
839 | instead have been omitted. |
|
|
840 | |
|
|
841 | Another common scenario is having some data structure with multiple |
|
|
842 | watchers: |
|
|
843 | |
|
|
844 | struct my_biggy |
|
|
845 | { |
|
|
846 | int some_data; |
|
|
847 | ev_timer t1; |
|
|
848 | ev_timer t2; |
|
|
849 | } |
|
|
850 | |
|
|
851 | In this case getting the pointer to C<my_biggy> is a bit more complicated, |
|
|
852 | you need to use C<offsetof>: |
|
|
853 | |
|
|
854 | #include <stddef.h> |
|
|
855 | |
|
|
856 | static void |
|
|
857 | t1_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
858 | { |
|
|
859 | struct my_biggy big = (struct my_biggy * |
|
|
860 | (((char *)w) - offsetof (struct my_biggy, t1)); |
|
|
861 | } |
|
|
862 | |
|
|
863 | static void |
|
|
864 | t2_cb (EV_P_ struct ev_timer *w, int revents) |
|
|
865 | { |
|
|
866 | struct my_biggy big = (struct my_biggy * |
|
|
867 | (((char *)w) - offsetof (struct my_biggy, t2)); |
|
|
868 | } |
689 | |
869 | |
690 | |
870 | |
691 | =head1 WATCHER TYPES |
871 | =head1 WATCHER TYPES |
692 | |
872 | |
693 | This section describes each watcher in detail, but will not repeat |
873 | This section describes each watcher in detail, but will not repeat |
694 | information given in the last section. |
874 | information given in the last section. Any initialisation/set macros, |
|
|
875 | functions and members specific to the watcher type are explained. |
|
|
876 | |
|
|
877 | Members are additionally marked with either I<[read-only]>, meaning that, |
|
|
878 | while the watcher is active, you can look at the member and expect some |
|
|
879 | sensible content, but you must not modify it (you can modify it while the |
|
|
880 | watcher is stopped to your hearts content), or I<[read-write]>, which |
|
|
881 | means you can expect it to have some sensible content while the watcher |
|
|
882 | is active, but you can also modify it. Modifying it may not do something |
|
|
883 | sensible or take immediate effect (or do anything at all), but libev will |
|
|
884 | not crash or malfunction in any way. |
695 | |
885 | |
696 | |
886 | |
697 | =head2 C<ev_io> - is this file descriptor readable or writable? |
887 | =head2 C<ev_io> - is this file descriptor readable or writable? |
698 | |
888 | |
699 | I/O watchers check whether a file descriptor is readable or writable |
889 | I/O watchers check whether a file descriptor is readable or writable |
… | |
… | |
728 | it is best to always use non-blocking I/O: An extra C<read>(2) returning |
918 | it is best to always use non-blocking I/O: An extra C<read>(2) returning |
729 | C<EAGAIN> is far preferable to a program hanging until some data arrives. |
919 | C<EAGAIN> is far preferable to a program hanging until some data arrives. |
730 | |
920 | |
731 | If you cannot run the fd in non-blocking mode (for example you should not |
921 | If you cannot run the fd in non-blocking mode (for example you should not |
732 | play around with an Xlib connection), then you have to seperately re-test |
922 | play around with an Xlib connection), then you have to seperately re-test |
733 | wether a file descriptor is really ready with a known-to-be good interface |
923 | whether a file descriptor is really ready with a known-to-be good interface |
734 | such as poll (fortunately in our Xlib example, Xlib already does this on |
924 | such as poll (fortunately in our Xlib example, Xlib already does this on |
735 | its own, so its quite safe to use). |
925 | its own, so its quite safe to use). |
|
|
926 | |
|
|
927 | =head3 The special problem of disappearing file descriptors |
|
|
928 | |
|
|
929 | Some backends (e.g kqueue, epoll) need to be told about closing a file |
|
|
930 | descriptor (either by calling C<close> explicitly or by any other means, |
|
|
931 | such as C<dup>). The reason is that you register interest in some file |
|
|
932 | descriptor, but when it goes away, the operating system will silently drop |
|
|
933 | this interest. If another file descriptor with the same number then is |
|
|
934 | registered with libev, there is no efficient way to see that this is, in |
|
|
935 | fact, a different file descriptor. |
|
|
936 | |
|
|
937 | To avoid having to explicitly tell libev about such cases, libev follows |
|
|
938 | the following policy: Each time C<ev_io_set> is being called, libev |
|
|
939 | will assume that this is potentially a new file descriptor, otherwise |
|
|
940 | it is assumed that the file descriptor stays the same. That means that |
|
|
941 | you I<have> to call C<ev_io_set> (or C<ev_io_init>) when you change the |
|
|
942 | descriptor even if the file descriptor number itself did not change. |
|
|
943 | |
|
|
944 | This is how one would do it normally anyway, the important point is that |
|
|
945 | the libev application should not optimise around libev but should leave |
|
|
946 | optimisations to libev. |
|
|
947 | |
|
|
948 | |
|
|
949 | =head3 Watcher-Specific Functions |
736 | |
950 | |
737 | =over 4 |
951 | =over 4 |
738 | |
952 | |
739 | =item ev_io_init (ev_io *, callback, int fd, int events) |
953 | =item ev_io_init (ev_io *, callback, int fd, int events) |
740 | |
954 | |
… | |
… | |
742 | |
956 | |
743 | Configures an C<ev_io> watcher. The C<fd> is the file descriptor to |
957 | Configures an C<ev_io> watcher. The C<fd> is the file descriptor to |
744 | rceeive events for and events is either C<EV_READ>, C<EV_WRITE> or |
958 | rceeive events for and events is either C<EV_READ>, C<EV_WRITE> or |
745 | C<EV_READ | EV_WRITE> to receive the given events. |
959 | C<EV_READ | EV_WRITE> to receive the given events. |
746 | |
960 | |
|
|
961 | =item int fd [read-only] |
|
|
962 | |
|
|
963 | The file descriptor being watched. |
|
|
964 | |
|
|
965 | =item int events [read-only] |
|
|
966 | |
|
|
967 | The events being watched. |
|
|
968 | |
747 | =back |
969 | =back |
748 | |
970 | |
749 | Example: call C<stdin_readable_cb> when STDIN_FILENO has become, well |
971 | Example: Call C<stdin_readable_cb> when STDIN_FILENO has become, well |
750 | readable, but only once. Since it is likely line-buffered, you could |
972 | readable, but only once. Since it is likely line-buffered, you could |
751 | attempt to read a whole line in the callback: |
973 | attempt to read a whole line in the callback. |
752 | |
974 | |
753 | static void |
975 | static void |
754 | stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
976 | stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
755 | { |
977 | { |
756 | ev_io_stop (loop, w); |
978 | ev_io_stop (loop, w); |
… | |
… | |
786 | |
1008 | |
787 | The callback is guarenteed to be invoked only when its timeout has passed, |
1009 | The callback is guarenteed to be invoked only when its timeout has passed, |
788 | but if multiple timers become ready during the same loop iteration then |
1010 | but if multiple timers become ready during the same loop iteration then |
789 | order of execution is undefined. |
1011 | order of execution is undefined. |
790 | |
1012 | |
|
|
1013 | =head3 Watcher-Specific Functions and Data Members |
|
|
1014 | |
791 | =over 4 |
1015 | =over 4 |
792 | |
1016 | |
793 | =item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat) |
1017 | =item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat) |
794 | |
1018 | |
795 | =item ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat) |
1019 | =item ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat) |
… | |
… | |
808 | =item ev_timer_again (loop) |
1032 | =item ev_timer_again (loop) |
809 | |
1033 | |
810 | This will act as if the timer timed out and restart it again if it is |
1034 | This will act as if the timer timed out and restart it again if it is |
811 | repeating. The exact semantics are: |
1035 | repeating. The exact semantics are: |
812 | |
1036 | |
|
|
1037 | If the timer is pending, its pending status is cleared. |
|
|
1038 | |
813 | If the timer is started but nonrepeating, stop it. |
1039 | If the timer is started but nonrepeating, stop it (as if it timed out). |
814 | |
1040 | |
815 | If the timer is repeating, either start it if necessary (with the repeat |
1041 | If the timer is repeating, either start it if necessary (with the |
816 | value), or reset the running timer to the repeat value. |
1042 | C<repeat> value), or reset the running timer to the C<repeat> value. |
817 | |
1043 | |
818 | This sounds a bit complicated, but here is a useful and typical |
1044 | This sounds a bit complicated, but here is a useful and typical |
819 | example: Imagine you have a tcp connection and you want a so-called idle |
1045 | example: Imagine you have a tcp connection and you want a so-called idle |
820 | timeout, that is, you want to be called when there have been, say, 60 |
1046 | timeout, that is, you want to be called when there have been, say, 60 |
821 | seconds of inactivity on the socket. The easiest way to do this is to |
1047 | seconds of inactivity on the socket. The easiest way to do this is to |
822 | configure an C<ev_timer> with after=repeat=60 and calling ev_timer_again each |
1048 | configure an C<ev_timer> with a C<repeat> value of C<60> and then call |
823 | time you successfully read or write some data. If you go into an idle |
1049 | C<ev_timer_again> each time you successfully read or write some data. If |
824 | state where you do not expect data to travel on the socket, you can stop |
1050 | you go into an idle state where you do not expect data to travel on the |
825 | the timer, and again will automatically restart it if need be. |
1051 | socket, you can C<ev_timer_stop> the timer, and C<ev_timer_again> will |
|
|
1052 | automatically restart it if need be. |
|
|
1053 | |
|
|
1054 | That means you can ignore the C<after> value and C<ev_timer_start> |
|
|
1055 | altogether and only ever use the C<repeat> value and C<ev_timer_again>: |
|
|
1056 | |
|
|
1057 | ev_timer_init (timer, callback, 0., 5.); |
|
|
1058 | ev_timer_again (loop, timer); |
|
|
1059 | ... |
|
|
1060 | timer->again = 17.; |
|
|
1061 | ev_timer_again (loop, timer); |
|
|
1062 | ... |
|
|
1063 | timer->again = 10.; |
|
|
1064 | ev_timer_again (loop, timer); |
|
|
1065 | |
|
|
1066 | This is more slightly efficient then stopping/starting the timer each time |
|
|
1067 | you want to modify its timeout value. |
|
|
1068 | |
|
|
1069 | =item ev_tstamp repeat [read-write] |
|
|
1070 | |
|
|
1071 | The current C<repeat> value. Will be used each time the watcher times out |
|
|
1072 | or C<ev_timer_again> is called and determines the next timeout (if any), |
|
|
1073 | which is also when any modifications are taken into account. |
826 | |
1074 | |
827 | =back |
1075 | =back |
828 | |
1076 | |
829 | Example: create a timer that fires after 60 seconds. |
1077 | Example: Create a timer that fires after 60 seconds. |
830 | |
1078 | |
831 | static void |
1079 | static void |
832 | one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1080 | one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
833 | { |
1081 | { |
834 | .. one minute over, w is actually stopped right here |
1082 | .. one minute over, w is actually stopped right here |
… | |
… | |
836 | |
1084 | |
837 | struct ev_timer mytimer; |
1085 | struct ev_timer mytimer; |
838 | ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
1086 | ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
839 | ev_timer_start (loop, &mytimer); |
1087 | ev_timer_start (loop, &mytimer); |
840 | |
1088 | |
841 | Example: create a timeout timer that times out after 10 seconds of |
1089 | Example: Create a timeout timer that times out after 10 seconds of |
842 | inactivity. |
1090 | inactivity. |
843 | |
1091 | |
844 | static void |
1092 | static void |
845 | timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
1093 | timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents) |
846 | { |
1094 | { |
… | |
… | |
866 | but on wallclock time (absolute time). You can tell a periodic watcher |
1114 | but on wallclock time (absolute time). You can tell a periodic watcher |
867 | to trigger "at" some specific point in time. For example, if you tell a |
1115 | to trigger "at" some specific point in time. For example, if you tell a |
868 | periodic watcher to trigger in 10 seconds (by specifiying e.g. C<ev_now () |
1116 | periodic watcher to trigger in 10 seconds (by specifiying e.g. C<ev_now () |
869 | + 10.>) and then reset your system clock to the last year, then it will |
1117 | + 10.>) and then reset your system clock to the last year, then it will |
870 | take a year to trigger the event (unlike an C<ev_timer>, which would trigger |
1118 | take a year to trigger the event (unlike an C<ev_timer>, which would trigger |
871 | roughly 10 seconds later and of course not if you reset your system time |
1119 | roughly 10 seconds later). |
872 | again). |
|
|
873 | |
1120 | |
874 | They can also be used to implement vastly more complex timers, such as |
1121 | They can also be used to implement vastly more complex timers, such as |
875 | triggering an event on eahc midnight, local time. |
1122 | triggering an event on each midnight, local time or other, complicated, |
|
|
1123 | rules. |
876 | |
1124 | |
877 | As with timers, the callback is guarenteed to be invoked only when the |
1125 | As with timers, the callback is guarenteed to be invoked only when the |
878 | time (C<at>) has been passed, but if multiple periodic timers become ready |
1126 | time (C<at>) has been passed, but if multiple periodic timers become ready |
879 | during the same loop iteration then order of execution is undefined. |
1127 | during the same loop iteration then order of execution is undefined. |
880 | |
1128 | |
|
|
1129 | =head3 Watcher-Specific Functions and Data Members |
|
|
1130 | |
881 | =over 4 |
1131 | =over 4 |
882 | |
1132 | |
883 | =item ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb) |
1133 | =item ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb) |
884 | |
1134 | |
885 | =item ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb) |
1135 | =item ev_periodic_set (ev_periodic *, ev_tstamp after, ev_tstamp repeat, reschedule_cb) |
… | |
… | |
887 | Lots of arguments, lets sort it out... There are basically three modes of |
1137 | Lots of arguments, lets sort it out... There are basically three modes of |
888 | operation, and we will explain them from simplest to complex: |
1138 | operation, and we will explain them from simplest to complex: |
889 | |
1139 | |
890 | =over 4 |
1140 | =over 4 |
891 | |
1141 | |
892 | =item * absolute timer (interval = reschedule_cb = 0) |
1142 | =item * absolute timer (at = time, interval = reschedule_cb = 0) |
893 | |
1143 | |
894 | In this configuration the watcher triggers an event at the wallclock time |
1144 | In this configuration the watcher triggers an event at the wallclock time |
895 | C<at> and doesn't repeat. It will not adjust when a time jump occurs, |
1145 | C<at> and doesn't repeat. It will not adjust when a time jump occurs, |
896 | that is, if it is to be run at January 1st 2011 then it will run when the |
1146 | that is, if it is to be run at January 1st 2011 then it will run when the |
897 | system time reaches or surpasses this time. |
1147 | system time reaches or surpasses this time. |
898 | |
1148 | |
899 | =item * non-repeating interval timer (interval > 0, reschedule_cb = 0) |
1149 | =item * non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0) |
900 | |
1150 | |
901 | In this mode the watcher will always be scheduled to time out at the next |
1151 | In this mode the watcher will always be scheduled to time out at the next |
902 | C<at + N * interval> time (for some integer N) and then repeat, regardless |
1152 | C<at + N * interval> time (for some integer N, which can also be negative) |
903 | of any time jumps. |
1153 | and then repeat, regardless of any time jumps. |
904 | |
1154 | |
905 | This can be used to create timers that do not drift with respect to system |
1155 | This can be used to create timers that do not drift with respect to system |
906 | time: |
1156 | time: |
907 | |
1157 | |
908 | ev_periodic_set (&periodic, 0., 3600., 0); |
1158 | ev_periodic_set (&periodic, 0., 3600., 0); |
… | |
… | |
914 | |
1164 | |
915 | Another way to think about it (for the mathematically inclined) is that |
1165 | Another way to think about it (for the mathematically inclined) is that |
916 | C<ev_periodic> will try to run the callback in this mode at the next possible |
1166 | C<ev_periodic> will try to run the callback in this mode at the next possible |
917 | time where C<time = at (mod interval)>, regardless of any time jumps. |
1167 | time where C<time = at (mod interval)>, regardless of any time jumps. |
918 | |
1168 | |
|
|
1169 | For numerical stability it is preferable that the C<at> value is near |
|
|
1170 | C<ev_now ()> (the current time), but there is no range requirement for |
|
|
1171 | this value. |
|
|
1172 | |
919 | =item * manual reschedule mode (reschedule_cb = callback) |
1173 | =item * manual reschedule mode (at and interval ignored, reschedule_cb = callback) |
920 | |
1174 | |
921 | In this mode the values for C<interval> and C<at> are both being |
1175 | In this mode the values for C<interval> and C<at> are both being |
922 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1176 | ignored. Instead, each time the periodic watcher gets scheduled, the |
923 | reschedule callback will be called with the watcher as first, and the |
1177 | reschedule callback will be called with the watcher as first, and the |
924 | current time as second argument. |
1178 | current time as second argument. |
925 | |
1179 | |
926 | NOTE: I<This callback MUST NOT stop or destroy any periodic watcher, |
1180 | NOTE: I<This callback MUST NOT stop or destroy any periodic watcher, |
927 | ever, or make any event loop modifications>. If you need to stop it, |
1181 | ever, or make any event loop modifications>. If you need to stop it, |
928 | return C<now + 1e30> (or so, fudge fudge) and stop it afterwards (e.g. by |
1182 | return C<now + 1e30> (or so, fudge fudge) and stop it afterwards (e.g. by |
929 | starting a prepare watcher). |
1183 | starting an C<ev_prepare> watcher, which is legal). |
930 | |
1184 | |
931 | Its prototype is C<ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
1185 | Its prototype is C<ev_tstamp (*reschedule_cb)(struct ev_periodic *w, |
932 | ev_tstamp now)>, e.g.: |
1186 | ev_tstamp now)>, e.g.: |
933 | |
1187 | |
934 | static ev_tstamp my_rescheduler (struct ev_periodic *w, ev_tstamp now) |
1188 | static ev_tstamp my_rescheduler (struct ev_periodic *w, ev_tstamp now) |
… | |
… | |
957 | Simply stops and restarts the periodic watcher again. This is only useful |
1211 | Simply stops and restarts the periodic watcher again. This is only useful |
958 | when you changed some parameters or the reschedule callback would return |
1212 | when you changed some parameters or the reschedule callback would return |
959 | a different time than the last time it was called (e.g. in a crond like |
1213 | a different time than the last time it was called (e.g. in a crond like |
960 | program when the crontabs have changed). |
1214 | program when the crontabs have changed). |
961 | |
1215 | |
|
|
1216 | =item ev_tstamp offset [read-write] |
|
|
1217 | |
|
|
1218 | When repeating, this contains the offset value, otherwise this is the |
|
|
1219 | absolute point in time (the C<at> value passed to C<ev_periodic_set>). |
|
|
1220 | |
|
|
1221 | Can be modified any time, but changes only take effect when the periodic |
|
|
1222 | timer fires or C<ev_periodic_again> is being called. |
|
|
1223 | |
|
|
1224 | =item ev_tstamp interval [read-write] |
|
|
1225 | |
|
|
1226 | The current interval value. Can be modified any time, but changes only |
|
|
1227 | take effect when the periodic timer fires or C<ev_periodic_again> is being |
|
|
1228 | called. |
|
|
1229 | |
|
|
1230 | =item ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write] |
|
|
1231 | |
|
|
1232 | The current reschedule callback, or C<0>, if this functionality is |
|
|
1233 | switched off. Can be changed any time, but changes only take effect when |
|
|
1234 | the periodic timer fires or C<ev_periodic_again> is being called. |
|
|
1235 | |
|
|
1236 | =item ev_tstamp at [read-only] |
|
|
1237 | |
|
|
1238 | When active, contains the absolute time that the watcher is supposed to |
|
|
1239 | trigger next. |
|
|
1240 | |
962 | =back |
1241 | =back |
963 | |
1242 | |
964 | Example: call a callback every hour, or, more precisely, whenever the |
1243 | Example: Call a callback every hour, or, more precisely, whenever the |
965 | system clock is divisible by 3600. The callback invocation times have |
1244 | system clock is divisible by 3600. The callback invocation times have |
966 | potentially a lot of jittering, but good long-term stability. |
1245 | potentially a lot of jittering, but good long-term stability. |
967 | |
1246 | |
968 | static void |
1247 | static void |
969 | clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
1248 | clock_cb (struct ev_loop *loop, struct ev_io *w, int revents) |
… | |
… | |
973 | |
1252 | |
974 | struct ev_periodic hourly_tick; |
1253 | struct ev_periodic hourly_tick; |
975 | ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1254 | ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
976 | ev_periodic_start (loop, &hourly_tick); |
1255 | ev_periodic_start (loop, &hourly_tick); |
977 | |
1256 | |
978 | Example: the same as above, but use a reschedule callback to do it: |
1257 | Example: The same as above, but use a reschedule callback to do it: |
979 | |
1258 | |
980 | #include <math.h> |
1259 | #include <math.h> |
981 | |
1260 | |
982 | static ev_tstamp |
1261 | static ev_tstamp |
983 | my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
1262 | my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
… | |
… | |
985 | return fmod (now, 3600.) + 3600.; |
1264 | return fmod (now, 3600.) + 3600.; |
986 | } |
1265 | } |
987 | |
1266 | |
988 | ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
1267 | ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb); |
989 | |
1268 | |
990 | Example: call a callback every hour, starting now: |
1269 | Example: Call a callback every hour, starting now: |
991 | |
1270 | |
992 | struct ev_periodic hourly_tick; |
1271 | struct ev_periodic hourly_tick; |
993 | ev_periodic_init (&hourly_tick, clock_cb, |
1272 | ev_periodic_init (&hourly_tick, clock_cb, |
994 | fmod (ev_now (loop), 3600.), 3600., 0); |
1273 | fmod (ev_now (loop), 3600.), 3600., 0); |
995 | ev_periodic_start (loop, &hourly_tick); |
1274 | ev_periodic_start (loop, &hourly_tick); |
… | |
… | |
1007 | with the kernel (thus it coexists with your own signal handlers as long |
1286 | with the kernel (thus it coexists with your own signal handlers as long |
1008 | as you don't register any with libev). Similarly, when the last signal |
1287 | as you don't register any with libev). Similarly, when the last signal |
1009 | watcher for a signal is stopped libev will reset the signal handler to |
1288 | watcher for a signal is stopped libev will reset the signal handler to |
1010 | SIG_DFL (regardless of what it was set to before). |
1289 | SIG_DFL (regardless of what it was set to before). |
1011 | |
1290 | |
|
|
1291 | =head3 Watcher-Specific Functions and Data Members |
|
|
1292 | |
1012 | =over 4 |
1293 | =over 4 |
1013 | |
1294 | |
1014 | =item ev_signal_init (ev_signal *, callback, int signum) |
1295 | =item ev_signal_init (ev_signal *, callback, int signum) |
1015 | |
1296 | |
1016 | =item ev_signal_set (ev_signal *, int signum) |
1297 | =item ev_signal_set (ev_signal *, int signum) |
1017 | |
1298 | |
1018 | Configures the watcher to trigger on the given signal number (usually one |
1299 | Configures the watcher to trigger on the given signal number (usually one |
1019 | of the C<SIGxxx> constants). |
1300 | of the C<SIGxxx> constants). |
1020 | |
1301 | |
|
|
1302 | =item int signum [read-only] |
|
|
1303 | |
|
|
1304 | The signal the watcher watches out for. |
|
|
1305 | |
1021 | =back |
1306 | =back |
1022 | |
1307 | |
1023 | |
1308 | |
1024 | =head2 C<ev_child> - watch out for process status changes |
1309 | =head2 C<ev_child> - watch out for process status changes |
1025 | |
1310 | |
1026 | Child watchers trigger when your process receives a SIGCHLD in response to |
1311 | Child watchers trigger when your process receives a SIGCHLD in response to |
1027 | some child status changes (most typically when a child of yours dies). |
1312 | some child status changes (most typically when a child of yours dies). |
|
|
1313 | |
|
|
1314 | =head3 Watcher-Specific Functions and Data Members |
1028 | |
1315 | |
1029 | =over 4 |
1316 | =over 4 |
1030 | |
1317 | |
1031 | =item ev_child_init (ev_child *, callback, int pid) |
1318 | =item ev_child_init (ev_child *, callback, int pid) |
1032 | |
1319 | |
… | |
… | |
1037 | at the C<rstatus> member of the C<ev_child> watcher structure to see |
1324 | at the C<rstatus> member of the C<ev_child> watcher structure to see |
1038 | the status word (use the macros from C<sys/wait.h> and see your systems |
1325 | the status word (use the macros from C<sys/wait.h> and see your systems |
1039 | C<waitpid> documentation). The C<rpid> member contains the pid of the |
1326 | C<waitpid> documentation). The C<rpid> member contains the pid of the |
1040 | process causing the status change. |
1327 | process causing the status change. |
1041 | |
1328 | |
|
|
1329 | =item int pid [read-only] |
|
|
1330 | |
|
|
1331 | The process id this watcher watches out for, or C<0>, meaning any process id. |
|
|
1332 | |
|
|
1333 | =item int rpid [read-write] |
|
|
1334 | |
|
|
1335 | The process id that detected a status change. |
|
|
1336 | |
|
|
1337 | =item int rstatus [read-write] |
|
|
1338 | |
|
|
1339 | The process exit/trace status caused by C<rpid> (see your systems |
|
|
1340 | C<waitpid> and C<sys/wait.h> documentation for details). |
|
|
1341 | |
1042 | =back |
1342 | =back |
1043 | |
1343 | |
1044 | Example: try to exit cleanly on SIGINT and SIGTERM. |
1344 | Example: Try to exit cleanly on SIGINT and SIGTERM. |
1045 | |
1345 | |
1046 | static void |
1346 | static void |
1047 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1347 | sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents) |
1048 | { |
1348 | { |
1049 | ev_unloop (loop, EVUNLOOP_ALL); |
1349 | ev_unloop (loop, EVUNLOOP_ALL); |
… | |
… | |
1052 | struct ev_signal signal_watcher; |
1352 | struct ev_signal signal_watcher; |
1053 | ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1353 | ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1054 | ev_signal_start (loop, &sigint_cb); |
1354 | ev_signal_start (loop, &sigint_cb); |
1055 | |
1355 | |
1056 | |
1356 | |
|
|
1357 | =head2 C<ev_stat> - did the file attributes just change? |
|
|
1358 | |
|
|
1359 | This watches a filesystem path for attribute changes. That is, it calls |
|
|
1360 | C<stat> regularly (or when the OS says it changed) and sees if it changed |
|
|
1361 | compared to the last time, invoking the callback if it did. |
|
|
1362 | |
|
|
1363 | The path does not need to exist: changing from "path exists" to "path does |
|
|
1364 | not exist" is a status change like any other. The condition "path does |
|
|
1365 | not exist" is signified by the C<st_nlink> field being zero (which is |
|
|
1366 | otherwise always forced to be at least one) and all the other fields of |
|
|
1367 | the stat buffer having unspecified contents. |
|
|
1368 | |
|
|
1369 | The path I<should> be absolute and I<must not> end in a slash. If it is |
|
|
1370 | relative and your working directory changes, the behaviour is undefined. |
|
|
1371 | |
|
|
1372 | Since there is no standard to do this, the portable implementation simply |
|
|
1373 | calls C<stat (2)> regularly on the path to see if it changed somehow. You |
|
|
1374 | can specify a recommended polling interval for this case. If you specify |
|
|
1375 | a polling interval of C<0> (highly recommended!) then a I<suitable, |
|
|
1376 | unspecified default> value will be used (which you can expect to be around |
|
|
1377 | five seconds, although this might change dynamically). Libev will also |
|
|
1378 | impose a minimum interval which is currently around C<0.1>, but thats |
|
|
1379 | usually overkill. |
|
|
1380 | |
|
|
1381 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
1382 | as even with OS-supported change notifications, this can be |
|
|
1383 | resource-intensive. |
|
|
1384 | |
|
|
1385 | At the time of this writing, only the Linux inotify interface is |
|
|
1386 | implemented (implementing kqueue support is left as an exercise for the |
|
|
1387 | reader). Inotify will be used to give hints only and should not change the |
|
|
1388 | semantics of C<ev_stat> watchers, which means that libev sometimes needs |
|
|
1389 | to fall back to regular polling again even with inotify, but changes are |
|
|
1390 | usually detected immediately, and if the file exists there will be no |
|
|
1391 | polling. |
|
|
1392 | |
|
|
1393 | =head3 Watcher-Specific Functions and Data Members |
|
|
1394 | |
|
|
1395 | =over 4 |
|
|
1396 | |
|
|
1397 | =item ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval) |
|
|
1398 | |
|
|
1399 | =item ev_stat_set (ev_stat *, const char *path, ev_tstamp interval) |
|
|
1400 | |
|
|
1401 | Configures the watcher to wait for status changes of the given |
|
|
1402 | C<path>. The C<interval> is a hint on how quickly a change is expected to |
|
|
1403 | be detected and should normally be specified as C<0> to let libev choose |
|
|
1404 | a suitable value. The memory pointed to by C<path> must point to the same |
|
|
1405 | path for as long as the watcher is active. |
|
|
1406 | |
|
|
1407 | The callback will be receive C<EV_STAT> when a change was detected, |
|
|
1408 | relative to the attributes at the time the watcher was started (or the |
|
|
1409 | last change was detected). |
|
|
1410 | |
|
|
1411 | =item ev_stat_stat (ev_stat *) |
|
|
1412 | |
|
|
1413 | Updates the stat buffer immediately with new values. If you change the |
|
|
1414 | watched path in your callback, you could call this fucntion to avoid |
|
|
1415 | detecting this change (while introducing a race condition). Can also be |
|
|
1416 | useful simply to find out the new values. |
|
|
1417 | |
|
|
1418 | =item ev_statdata attr [read-only] |
|
|
1419 | |
|
|
1420 | The most-recently detected attributes of the file. Although the type is of |
|
|
1421 | C<ev_statdata>, this is usually the (or one of the) C<struct stat> types |
|
|
1422 | suitable for your system. If the C<st_nlink> member is C<0>, then there |
|
|
1423 | was some error while C<stat>ing the file. |
|
|
1424 | |
|
|
1425 | =item ev_statdata prev [read-only] |
|
|
1426 | |
|
|
1427 | The previous attributes of the file. The callback gets invoked whenever |
|
|
1428 | C<prev> != C<attr>. |
|
|
1429 | |
|
|
1430 | =item ev_tstamp interval [read-only] |
|
|
1431 | |
|
|
1432 | The specified interval. |
|
|
1433 | |
|
|
1434 | =item const char *path [read-only] |
|
|
1435 | |
|
|
1436 | The filesystem path that is being watched. |
|
|
1437 | |
|
|
1438 | =back |
|
|
1439 | |
|
|
1440 | Example: Watch C</etc/passwd> for attribute changes. |
|
|
1441 | |
|
|
1442 | static void |
|
|
1443 | passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
|
|
1444 | { |
|
|
1445 | /* /etc/passwd changed in some way */ |
|
|
1446 | if (w->attr.st_nlink) |
|
|
1447 | { |
|
|
1448 | printf ("passwd current size %ld\n", (long)w->attr.st_size); |
|
|
1449 | printf ("passwd current atime %ld\n", (long)w->attr.st_mtime); |
|
|
1450 | printf ("passwd current mtime %ld\n", (long)w->attr.st_mtime); |
|
|
1451 | } |
|
|
1452 | else |
|
|
1453 | /* you shalt not abuse printf for puts */ |
|
|
1454 | puts ("wow, /etc/passwd is not there, expect problems. " |
|
|
1455 | "if this is windows, they already arrived\n"); |
|
|
1456 | } |
|
|
1457 | |
|
|
1458 | ... |
|
|
1459 | ev_stat passwd; |
|
|
1460 | |
|
|
1461 | ev_stat_init (&passwd, passwd_cb, "/etc/passwd"); |
|
|
1462 | ev_stat_start (loop, &passwd); |
|
|
1463 | |
|
|
1464 | |
1057 | =head2 C<ev_idle> - when you've got nothing better to do... |
1465 | =head2 C<ev_idle> - when you've got nothing better to do... |
1058 | |
1466 | |
1059 | Idle watchers trigger events when there are no other events are pending |
1467 | Idle watchers trigger events when no other events of the same or higher |
1060 | (prepare, check and other idle watchers do not count). That is, as long |
1468 | priority are pending (prepare, check and other idle watchers do not |
1061 | as your process is busy handling sockets or timeouts (or even signals, |
1469 | count). |
1062 | imagine) it will not be triggered. But when your process is idle all idle |
1470 | |
1063 | watchers are being called again and again, once per event loop iteration - |
1471 | That is, as long as your process is busy handling sockets or timeouts |
|
|
1472 | (or even signals, imagine) of the same or higher priority it will not be |
|
|
1473 | triggered. But when your process is idle (or only lower-priority watchers |
|
|
1474 | are pending), the idle watchers are being called once per event loop |
1064 | until stopped, that is, or your process receives more events and becomes |
1475 | iteration - until stopped, that is, or your process receives more events |
1065 | busy. |
1476 | and becomes busy again with higher priority stuff. |
1066 | |
1477 | |
1067 | The most noteworthy effect is that as long as any idle watchers are |
1478 | The most noteworthy effect is that as long as any idle watchers are |
1068 | active, the process will not block when waiting for new events. |
1479 | active, the process will not block when waiting for new events. |
1069 | |
1480 | |
1070 | Apart from keeping your process non-blocking (which is a useful |
1481 | Apart from keeping your process non-blocking (which is a useful |
1071 | effect on its own sometimes), idle watchers are a good place to do |
1482 | effect on its own sometimes), idle watchers are a good place to do |
1072 | "pseudo-background processing", or delay processing stuff to after the |
1483 | "pseudo-background processing", or delay processing stuff to after the |
1073 | event loop has handled all outstanding events. |
1484 | event loop has handled all outstanding events. |
1074 | |
1485 | |
|
|
1486 | =head3 Watcher-Specific Functions and Data Members |
|
|
1487 | |
1075 | =over 4 |
1488 | =over 4 |
1076 | |
1489 | |
1077 | =item ev_idle_init (ev_signal *, callback) |
1490 | =item ev_idle_init (ev_signal *, callback) |
1078 | |
1491 | |
1079 | Initialises and configures the idle watcher - it has no parameters of any |
1492 | Initialises and configures the idle watcher - it has no parameters of any |
1080 | kind. There is a C<ev_idle_set> macro, but using it is utterly pointless, |
1493 | kind. There is a C<ev_idle_set> macro, but using it is utterly pointless, |
1081 | believe me. |
1494 | believe me. |
1082 | |
1495 | |
1083 | =back |
1496 | =back |
1084 | |
1497 | |
1085 | Example: dynamically allocate an C<ev_idle>, start it, and in the |
1498 | Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the |
1086 | callback, free it. Alos, use no error checking, as usual. |
1499 | callback, free it. Also, use no error checking, as usual. |
1087 | |
1500 | |
1088 | static void |
1501 | static void |
1089 | idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1502 | idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents) |
1090 | { |
1503 | { |
1091 | free (w); |
1504 | free (w); |
… | |
… | |
1136 | with priority higher than or equal to the event loop and one coroutine |
1549 | with priority higher than or equal to the event loop and one coroutine |
1137 | of lower priority, but only once, using idle watchers to keep the event |
1550 | of lower priority, but only once, using idle watchers to keep the event |
1138 | loop from blocking if lower-priority coroutines are active, thus mapping |
1551 | loop from blocking if lower-priority coroutines are active, thus mapping |
1139 | low-priority coroutines to idle/background tasks). |
1552 | low-priority coroutines to idle/background tasks). |
1140 | |
1553 | |
|
|
1554 | It is recommended to give C<ev_check> watchers highest (C<EV_MAXPRI>) |
|
|
1555 | priority, to ensure that they are being run before any other watchers |
|
|
1556 | after the poll. Also, C<ev_check> watchers (and C<ev_prepare> watchers, |
|
|
1557 | too) should not activate ("feed") events into libev. While libev fully |
|
|
1558 | supports this, they will be called before other C<ev_check> watchers did |
|
|
1559 | their job. As C<ev_check> watchers are often used to embed other event |
|
|
1560 | loops those other event loops might be in an unusable state until their |
|
|
1561 | C<ev_check> watcher ran (always remind yourself to coexist peacefully with |
|
|
1562 | others). |
|
|
1563 | |
|
|
1564 | =head3 Watcher-Specific Functions and Data Members |
|
|
1565 | |
1141 | =over 4 |
1566 | =over 4 |
1142 | |
1567 | |
1143 | =item ev_prepare_init (ev_prepare *, callback) |
1568 | =item ev_prepare_init (ev_prepare *, callback) |
1144 | |
1569 | |
1145 | =item ev_check_init (ev_check *, callback) |
1570 | =item ev_check_init (ev_check *, callback) |
… | |
… | |
1148 | parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set> |
1573 | parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set> |
1149 | macros, but using them is utterly, utterly and completely pointless. |
1574 | macros, but using them is utterly, utterly and completely pointless. |
1150 | |
1575 | |
1151 | =back |
1576 | =back |
1152 | |
1577 | |
1153 | Example: To include a library such as adns, you would add IO watchers |
1578 | There are a number of principal ways to embed other event loops or modules |
1154 | and a timeout watcher in a prepare handler, as required by libadns, and |
1579 | into libev. Here are some ideas on how to include libadns into libev |
|
|
1580 | (there is a Perl module named C<EV::ADNS> that does this, which you could |
|
|
1581 | use for an actually working example. Another Perl module named C<EV::Glib> |
|
|
1582 | embeds a Glib main context into libev, and finally, C<Glib::EV> embeds EV |
|
|
1583 | into the Glib event loop). |
|
|
1584 | |
|
|
1585 | Method 1: Add IO watchers and a timeout watcher in a prepare handler, |
1155 | in a check watcher, destroy them and call into libadns. What follows is |
1586 | and in a check watcher, destroy them and call into libadns. What follows |
1156 | pseudo-code only of course: |
1587 | is pseudo-code only of course. This requires you to either use a low |
|
|
1588 | priority for the check watcher or use C<ev_clear_pending> explicitly, as |
|
|
1589 | the callbacks for the IO/timeout watchers might not have been called yet. |
1157 | |
1590 | |
1158 | static ev_io iow [nfd]; |
1591 | static ev_io iow [nfd]; |
1159 | static ev_timer tw; |
1592 | static ev_timer tw; |
1160 | |
1593 | |
1161 | static void |
1594 | static void |
1162 | io_cb (ev_loop *loop, ev_io *w, int revents) |
1595 | io_cb (ev_loop *loop, ev_io *w, int revents) |
1163 | { |
1596 | { |
1164 | // set the relevant poll flags |
|
|
1165 | struct pollfd *fd = (struct pollfd *)w->data; |
|
|
1166 | if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1167 | if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1168 | } |
1597 | } |
1169 | |
1598 | |
1170 | // create io watchers for each fd and a timer before blocking |
1599 | // create io watchers for each fd and a timer before blocking |
1171 | static void |
1600 | static void |
1172 | adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1601 | adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1173 | { |
1602 | { |
1174 | int timeout = 3600000;truct pollfd fds [nfd]; |
1603 | int timeout = 3600000; |
|
|
1604 | struct pollfd fds [nfd]; |
1175 | // actual code will need to loop here and realloc etc. |
1605 | // actual code will need to loop here and realloc etc. |
1176 | adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1606 | adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1177 | |
1607 | |
1178 | /* the callback is illegal, but won't be called as we stop during check */ |
1608 | /* the callback is illegal, but won't be called as we stop during check */ |
1179 | ev_timer_init (&tw, 0, timeout * 1e-3); |
1609 | ev_timer_init (&tw, 0, timeout * 1e-3); |
1180 | ev_timer_start (loop, &tw); |
1610 | ev_timer_start (loop, &tw); |
1181 | |
1611 | |
1182 | // create on ev_io per pollfd |
1612 | // create one ev_io per pollfd |
1183 | for (int i = 0; i < nfd; ++i) |
1613 | for (int i = 0; i < nfd; ++i) |
1184 | { |
1614 | { |
1185 | ev_io_init (iow + i, io_cb, fds [i].fd, |
1615 | ev_io_init (iow + i, io_cb, fds [i].fd, |
1186 | ((fds [i].events & POLLIN ? EV_READ : 0) |
1616 | ((fds [i].events & POLLIN ? EV_READ : 0) |
1187 | | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1617 | | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1188 | |
1618 | |
1189 | fds [i].revents = 0; |
1619 | fds [i].revents = 0; |
1190 | iow [i].data = fds + i; |
|
|
1191 | ev_io_start (loop, iow + i); |
1620 | ev_io_start (loop, iow + i); |
1192 | } |
1621 | } |
1193 | } |
1622 | } |
1194 | |
1623 | |
1195 | // stop all watchers after blocking |
1624 | // stop all watchers after blocking |
… | |
… | |
1197 | adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1626 | adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1198 | { |
1627 | { |
1199 | ev_timer_stop (loop, &tw); |
1628 | ev_timer_stop (loop, &tw); |
1200 | |
1629 | |
1201 | for (int i = 0; i < nfd; ++i) |
1630 | for (int i = 0; i < nfd; ++i) |
|
|
1631 | { |
|
|
1632 | // set the relevant poll flags |
|
|
1633 | // could also call adns_processreadable etc. here |
|
|
1634 | struct pollfd *fd = fds + i; |
|
|
1635 | int revents = ev_clear_pending (iow + i); |
|
|
1636 | if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1637 | if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1638 | |
|
|
1639 | // now stop the watcher |
1202 | ev_io_stop (loop, iow + i); |
1640 | ev_io_stop (loop, iow + i); |
|
|
1641 | } |
1203 | |
1642 | |
1204 | adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
1643 | adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
|
|
1644 | } |
|
|
1645 | |
|
|
1646 | Method 2: This would be just like method 1, but you run C<adns_afterpoll> |
|
|
1647 | in the prepare watcher and would dispose of the check watcher. |
|
|
1648 | |
|
|
1649 | Method 3: If the module to be embedded supports explicit event |
|
|
1650 | notification (adns does), you can also make use of the actual watcher |
|
|
1651 | callbacks, and only destroy/create the watchers in the prepare watcher. |
|
|
1652 | |
|
|
1653 | static void |
|
|
1654 | timer_cb (EV_P_ ev_timer *w, int revents) |
|
|
1655 | { |
|
|
1656 | adns_state ads = (adns_state)w->data; |
|
|
1657 | update_now (EV_A); |
|
|
1658 | |
|
|
1659 | adns_processtimeouts (ads, &tv_now); |
|
|
1660 | } |
|
|
1661 | |
|
|
1662 | static void |
|
|
1663 | io_cb (EV_P_ ev_io *w, int revents) |
|
|
1664 | { |
|
|
1665 | adns_state ads = (adns_state)w->data; |
|
|
1666 | update_now (EV_A); |
|
|
1667 | |
|
|
1668 | if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now); |
|
|
1669 | if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now); |
|
|
1670 | } |
|
|
1671 | |
|
|
1672 | // do not ever call adns_afterpoll |
|
|
1673 | |
|
|
1674 | Method 4: Do not use a prepare or check watcher because the module you |
|
|
1675 | want to embed is too inflexible to support it. Instead, youc na override |
|
|
1676 | their poll function. The drawback with this solution is that the main |
|
|
1677 | loop is now no longer controllable by EV. The C<Glib::EV> module does |
|
|
1678 | this. |
|
|
1679 | |
|
|
1680 | static gint |
|
|
1681 | event_poll_func (GPollFD *fds, guint nfds, gint timeout) |
|
|
1682 | { |
|
|
1683 | int got_events = 0; |
|
|
1684 | |
|
|
1685 | for (n = 0; n < nfds; ++n) |
|
|
1686 | // create/start io watcher that sets the relevant bits in fds[n] and increment got_events |
|
|
1687 | |
|
|
1688 | if (timeout >= 0) |
|
|
1689 | // create/start timer |
|
|
1690 | |
|
|
1691 | // poll |
|
|
1692 | ev_loop (EV_A_ 0); |
|
|
1693 | |
|
|
1694 | // stop timer again |
|
|
1695 | if (timeout >= 0) |
|
|
1696 | ev_timer_stop (EV_A_ &to); |
|
|
1697 | |
|
|
1698 | // stop io watchers again - their callbacks should have set |
|
|
1699 | for (n = 0; n < nfds; ++n) |
|
|
1700 | ev_io_stop (EV_A_ iow [n]); |
|
|
1701 | |
|
|
1702 | return got_events; |
1205 | } |
1703 | } |
1206 | |
1704 | |
1207 | |
1705 | |
1208 | =head2 C<ev_embed> - when one backend isn't enough... |
1706 | =head2 C<ev_embed> - when one backend isn't enough... |
1209 | |
1707 | |
… | |
… | |
1273 | ev_embed_start (loop_hi, &embed); |
1771 | ev_embed_start (loop_hi, &embed); |
1274 | } |
1772 | } |
1275 | else |
1773 | else |
1276 | loop_lo = loop_hi; |
1774 | loop_lo = loop_hi; |
1277 | |
1775 | |
|
|
1776 | =head3 Watcher-Specific Functions and Data Members |
|
|
1777 | |
1278 | =over 4 |
1778 | =over 4 |
1279 | |
1779 | |
1280 | =item ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop) |
1780 | =item ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop) |
1281 | |
1781 | |
1282 | =item ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop) |
1782 | =item ev_embed_set (ev_embed *, callback, struct ev_loop *embedded_loop) |
… | |
… | |
1291 | |
1791 | |
1292 | Make a single, non-blocking sweep over the embedded loop. This works |
1792 | Make a single, non-blocking sweep over the embedded loop. This works |
1293 | similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most |
1793 | similarly to C<ev_loop (embedded_loop, EVLOOP_NONBLOCK)>, but in the most |
1294 | apropriate way for embedded loops. |
1794 | apropriate way for embedded loops. |
1295 | |
1795 | |
|
|
1796 | =item struct ev_loop *loop [read-only] |
|
|
1797 | |
|
|
1798 | The embedded event loop. |
|
|
1799 | |
|
|
1800 | =back |
|
|
1801 | |
|
|
1802 | |
|
|
1803 | =head2 C<ev_fork> - the audacity to resume the event loop after a fork |
|
|
1804 | |
|
|
1805 | Fork watchers are called when a C<fork ()> was detected (usually because |
|
|
1806 | whoever is a good citizen cared to tell libev about it by calling |
|
|
1807 | C<ev_default_fork> or C<ev_loop_fork>). The invocation is done before the |
|
|
1808 | event loop blocks next and before C<ev_check> watchers are being called, |
|
|
1809 | and only in the child after the fork. If whoever good citizen calling |
|
|
1810 | C<ev_default_fork> cheats and calls it in the wrong process, the fork |
|
|
1811 | handlers will be invoked, too, of course. |
|
|
1812 | |
|
|
1813 | =head3 Watcher-Specific Functions and Data Members |
|
|
1814 | |
|
|
1815 | =over 4 |
|
|
1816 | |
|
|
1817 | =item ev_fork_init (ev_signal *, callback) |
|
|
1818 | |
|
|
1819 | Initialises and configures the fork watcher - it has no parameters of any |
|
|
1820 | kind. There is a C<ev_fork_set> macro, but using it is utterly pointless, |
|
|
1821 | believe me. |
|
|
1822 | |
1296 | =back |
1823 | =back |
1297 | |
1824 | |
1298 | |
1825 | |
1299 | =head1 OTHER FUNCTIONS |
1826 | =head1 OTHER FUNCTIONS |
1300 | |
1827 | |
… | |
… | |
1388 | |
1915 | |
1389 | To use it, |
1916 | To use it, |
1390 | |
1917 | |
1391 | #include <ev++.h> |
1918 | #include <ev++.h> |
1392 | |
1919 | |
1393 | (it is not installed by default). This automatically includes F<ev.h> |
1920 | This automatically includes F<ev.h> and puts all of its definitions (many |
1394 | and puts all of its definitions (many of them macros) into the global |
1921 | of them macros) into the global namespace. All C++ specific things are |
1395 | namespace. All C++ specific things are put into the C<ev> namespace. |
1922 | put into the C<ev> namespace. It should support all the same embedding |
|
|
1923 | options as F<ev.h>, most notably C<EV_MULTIPLICITY>. |
1396 | |
1924 | |
1397 | It should support all the same embedding options as F<ev.h>, most notably |
1925 | Care has been taken to keep the overhead low. The only data member the C++ |
1398 | C<EV_MULTIPLICITY>. |
1926 | classes add (compared to plain C-style watchers) is the event loop pointer |
|
|
1927 | that the watcher is associated with (or no additional members at all if |
|
|
1928 | you disable C<EV_MULTIPLICITY> when embedding libev). |
|
|
1929 | |
|
|
1930 | Currently, functions, and static and non-static member functions can be |
|
|
1931 | used as callbacks. Other types should be easy to add as long as they only |
|
|
1932 | need one additional pointer for context. If you need support for other |
|
|
1933 | types of functors please contact the author (preferably after implementing |
|
|
1934 | it). |
1399 | |
1935 | |
1400 | Here is a list of things available in the C<ev> namespace: |
1936 | Here is a list of things available in the C<ev> namespace: |
1401 | |
1937 | |
1402 | =over 4 |
1938 | =over 4 |
1403 | |
1939 | |
… | |
… | |
1419 | |
1955 | |
1420 | All of those classes have these methods: |
1956 | All of those classes have these methods: |
1421 | |
1957 | |
1422 | =over 4 |
1958 | =over 4 |
1423 | |
1959 | |
1424 | =item ev::TYPE::TYPE (object *, object::method *) |
1960 | =item ev::TYPE::TYPE () |
1425 | |
1961 | |
1426 | =item ev::TYPE::TYPE (object *, object::method *, struct ev_loop *) |
1962 | =item ev::TYPE::TYPE (struct ev_loop *) |
1427 | |
1963 | |
1428 | =item ev::TYPE::~TYPE |
1964 | =item ev::TYPE::~TYPE |
1429 | |
1965 | |
1430 | The constructor takes a pointer to an object and a method pointer to |
1966 | The constructor (optionally) takes an event loop to associate the watcher |
1431 | the event handler callback to call in this class. The constructor calls |
1967 | with. If it is omitted, it will use C<EV_DEFAULT>. |
1432 | C<ev_init> for you, which means you have to call the C<set> method |
1968 | |
1433 | before starting it. If you do not specify a loop then the constructor |
1969 | The constructor calls C<ev_init> for you, which means you have to call the |
1434 | automatically associates the default loop with this watcher. |
1970 | C<set> method before starting it. |
|
|
1971 | |
|
|
1972 | It will not set a callback, however: You have to call the templated C<set> |
|
|
1973 | method to set a callback before you can start the watcher. |
|
|
1974 | |
|
|
1975 | (The reason why you have to use a method is a limitation in C++ which does |
|
|
1976 | not allow explicit template arguments for constructors). |
1435 | |
1977 | |
1436 | The destructor automatically stops the watcher if it is active. |
1978 | The destructor automatically stops the watcher if it is active. |
|
|
1979 | |
|
|
1980 | =item w->set<class, &class::method> (object *) |
|
|
1981 | |
|
|
1982 | This method sets the callback method to call. The method has to have a |
|
|
1983 | signature of C<void (*)(ev_TYPE &, int)>, it receives the watcher as |
|
|
1984 | first argument and the C<revents> as second. The object must be given as |
|
|
1985 | parameter and is stored in the C<data> member of the watcher. |
|
|
1986 | |
|
|
1987 | This method synthesizes efficient thunking code to call your method from |
|
|
1988 | the C callback that libev requires. If your compiler can inline your |
|
|
1989 | callback (i.e. it is visible to it at the place of the C<set> call and |
|
|
1990 | your compiler is good :), then the method will be fully inlined into the |
|
|
1991 | thunking function, making it as fast as a direct C callback. |
|
|
1992 | |
|
|
1993 | Example: simple class declaration and watcher initialisation |
|
|
1994 | |
|
|
1995 | struct myclass |
|
|
1996 | { |
|
|
1997 | void io_cb (ev::io &w, int revents) { } |
|
|
1998 | } |
|
|
1999 | |
|
|
2000 | myclass obj; |
|
|
2001 | ev::io iow; |
|
|
2002 | iow.set <myclass, &myclass::io_cb> (&obj); |
|
|
2003 | |
|
|
2004 | =item w->set<function> (void *data = 0) |
|
|
2005 | |
|
|
2006 | Also sets a callback, but uses a static method or plain function as |
|
|
2007 | callback. The optional C<data> argument will be stored in the watcher's |
|
|
2008 | C<data> member and is free for you to use. |
|
|
2009 | |
|
|
2010 | The prototype of the C<function> must be C<void (*)(ev::TYPE &w, int)>. |
|
|
2011 | |
|
|
2012 | See the method-C<set> above for more details. |
|
|
2013 | |
|
|
2014 | Example: |
|
|
2015 | |
|
|
2016 | static void io_cb (ev::io &w, int revents) { } |
|
|
2017 | iow.set <io_cb> (); |
1437 | |
2018 | |
1438 | =item w->set (struct ev_loop *) |
2019 | =item w->set (struct ev_loop *) |
1439 | |
2020 | |
1440 | Associates a different C<struct ev_loop> with this watcher. You can only |
2021 | Associates a different C<struct ev_loop> with this watcher. You can only |
1441 | do this when the watcher is inactive (and not pending either). |
2022 | do this when the watcher is inactive (and not pending either). |
1442 | |
2023 | |
1443 | =item w->set ([args]) |
2024 | =item w->set ([args]) |
1444 | |
2025 | |
1445 | Basically the same as C<ev_TYPE_set>, with the same args. Must be |
2026 | Basically the same as C<ev_TYPE_set>, with the same args. Must be |
1446 | called at least once. Unlike the C counterpart, an active watcher gets |
2027 | called at least once. Unlike the C counterpart, an active watcher gets |
1447 | automatically stopped and restarted. |
2028 | automatically stopped and restarted when reconfiguring it with this |
|
|
2029 | method. |
1448 | |
2030 | |
1449 | =item w->start () |
2031 | =item w->start () |
1450 | |
2032 | |
1451 | Starts the watcher. Note that there is no C<loop> argument as the |
2033 | Starts the watcher. Note that there is no C<loop> argument, as the |
1452 | constructor already takes the loop. |
2034 | constructor already stores the event loop. |
1453 | |
2035 | |
1454 | =item w->stop () |
2036 | =item w->stop () |
1455 | |
2037 | |
1456 | Stops the watcher if it is active. Again, no C<loop> argument. |
2038 | Stops the watcher if it is active. Again, no C<loop> argument. |
1457 | |
2039 | |
1458 | =item w->again () C<ev::timer>, C<ev::periodic> only |
2040 | =item w->again () (C<ev::timer>, C<ev::periodic> only) |
1459 | |
2041 | |
1460 | For C<ev::timer> and C<ev::periodic>, this invokes the corresponding |
2042 | For C<ev::timer> and C<ev::periodic>, this invokes the corresponding |
1461 | C<ev_TYPE_again> function. |
2043 | C<ev_TYPE_again> function. |
1462 | |
2044 | |
1463 | =item w->sweep () C<ev::embed> only |
2045 | =item w->sweep () (C<ev::embed> only) |
1464 | |
2046 | |
1465 | Invokes C<ev_embed_sweep>. |
2047 | Invokes C<ev_embed_sweep>. |
|
|
2048 | |
|
|
2049 | =item w->update () (C<ev::stat> only) |
|
|
2050 | |
|
|
2051 | Invokes C<ev_stat_stat>. |
1466 | |
2052 | |
1467 | =back |
2053 | =back |
1468 | |
2054 | |
1469 | =back |
2055 | =back |
1470 | |
2056 | |
… | |
… | |
1478 | |
2064 | |
1479 | myclass (); |
2065 | myclass (); |
1480 | } |
2066 | } |
1481 | |
2067 | |
1482 | myclass::myclass (int fd) |
2068 | myclass::myclass (int fd) |
1483 | : io (this, &myclass::io_cb), |
|
|
1484 | idle (this, &myclass::idle_cb) |
|
|
1485 | { |
2069 | { |
|
|
2070 | io .set <myclass, &myclass::io_cb > (this); |
|
|
2071 | idle.set <myclass, &myclass::idle_cb> (this); |
|
|
2072 | |
1486 | io.start (fd, ev::READ); |
2073 | io.start (fd, ev::READ); |
1487 | } |
2074 | } |
|
|
2075 | |
|
|
2076 | |
|
|
2077 | =head1 MACRO MAGIC |
|
|
2078 | |
|
|
2079 | Libev can be compiled with a variety of options, the most fundamantal |
|
|
2080 | of which is C<EV_MULTIPLICITY>. This option determines whether (most) |
|
|
2081 | functions and callbacks have an initial C<struct ev_loop *> argument. |
|
|
2082 | |
|
|
2083 | To make it easier to write programs that cope with either variant, the |
|
|
2084 | following macros are defined: |
|
|
2085 | |
|
|
2086 | =over 4 |
|
|
2087 | |
|
|
2088 | =item C<EV_A>, C<EV_A_> |
|
|
2089 | |
|
|
2090 | This provides the loop I<argument> for functions, if one is required ("ev |
|
|
2091 | loop argument"). The C<EV_A> form is used when this is the sole argument, |
|
|
2092 | C<EV_A_> is used when other arguments are following. Example: |
|
|
2093 | |
|
|
2094 | ev_unref (EV_A); |
|
|
2095 | ev_timer_add (EV_A_ watcher); |
|
|
2096 | ev_loop (EV_A_ 0); |
|
|
2097 | |
|
|
2098 | It assumes the variable C<loop> of type C<struct ev_loop *> is in scope, |
|
|
2099 | which is often provided by the following macro. |
|
|
2100 | |
|
|
2101 | =item C<EV_P>, C<EV_P_> |
|
|
2102 | |
|
|
2103 | This provides the loop I<parameter> for functions, if one is required ("ev |
|
|
2104 | loop parameter"). The C<EV_P> form is used when this is the sole parameter, |
|
|
2105 | C<EV_P_> is used when other parameters are following. Example: |
|
|
2106 | |
|
|
2107 | // this is how ev_unref is being declared |
|
|
2108 | static void ev_unref (EV_P); |
|
|
2109 | |
|
|
2110 | // this is how you can declare your typical callback |
|
|
2111 | static void cb (EV_P_ ev_timer *w, int revents) |
|
|
2112 | |
|
|
2113 | It declares a parameter C<loop> of type C<struct ev_loop *>, quite |
|
|
2114 | suitable for use with C<EV_A>. |
|
|
2115 | |
|
|
2116 | =item C<EV_DEFAULT>, C<EV_DEFAULT_> |
|
|
2117 | |
|
|
2118 | Similar to the other two macros, this gives you the value of the default |
|
|
2119 | loop, if multiple loops are supported ("ev loop default"). |
|
|
2120 | |
|
|
2121 | =back |
|
|
2122 | |
|
|
2123 | Example: Declare and initialise a check watcher, utilising the above |
|
|
2124 | macros so it will work regardless of whether multiple loops are supported |
|
|
2125 | or not. |
|
|
2126 | |
|
|
2127 | static void |
|
|
2128 | check_cb (EV_P_ ev_timer *w, int revents) |
|
|
2129 | { |
|
|
2130 | ev_check_stop (EV_A_ w); |
|
|
2131 | } |
|
|
2132 | |
|
|
2133 | ev_check check; |
|
|
2134 | ev_check_init (&check, check_cb); |
|
|
2135 | ev_check_start (EV_DEFAULT_ &check); |
|
|
2136 | ev_loop (EV_DEFAULT_ 0); |
1488 | |
2137 | |
1489 | =head1 EMBEDDING |
2138 | =head1 EMBEDDING |
1490 | |
2139 | |
1491 | Libev can (and often is) directly embedded into host |
2140 | Libev can (and often is) directly embedded into host |
1492 | applications. Examples of applications that embed it include the Deliantra |
2141 | applications. Examples of applications that embed it include the Deliantra |
… | |
… | |
1532 | ev_vars.h |
2181 | ev_vars.h |
1533 | ev_wrap.h |
2182 | ev_wrap.h |
1534 | |
2183 | |
1535 | ev_win32.c required on win32 platforms only |
2184 | ev_win32.c required on win32 platforms only |
1536 | |
2185 | |
1537 | ev_select.c only when select backend is enabled (which is by default) |
2186 | ev_select.c only when select backend is enabled (which is enabled by default) |
1538 | ev_poll.c only when poll backend is enabled (disabled by default) |
2187 | ev_poll.c only when poll backend is enabled (disabled by default) |
1539 | ev_epoll.c only when the epoll backend is enabled (disabled by default) |
2188 | ev_epoll.c only when the epoll backend is enabled (disabled by default) |
1540 | ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
2189 | ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
1541 | ev_port.c only when the solaris port backend is enabled (disabled by default) |
2190 | ev_port.c only when the solaris port backend is enabled (disabled by default) |
1542 | |
2191 | |
… | |
… | |
1667 | |
2316 | |
1668 | =item EV_USE_DEVPOLL |
2317 | =item EV_USE_DEVPOLL |
1669 | |
2318 | |
1670 | reserved for future expansion, works like the USE symbols above. |
2319 | reserved for future expansion, works like the USE symbols above. |
1671 | |
2320 | |
|
|
2321 | =item EV_USE_INOTIFY |
|
|
2322 | |
|
|
2323 | If defined to be C<1>, libev will compile in support for the Linux inotify |
|
|
2324 | interface to speed up C<ev_stat> watchers. Its actual availability will |
|
|
2325 | be detected at runtime. |
|
|
2326 | |
1672 | =item EV_H |
2327 | =item EV_H |
1673 | |
2328 | |
1674 | The name of the F<ev.h> header file used to include it. The default if |
2329 | The name of the F<ev.h> header file used to include it. The default if |
1675 | undefined is C<< <ev.h> >> in F<event.h> and C<"ev.h"> in F<ev.c>. This |
2330 | undefined is C<< <ev.h> >> in F<event.h> and C<"ev.h"> in F<ev.c>. This |
1676 | can be used to virtually rename the F<ev.h> header file in case of conflicts. |
2331 | can be used to virtually rename the F<ev.h> header file in case of conflicts. |
… | |
… | |
1699 | will have the C<struct ev_loop *> as first argument, and you can create |
2354 | will have the C<struct ev_loop *> as first argument, and you can create |
1700 | additional independent event loops. Otherwise there will be no support |
2355 | additional independent event loops. Otherwise there will be no support |
1701 | for multiple event loops and there is no first event loop pointer |
2356 | for multiple event loops and there is no first event loop pointer |
1702 | argument. Instead, all functions act on the single default loop. |
2357 | argument. Instead, all functions act on the single default loop. |
1703 | |
2358 | |
|
|
2359 | =item EV_MINPRI |
|
|
2360 | |
|
|
2361 | =item EV_MAXPRI |
|
|
2362 | |
|
|
2363 | The range of allowed priorities. C<EV_MINPRI> must be smaller or equal to |
|
|
2364 | C<EV_MAXPRI>, but otherwise there are no non-obvious limitations. You can |
|
|
2365 | provide for more priorities by overriding those symbols (usually defined |
|
|
2366 | to be C<-2> and C<2>, respectively). |
|
|
2367 | |
|
|
2368 | When doing priority-based operations, libev usually has to linearly search |
|
|
2369 | all the priorities, so having many of them (hundreds) uses a lot of space |
|
|
2370 | and time, so using the defaults of five priorities (-2 .. +2) is usually |
|
|
2371 | fine. |
|
|
2372 | |
|
|
2373 | If your embedding app does not need any priorities, defining these both to |
|
|
2374 | C<0> will save some memory and cpu. |
|
|
2375 | |
1704 | =item EV_PERIODICS |
2376 | =item EV_PERIODIC_ENABLE |
1705 | |
2377 | |
1706 | If undefined or defined to be C<1>, then periodic timers are supported, |
2378 | If undefined or defined to be C<1>, then periodic timers are supported. If |
1707 | otherwise not. This saves a few kb of code. |
2379 | defined to be C<0>, then they are not. Disabling them saves a few kB of |
|
|
2380 | code. |
|
|
2381 | |
|
|
2382 | =item EV_IDLE_ENABLE |
|
|
2383 | |
|
|
2384 | If undefined or defined to be C<1>, then idle watchers are supported. If |
|
|
2385 | defined to be C<0>, then they are not. Disabling them saves a few kB of |
|
|
2386 | code. |
|
|
2387 | |
|
|
2388 | =item EV_EMBED_ENABLE |
|
|
2389 | |
|
|
2390 | If undefined or defined to be C<1>, then embed watchers are supported. If |
|
|
2391 | defined to be C<0>, then they are not. |
|
|
2392 | |
|
|
2393 | =item EV_STAT_ENABLE |
|
|
2394 | |
|
|
2395 | If undefined or defined to be C<1>, then stat watchers are supported. If |
|
|
2396 | defined to be C<0>, then they are not. |
|
|
2397 | |
|
|
2398 | =item EV_FORK_ENABLE |
|
|
2399 | |
|
|
2400 | If undefined or defined to be C<1>, then fork watchers are supported. If |
|
|
2401 | defined to be C<0>, then they are not. |
|
|
2402 | |
|
|
2403 | =item EV_MINIMAL |
|
|
2404 | |
|
|
2405 | If you need to shave off some kilobytes of code at the expense of some |
|
|
2406 | speed, define this symbol to C<1>. Currently only used for gcc to override |
|
|
2407 | some inlining decisions, saves roughly 30% codesize of amd64. |
|
|
2408 | |
|
|
2409 | =item EV_PID_HASHSIZE |
|
|
2410 | |
|
|
2411 | C<ev_child> watchers use a small hash table to distribute workload by |
|
|
2412 | pid. The default size is C<16> (or C<1> with C<EV_MINIMAL>), usually more |
|
|
2413 | than enough. If you need to manage thousands of children you might want to |
|
|
2414 | increase this value (I<must> be a power of two). |
|
|
2415 | |
|
|
2416 | =item EV_INOTIFY_HASHSIZE |
|
|
2417 | |
|
|
2418 | C<ev_staz> watchers use a small hash table to distribute workload by |
|
|
2419 | inotify watch id. The default size is C<16> (or C<1> with C<EV_MINIMAL>), |
|
|
2420 | usually more than enough. If you need to manage thousands of C<ev_stat> |
|
|
2421 | watchers you might want to increase this value (I<must> be a power of |
|
|
2422 | two). |
1708 | |
2423 | |
1709 | =item EV_COMMON |
2424 | =item EV_COMMON |
1710 | |
2425 | |
1711 | By default, all watchers have a C<void *data> member. By redefining |
2426 | By default, all watchers have a C<void *data> member. By redefining |
1712 | this macro to a something else you can include more and other types of |
2427 | this macro to a something else you can include more and other types of |
… | |
… | |
1741 | interface) and F<EV.xs> (implementation) files. Only the F<EV.xs> file |
2456 | interface) and F<EV.xs> (implementation) files. Only the F<EV.xs> file |
1742 | will be compiled. It is pretty complex because it provides its own header |
2457 | will be compiled. It is pretty complex because it provides its own header |
1743 | file. |
2458 | file. |
1744 | |
2459 | |
1745 | The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file |
2460 | The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file |
1746 | that everybody includes and which overrides some autoconf choices: |
2461 | that everybody includes and which overrides some configure choices: |
1747 | |
2462 | |
|
|
2463 | #define EV_MINIMAL 1 |
1748 | #define EV_USE_POLL 0 |
2464 | #define EV_USE_POLL 0 |
1749 | #define EV_MULTIPLICITY 0 |
2465 | #define EV_MULTIPLICITY 0 |
1750 | #define EV_PERIODICS 0 |
2466 | #define EV_PERIODIC_ENABLE 0 |
|
|
2467 | #define EV_STAT_ENABLE 0 |
|
|
2468 | #define EV_FORK_ENABLE 0 |
1751 | #define EV_CONFIG_H <config.h> |
2469 | #define EV_CONFIG_H <config.h> |
|
|
2470 | #define EV_MINPRI 0 |
|
|
2471 | #define EV_MAXPRI 0 |
1752 | |
2472 | |
1753 | #include "ev++.h" |
2473 | #include "ev++.h" |
1754 | |
2474 | |
1755 | And a F<ev_cpp.C> implementation file that contains libev proper and is compiled: |
2475 | And a F<ev_cpp.C> implementation file that contains libev proper and is compiled: |
1756 | |
2476 | |
1757 | #include "ev_cpp.h" |
2477 | #include "ev_cpp.h" |
1758 | #include "ev.c" |
2478 | #include "ev.c" |
1759 | |
2479 | |
|
|
2480 | |
|
|
2481 | =head1 COMPLEXITIES |
|
|
2482 | |
|
|
2483 | In this section the complexities of (many of) the algorithms used inside |
|
|
2484 | libev will be explained. For complexity discussions about backends see the |
|
|
2485 | documentation for C<ev_default_init>. |
|
|
2486 | |
|
|
2487 | All of the following are about amortised time: If an array needs to be |
|
|
2488 | extended, libev needs to realloc and move the whole array, but this |
|
|
2489 | happens asymptotically never with higher number of elements, so O(1) might |
|
|
2490 | mean it might do a lengthy realloc operation in rare cases, but on average |
|
|
2491 | it is much faster and asymptotically approaches constant time. |
|
|
2492 | |
|
|
2493 | =over 4 |
|
|
2494 | |
|
|
2495 | =item Starting and stopping timer/periodic watchers: O(log skipped_other_timers) |
|
|
2496 | |
|
|
2497 | This means that, when you have a watcher that triggers in one hour and |
|
|
2498 | there are 100 watchers that would trigger before that then inserting will |
|
|
2499 | have to skip those 100 watchers. |
|
|
2500 | |
|
|
2501 | =item Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers) |
|
|
2502 | |
|
|
2503 | That means that for changing a timer costs less than removing/adding them |
|
|
2504 | as only the relative motion in the event queue has to be paid for. |
|
|
2505 | |
|
|
2506 | =item Starting io/check/prepare/idle/signal/child watchers: O(1) |
|
|
2507 | |
|
|
2508 | These just add the watcher into an array or at the head of a list. |
|
|
2509 | =item Stopping check/prepare/idle watchers: O(1) |
|
|
2510 | |
|
|
2511 | =item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE)) |
|
|
2512 | |
|
|
2513 | These watchers are stored in lists then need to be walked to find the |
|
|
2514 | correct watcher to remove. The lists are usually short (you don't usually |
|
|
2515 | have many watchers waiting for the same fd or signal). |
|
|
2516 | |
|
|
2517 | =item Finding the next timer per loop iteration: O(1) |
|
|
2518 | |
|
|
2519 | =item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd) |
|
|
2520 | |
|
|
2521 | A change means an I/O watcher gets started or stopped, which requires |
|
|
2522 | libev to recalculate its status (and possibly tell the kernel). |
|
|
2523 | |
|
|
2524 | =item Activating one watcher: O(1) |
|
|
2525 | |
|
|
2526 | =item Priority handling: O(number_of_priorities) |
|
|
2527 | |
|
|
2528 | Priorities are implemented by allocating some space for each |
|
|
2529 | priority. When doing priority-based operations, libev usually has to |
|
|
2530 | linearly search all the priorities. |
|
|
2531 | |
|
|
2532 | =back |
|
|
2533 | |
|
|
2534 | |
1760 | =head1 AUTHOR |
2535 | =head1 AUTHOR |
1761 | |
2536 | |
1762 | Marc Lehmann <libev@schmorp.de>. |
2537 | Marc Lehmann <libev@schmorp.de>. |
1763 | |
2538 | |