… | |
… | |
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 |
10 | |
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>. |
|
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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 occurring), 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 | |
15 | To do this, it must take more or less complete control over your process |
61 | To do this, it must take more or less complete control over your process |
16 | (or thread) by executing the I<event loop> handler, and will then |
62 | (or thread) by executing the I<event loop> handler, and will then |
17 | communicate events via a callback mechanism. |
63 | communicate events via a callback mechanism. |
… | |
… | |
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 | |
|
|
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 |
|
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104 | component C<stamp> might indicate, it is also used for time differences |
|
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105 | throughout libev. |
52 | |
106 | |
53 | =head1 GLOBAL FUNCTIONS |
107 | =head1 GLOBAL FUNCTIONS |
54 | |
108 | |
55 | These functions can be called anytime, even before initialising the |
109 | These functions can be called anytime, even before initialising the |
56 | library in any way. |
110 | library in any way. |
… | |
… | |
65 | |
119 | |
66 | =item int ev_version_major () |
120 | =item int ev_version_major () |
67 | |
121 | |
68 | =item int ev_version_minor () |
122 | =item int ev_version_minor () |
69 | |
123 | |
70 | 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 |
71 | 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 |
72 | 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 |
73 | 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 |
74 | version of the library your program was compiled against. |
128 | version of the library your program was compiled against. |
75 | |
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 | |
76 | 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, |
77 | as this indicates an incompatible change. Minor versions are usually |
134 | as this indicates an incompatible change. Minor versions are usually |
78 | 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 |
79 | not a problem. |
136 | not a problem. |
80 | |
137 | |
81 | 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 |
82 | version: |
139 | version. |
83 | |
140 | |
84 | assert (("libev version mismatch", |
141 | assert (("libev version mismatch", |
85 | ev_version_major () == EV_VERSION_MAJOR |
142 | ev_version_major () == EV_VERSION_MAJOR |
86 | && ev_version_minor () >= EV_VERSION_MINOR)); |
143 | && ev_version_minor () >= EV_VERSION_MINOR)); |
87 | |
144 | |
… | |
… | |
117 | |
174 | |
118 | See the description of C<ev_embed> watchers for more info. |
175 | See the description of C<ev_embed> watchers for more info. |
119 | |
176 | |
120 | =item ev_set_allocator (void *(*cb)(void *ptr, long size)) |
177 | =item ev_set_allocator (void *(*cb)(void *ptr, long size)) |
121 | |
178 | |
122 | Sets the allocation function to use (the prototype is similar to the |
179 | Sets the allocation function to use (the prototype is similar - the |
123 | 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 |
124 | 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 |
125 | 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 |
126 | destructive action. The default is your system realloc function. |
183 | potentially destructive action. The default is your system realloc |
|
|
184 | function. |
127 | |
185 | |
128 | You could override this function in high-availability programs to, say, |
186 | You could override this function in high-availability programs to, say, |
129 | 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, |
130 | 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. |
131 | |
189 | |
132 | 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 |
133 | retries: better than mine). |
191 | retries). |
134 | |
192 | |
135 | static void * |
193 | static void * |
136 | persistent_realloc (void *ptr, long size) |
194 | persistent_realloc (void *ptr, size_t size) |
137 | { |
195 | { |
138 | for (;;) |
196 | for (;;) |
139 | { |
197 | { |
140 | void *newptr = realloc (ptr, size); |
198 | void *newptr = realloc (ptr, size); |
141 | |
199 | |
… | |
… | |
157 | 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 |
158 | 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 |
159 | 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 |
160 | (such as abort). |
218 | (such as abort). |
161 | |
219 | |
162 | Example: do the same thing as libev does internally: |
220 | Example: This is basically the same thing that libev does internally, too. |
163 | |
221 | |
164 | static void |
222 | static void |
165 | fatal_error (const char *msg) |
223 | fatal_error (const char *msg) |
166 | { |
224 | { |
167 | perror (msg); |
225 | perror (msg); |
… | |
… | |
217 | C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will |
275 | C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will |
218 | 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 |
219 | 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 |
220 | around bugs. |
278 | around bugs. |
221 | |
279 | |
|
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280 | =item C<EVFLAG_FORKCHECK> |
|
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281 | |
|
|
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 | |
|
|
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 | |
222 | =item C<EVBACKEND_SELECT> (value 1, portable select backend) |
300 | =item C<EVBACKEND_SELECT> (value 1, portable select backend) |
223 | |
301 | |
224 | 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 |
225 | 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, |
226 | 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 |
… | |
… | |
253 | |
331 | |
254 | =item C<EVBACKEND_KQUEUE> (value 8, most BSD clones) |
332 | =item C<EVBACKEND_KQUEUE> (value 8, most BSD clones) |
255 | |
333 | |
256 | Kqueue deserves special mention, as at the time of this writing, it |
334 | Kqueue deserves special mention, as at the time of this writing, it |
257 | was broken on all BSDs except NetBSD (usually it doesn't work with |
335 | was broken on all BSDs except NetBSD (usually it doesn't work with |
258 | anything but sockets and pipes, except on Darwin, where of course its |
336 | anything but sockets and pipes, except on Darwin, where of course it's |
259 | completely useless). For this reason its not being "autodetected" |
337 | completely useless). For this reason it's not being "autodetected" |
260 | unless you explicitly specify it explicitly in the flags (i.e. using |
338 | unless you explicitly specify it explicitly in the flags (i.e. using |
261 | C<EVBACKEND_KQUEUE>). |
339 | C<EVBACKEND_KQUEUE>). |
262 | |
340 | |
263 | It scales in the same way as the epoll backend, but the interface to the |
341 | It scales in the same way as the epoll backend, but the interface to the |
264 | kernel is more efficient (which says nothing about its actual speed, of |
342 | kernel is more efficient (which says nothing about its actual speed, of |
… | |
… | |
313 | 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 |
314 | 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 |
315 | 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 |
316 | undefined behaviour (or a failed assertion if assertions are enabled). |
394 | undefined behaviour (or a failed assertion if assertions are enabled). |
317 | |
395 | |
318 | 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. |
319 | |
397 | |
320 | struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
398 | struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV); |
321 | if (!epoller) |
399 | if (!epoller) |
322 | fatal ("no epoll found here, maybe it hides under your chair"); |
400 | fatal ("no epoll found here, maybe it hides under your chair"); |
323 | |
401 | |
… | |
… | |
326 | Destroys the default loop again (frees all memory and kernel state |
404 | Destroys the default loop again (frees all memory and kernel state |
327 | 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 |
328 | 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 |
329 | responsibility to either stop all watchers cleanly yoursef I<before> |
407 | responsibility to either stop all watchers cleanly yoursef I<before> |
330 | 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 |
331 | 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 |
332 | for example). |
410 | for example). |
|
|
411 | |
|
|
412 | Note that certain global state, such as signal state, will not be freed by |
|
|
413 | this function, and related watchers (such as signal and child watchers) |
|
|
414 | would need to be stopped manually. |
|
|
415 | |
|
|
416 | In general it is not advisable to call this function except in the |
|
|
417 | rare occasion where you really need to free e.g. the signal handling |
|
|
418 | pipe fds. If you need dynamically allocated loops it is better to use |
|
|
419 | C<ev_loop_new> and C<ev_loop_destroy>). |
333 | |
420 | |
334 | =item ev_loop_destroy (loop) |
421 | =item ev_loop_destroy (loop) |
335 | |
422 | |
336 | 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 |
337 | earlier call to C<ev_loop_new>. |
424 | earlier call to C<ev_loop_new>. |
… | |
… | |
361 | |
448 | |
362 | 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 |
363 | 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 |
364 | 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. |
365 | |
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. |
|
|
462 | |
366 | =item unsigned int ev_backend (loop) |
463 | =item unsigned int ev_backend (loop) |
367 | |
464 | |
368 | 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 |
369 | use. |
466 | use. |
370 | |
467 | |
… | |
… | |
372 | |
469 | |
373 | Returns the current "event loop time", which is the time the event loop |
470 | Returns the current "event loop time", which is the time the event loop |
374 | received events and started processing them. This timestamp does not |
471 | received events and started processing them. This timestamp does not |
375 | change as long as callbacks are being processed, and this is also the base |
472 | change as long as callbacks are being processed, and this is also the base |
376 | time used for relative timers. You can treat it as the timestamp of the |
473 | time used for relative timers. You can treat it as the timestamp of the |
377 | event occuring (or more correctly, libev finding out about it). |
474 | event occurring (or more correctly, libev finding out about it). |
378 | |
475 | |
379 | =item ev_loop (loop, int flags) |
476 | =item ev_loop (loop, int flags) |
380 | |
477 | |
381 | Finally, this is it, the event handler. This function usually is called |
478 | Finally, this is it, the event handler. This function usually is called |
382 | after you initialised all your watchers and you want to start handling |
479 | after you initialised all your watchers and you want to start handling |
… | |
… | |
403 | 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 |
404 | usually a better approach for this kind of thing. |
501 | usually a better approach for this kind of thing. |
405 | |
502 | |
406 | Here are the gory details of what C<ev_loop> does: |
503 | Here are the gory details of what C<ev_loop> does: |
407 | |
504 | |
|
|
505 | - Before the first iteration, call any pending watchers. |
408 | * If there are no active watchers (reference count is zero), return. |
506 | * If there are no active watchers (reference count is zero), return. |
409 | - Queue prepare watchers and then call all outstanding watchers. |
507 | - Queue all prepare watchers and then call all outstanding watchers. |
410 | - If we have been forked, recreate the kernel state. |
508 | - If we have been forked, recreate the kernel state. |
411 | - Update the kernel state with all outstanding changes. |
509 | - Update the kernel state with all outstanding changes. |
412 | - Update the "event loop time". |
510 | - Update the "event loop time". |
413 | - Calculate for how long to block. |
511 | - Calculate for how long to block. |
414 | - Block the process, waiting for any events. |
512 | - Block the process, waiting for any events. |
… | |
… | |
422 | 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 |
423 | be handled here by queueing them when their watcher gets executed. |
521 | be handled here by queueing them when their watcher gets executed. |
424 | - 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 |
425 | were used, return, otherwise continue with step *. |
523 | were used, return, otherwise continue with step *. |
426 | |
524 | |
427 | 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 |
428 | anymore. |
526 | anymore. |
429 | |
527 | |
430 | ... queue jobs here, make sure they register event watchers as long |
528 | ... queue jobs here, make sure they register event watchers as long |
431 | ... 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..) |
432 | ev_loop (my_loop, 0); |
530 | ev_loop (my_loop, 0); |
… | |
… | |
452 | 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 |
453 | 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 |
454 | 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 |
455 | 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>. |
456 | |
554 | |
457 | 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> |
458 | running when nothing else is active. |
556 | running when nothing else is active. |
459 | |
557 | |
460 | struct dv_signal exitsig; |
558 | struct ev_signal exitsig; |
461 | ev_signal_init (&exitsig, sig_cb, SIGINT); |
559 | ev_signal_init (&exitsig, sig_cb, SIGINT); |
462 | ev_signal_start (myloop, &exitsig); |
560 | ev_signal_start (loop, &exitsig); |
463 | evf_unref (myloop); |
561 | evf_unref (loop); |
464 | |
562 | |
465 | Example: for some weird reason, unregister the above signal handler again. |
563 | Example: For some weird reason, unregister the above signal handler again. |
466 | |
564 | |
467 | ev_ref (myloop); |
565 | ev_ref (loop); |
468 | ev_signal_stop (myloop, &exitsig); |
566 | ev_signal_stop (loop, &exitsig); |
469 | |
567 | |
470 | =back |
568 | =back |
471 | |
569 | |
472 | |
570 | |
473 | =head1 ANATOMY OF A WATCHER |
571 | =head1 ANATOMY OF A WATCHER |
… | |
… | |
653 | =item bool ev_is_pending (ev_TYPE *watcher) |
751 | =item bool ev_is_pending (ev_TYPE *watcher) |
654 | |
752 | |
655 | 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 |
656 | 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 |
657 | 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 |
658 | 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 |
659 | 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). |
660 | |
759 | |
661 | =item callback = ev_cb (ev_TYPE *watcher) |
760 | =item callback ev_cb (ev_TYPE *watcher) |
662 | |
761 | |
663 | Returns the callback currently set on the watcher. |
762 | Returns the callback currently set on the watcher. |
664 | |
763 | |
665 | =item ev_cb_set (ev_TYPE *watcher, callback) |
764 | =item ev_cb_set (ev_TYPE *watcher, callback) |
666 | |
765 | |
667 | 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 |
668 | (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>. |
669 | |
808 | |
670 | =back |
809 | =back |
671 | |
810 | |
672 | |
811 | |
673 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
812 | =head2 ASSOCIATING CUSTOM DATA WITH A WATCHER |
… | |
… | |
694 | { |
833 | { |
695 | struct my_io *w = (struct my_io *)w_; |
834 | struct my_io *w = (struct my_io *)w_; |
696 | ... |
835 | ... |
697 | } |
836 | } |
698 | |
837 | |
699 | 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 |
700 | 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 | } |
701 | |
869 | |
702 | |
870 | |
703 | =head1 WATCHER TYPES |
871 | =head1 WATCHER TYPES |
704 | |
872 | |
705 | This section describes each watcher in detail, but will not repeat |
873 | This section describes each watcher in detail, but will not repeat |
… | |
… | |
750 | 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 |
751 | 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. |
752 | |
920 | |
753 | 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 |
754 | 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 |
755 | 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 |
756 | 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 |
757 | 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 |
758 | |
950 | |
759 | =over 4 |
951 | =over 4 |
760 | |
952 | |
761 | =item ev_io_init (ev_io *, callback, int fd, int events) |
953 | =item ev_io_init (ev_io *, callback, int fd, int events) |
762 | |
954 | |
… | |
… | |
774 | |
966 | |
775 | The events being watched. |
967 | The events being watched. |
776 | |
968 | |
777 | =back |
969 | =back |
778 | |
970 | |
779 | 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 |
780 | 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 |
781 | attempt to read a whole line in the callback: |
973 | attempt to read a whole line in the callback. |
782 | |
974 | |
783 | static void |
975 | static void |
784 | 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) |
785 | { |
977 | { |
786 | ev_io_stop (loop, w); |
978 | ev_io_stop (loop, w); |
… | |
… | |
816 | |
1008 | |
817 | 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, |
818 | 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 |
819 | order of execution is undefined. |
1011 | order of execution is undefined. |
820 | |
1012 | |
|
|
1013 | =head3 Watcher-Specific Functions and Data Members |
|
|
1014 | |
821 | =over 4 |
1015 | =over 4 |
822 | |
1016 | |
823 | =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) |
824 | |
1018 | |
825 | =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) |
… | |
… | |
838 | =item ev_timer_again (loop) |
1032 | =item ev_timer_again (loop) |
839 | |
1033 | |
840 | 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 |
841 | repeating. The exact semantics are: |
1035 | repeating. The exact semantics are: |
842 | |
1036 | |
|
|
1037 | If the timer is pending, its pending status is cleared. |
|
|
1038 | |
843 | If the timer is started but nonrepeating, stop it. |
1039 | If the timer is started but nonrepeating, stop it (as if it timed out). |
844 | |
1040 | |
845 | 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 |
846 | value), or reset the running timer to the repeat value. |
1042 | C<repeat> value), or reset the running timer to the C<repeat> value. |
847 | |
1043 | |
848 | 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 |
849 | example: Imagine you have a tcp connection and you want a so-called |
1045 | example: Imagine you have a tcp connection and you want a so-called idle |
850 | idle timeout, that is, you want to be called when there have been, |
1046 | timeout, that is, you want to be called when there have been, say, 60 |
851 | say, 60 seconds of inactivity on the socket. The easiest way to do |
1047 | seconds of inactivity on the socket. The easiest way to do this is to |
852 | this is to configure an C<ev_timer> with C<after>=C<repeat>=C<60> and calling |
1048 | configure an C<ev_timer> with a C<repeat> value of C<60> and then call |
853 | C<ev_timer_again> each time you successfully read or write some data. If |
1049 | C<ev_timer_again> each time you successfully read or write some data. If |
854 | you go into an idle state where you do not expect data to travel on the |
1050 | you go into an idle state where you do not expect data to travel on the |
855 | socket, you can stop the timer, and again will automatically restart it if |
1051 | socket, you can C<ev_timer_stop> the timer, and C<ev_timer_again> will |
856 | need be. |
1052 | automatically restart it if need be. |
857 | |
1053 | |
858 | You can also ignore the C<after> value and C<ev_timer_start> altogether |
1054 | That means you can ignore the C<after> value and C<ev_timer_start> |
859 | and only ever use the C<repeat> value: |
1055 | altogether and only ever use the C<repeat> value and C<ev_timer_again>: |
860 | |
1056 | |
861 | ev_timer_init (timer, callback, 0., 5.); |
1057 | ev_timer_init (timer, callback, 0., 5.); |
862 | ev_timer_again (loop, timer); |
1058 | ev_timer_again (loop, timer); |
863 | ... |
1059 | ... |
864 | timer->again = 17.; |
1060 | timer->again = 17.; |
865 | ev_timer_again (loop, timer); |
1061 | ev_timer_again (loop, timer); |
866 | ... |
1062 | ... |
867 | timer->again = 10.; |
1063 | timer->again = 10.; |
868 | ev_timer_again (loop, timer); |
1064 | ev_timer_again (loop, timer); |
869 | |
1065 | |
870 | This is more efficient then stopping/starting the timer eahc time you want |
1066 | This is more slightly efficient then stopping/starting the timer each time |
871 | to modify its timeout value. |
1067 | you want to modify its timeout value. |
872 | |
1068 | |
873 | =item ev_tstamp repeat [read-write] |
1069 | =item ev_tstamp repeat [read-write] |
874 | |
1070 | |
875 | The current C<repeat> value. Will be used each time the watcher times out |
1071 | The current C<repeat> value. Will be used each time the watcher times out |
876 | or C<ev_timer_again> is called and determines the next timeout (if any), |
1072 | or C<ev_timer_again> is called and determines the next timeout (if any), |
877 | which is also when any modifications are taken into account. |
1073 | which is also when any modifications are taken into account. |
878 | |
1074 | |
879 | =back |
1075 | =back |
880 | |
1076 | |
881 | Example: create a timer that fires after 60 seconds. |
1077 | Example: Create a timer that fires after 60 seconds. |
882 | |
1078 | |
883 | static void |
1079 | static void |
884 | 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) |
885 | { |
1081 | { |
886 | .. one minute over, w is actually stopped right here |
1082 | .. one minute over, w is actually stopped right here |
… | |
… | |
888 | |
1084 | |
889 | struct ev_timer mytimer; |
1085 | struct ev_timer mytimer; |
890 | ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
1086 | ev_timer_init (&mytimer, one_minute_cb, 60., 0.); |
891 | ev_timer_start (loop, &mytimer); |
1087 | ev_timer_start (loop, &mytimer); |
892 | |
1088 | |
893 | 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 |
894 | inactivity. |
1090 | inactivity. |
895 | |
1091 | |
896 | static void |
1092 | static void |
897 | 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) |
898 | { |
1094 | { |
… | |
… | |
918 | 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 |
919 | 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 |
920 | 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 () |
921 | + 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 |
922 | 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 |
923 | roughly 10 seconds later and of course not if you reset your system time |
1119 | roughly 10 seconds later). |
924 | again). |
|
|
925 | |
1120 | |
926 | 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 |
927 | triggering an event on eahc midnight, local time. |
1122 | triggering an event on each midnight, local time or other, complicated, |
|
|
1123 | rules. |
928 | |
1124 | |
929 | 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 |
930 | 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 |
931 | during the same loop iteration then order of execution is undefined. |
1127 | during the same loop iteration then order of execution is undefined. |
932 | |
1128 | |
|
|
1129 | =head3 Watcher-Specific Functions and Data Members |
|
|
1130 | |
933 | =over 4 |
1131 | =over 4 |
934 | |
1132 | |
935 | =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) |
936 | |
1134 | |
937 | =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) |
… | |
… | |
939 | 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 |
940 | operation, and we will explain them from simplest to complex: |
1138 | operation, and we will explain them from simplest to complex: |
941 | |
1139 | |
942 | =over 4 |
1140 | =over 4 |
943 | |
1141 | |
944 | =item * absolute timer (interval = reschedule_cb = 0) |
1142 | =item * absolute timer (at = time, interval = reschedule_cb = 0) |
945 | |
1143 | |
946 | 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 |
947 | 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, |
948 | 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 |
949 | system time reaches or surpasses this time. |
1147 | system time reaches or surpasses this time. |
950 | |
1148 | |
951 | =item * non-repeating interval timer (interval > 0, reschedule_cb = 0) |
1149 | =item * non-repeating interval timer (at = offset, interval > 0, reschedule_cb = 0) |
952 | |
1150 | |
953 | 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 |
954 | 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) |
955 | of any time jumps. |
1153 | and then repeat, regardless of any time jumps. |
956 | |
1154 | |
957 | 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 |
958 | time: |
1156 | time: |
959 | |
1157 | |
960 | ev_periodic_set (&periodic, 0., 3600., 0); |
1158 | ev_periodic_set (&periodic, 0., 3600., 0); |
… | |
… | |
966 | |
1164 | |
967 | 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 |
968 | 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 |
969 | 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. |
970 | |
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 | |
971 | =item * manual reschedule mode (reschedule_cb = callback) |
1173 | =item * manual reschedule mode (at and interval ignored, reschedule_cb = callback) |
972 | |
1174 | |
973 | 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 |
974 | ignored. Instead, each time the periodic watcher gets scheduled, the |
1176 | ignored. Instead, each time the periodic watcher gets scheduled, the |
975 | 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 |
976 | current time as second argument. |
1178 | current time as second argument. |
977 | |
1179 | |
978 | 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, |
979 | 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, |
980 | 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 |
981 | starting a prepare watcher). |
1183 | starting an C<ev_prepare> watcher, which is legal). |
982 | |
1184 | |
983 | 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, |
984 | ev_tstamp now)>, e.g.: |
1186 | ev_tstamp now)>, e.g.: |
985 | |
1187 | |
986 | 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) |
… | |
… | |
1009 | 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 |
1010 | when you changed some parameters or the reschedule callback would return |
1212 | when you changed some parameters or the reschedule callback would return |
1011 | 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 |
1012 | program when the crontabs have changed). |
1214 | program when the crontabs have changed). |
1013 | |
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 | |
1014 | =item ev_tstamp interval [read-write] |
1224 | =item ev_tstamp interval [read-write] |
1015 | |
1225 | |
1016 | The current interval value. Can be modified any time, but changes only |
1226 | The current interval value. Can be modified any time, but changes only |
1017 | take effect when the periodic timer fires or C<ev_periodic_again> is being |
1227 | take effect when the periodic timer fires or C<ev_periodic_again> is being |
1018 | called. |
1228 | called. |
… | |
… | |
1021 | |
1231 | |
1022 | The current reschedule callback, or C<0>, if this functionality is |
1232 | The current reschedule callback, or C<0>, if this functionality is |
1023 | switched off. Can be changed any time, but changes only take effect when |
1233 | switched off. Can be changed any time, but changes only take effect when |
1024 | the periodic timer fires or C<ev_periodic_again> is being called. |
1234 | the periodic timer fires or C<ev_periodic_again> is being called. |
1025 | |
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 | |
1026 | =back |
1241 | =back |
1027 | |
1242 | |
1028 | Example: call a callback every hour, or, more precisely, whenever the |
1243 | Example: Call a callback every hour, or, more precisely, whenever the |
1029 | system clock is divisible by 3600. The callback invocation times have |
1244 | system clock is divisible by 3600. The callback invocation times have |
1030 | potentially a lot of jittering, but good long-term stability. |
1245 | potentially a lot of jittering, but good long-term stability. |
1031 | |
1246 | |
1032 | static void |
1247 | static void |
1033 | 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) |
… | |
… | |
1037 | |
1252 | |
1038 | struct ev_periodic hourly_tick; |
1253 | struct ev_periodic hourly_tick; |
1039 | ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1254 | ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0); |
1040 | ev_periodic_start (loop, &hourly_tick); |
1255 | ev_periodic_start (loop, &hourly_tick); |
1041 | |
1256 | |
1042 | 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: |
1043 | |
1258 | |
1044 | #include <math.h> |
1259 | #include <math.h> |
1045 | |
1260 | |
1046 | static ev_tstamp |
1261 | static ev_tstamp |
1047 | my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
1262 | my_scheduler_cb (struct ev_periodic *w, ev_tstamp now) |
… | |
… | |
1049 | return fmod (now, 3600.) + 3600.; |
1264 | return fmod (now, 3600.) + 3600.; |
1050 | } |
1265 | } |
1051 | |
1266 | |
1052 | 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); |
1053 | |
1268 | |
1054 | Example: call a callback every hour, starting now: |
1269 | Example: Call a callback every hour, starting now: |
1055 | |
1270 | |
1056 | struct ev_periodic hourly_tick; |
1271 | struct ev_periodic hourly_tick; |
1057 | ev_periodic_init (&hourly_tick, clock_cb, |
1272 | ev_periodic_init (&hourly_tick, clock_cb, |
1058 | fmod (ev_now (loop), 3600.), 3600., 0); |
1273 | fmod (ev_now (loop), 3600.), 3600., 0); |
1059 | ev_periodic_start (loop, &hourly_tick); |
1274 | ev_periodic_start (loop, &hourly_tick); |
… | |
… | |
1071 | 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 |
1072 | 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 |
1073 | 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 |
1074 | SIG_DFL (regardless of what it was set to before). |
1289 | SIG_DFL (regardless of what it was set to before). |
1075 | |
1290 | |
|
|
1291 | =head3 Watcher-Specific Functions and Data Members |
|
|
1292 | |
1076 | =over 4 |
1293 | =over 4 |
1077 | |
1294 | |
1078 | =item ev_signal_init (ev_signal *, callback, int signum) |
1295 | =item ev_signal_init (ev_signal *, callback, int signum) |
1079 | |
1296 | |
1080 | =item ev_signal_set (ev_signal *, int signum) |
1297 | =item ev_signal_set (ev_signal *, int signum) |
… | |
… | |
1091 | |
1308 | |
1092 | =head2 C<ev_child> - watch out for process status changes |
1309 | =head2 C<ev_child> - watch out for process status changes |
1093 | |
1310 | |
1094 | 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 |
1095 | 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 |
1096 | |
1315 | |
1097 | =over 4 |
1316 | =over 4 |
1098 | |
1317 | |
1099 | =item ev_child_init (ev_child *, callback, int pid) |
1318 | =item ev_child_init (ev_child *, callback, int pid) |
1100 | |
1319 | |
… | |
… | |
1120 | The process exit/trace status caused by C<rpid> (see your systems |
1339 | The process exit/trace status caused by C<rpid> (see your systems |
1121 | C<waitpid> and C<sys/wait.h> documentation for details). |
1340 | C<waitpid> and C<sys/wait.h> documentation for details). |
1122 | |
1341 | |
1123 | =back |
1342 | =back |
1124 | |
1343 | |
1125 | Example: try to exit cleanly on SIGINT and SIGTERM. |
1344 | Example: Try to exit cleanly on SIGINT and SIGTERM. |
1126 | |
1345 | |
1127 | static void |
1346 | static void |
1128 | 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) |
1129 | { |
1348 | { |
1130 | ev_unloop (loop, EVUNLOOP_ALL); |
1349 | ev_unloop (loop, EVUNLOOP_ALL); |
… | |
… | |
1145 | not exist" is a status change like any other. The condition "path does |
1364 | not exist" is a status change like any other. The condition "path does |
1146 | not exist" is signified by the C<st_nlink> field being zero (which is |
1365 | not exist" is signified by the C<st_nlink> field being zero (which is |
1147 | otherwise always forced to be at least one) and all the other fields of |
1366 | otherwise always forced to be at least one) and all the other fields of |
1148 | the stat buffer having unspecified contents. |
1367 | the stat buffer having unspecified contents. |
1149 | |
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 | |
1150 | Since there is no standard to do this, the portable implementation simply |
1372 | Since there is no standard to do this, the portable implementation simply |
1151 | calls C<stat (2)> regulalry on the path to see if it changed somehow. You |
1373 | calls C<stat (2)> regularly on the path to see if it changed somehow. You |
1152 | can specify a recommended polling interval for this case. If you specify |
1374 | can specify a recommended polling interval for this case. If you specify |
1153 | a polling interval of C<0> (highly recommended!) then a I<suitable, |
1375 | a polling interval of C<0> (highly recommended!) then a I<suitable, |
1154 | unspecified default> value will be used (which you can expect to be around |
1376 | unspecified default> value will be used (which you can expect to be around |
1155 | five seconds, although this might change dynamically). Libev will also |
1377 | five seconds, although this might change dynamically). Libev will also |
1156 | impose a minimum interval which is currently around C<0.1>, but thats |
1378 | impose a minimum interval which is currently around C<0.1>, but thats |
… | |
… | |
1158 | |
1380 | |
1159 | This watcher type is not meant for massive numbers of stat watchers, |
1381 | This watcher type is not meant for massive numbers of stat watchers, |
1160 | as even with OS-supported change notifications, this can be |
1382 | as even with OS-supported change notifications, this can be |
1161 | resource-intensive. |
1383 | resource-intensive. |
1162 | |
1384 | |
1163 | At the time of this writing, no specific OS backends are implemented, but |
1385 | At the time of this writing, only the Linux inotify interface is |
1164 | if demand increases, at least a kqueue and inotify backend will be added. |
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 |
1165 | |
1394 | |
1166 | =over 4 |
1395 | =over 4 |
1167 | |
1396 | |
1168 | =item ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval) |
1397 | =item ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval) |
1169 | |
1398 | |
… | |
… | |
1233 | ev_stat_start (loop, &passwd); |
1462 | ev_stat_start (loop, &passwd); |
1234 | |
1463 | |
1235 | |
1464 | |
1236 | =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... |
1237 | |
1466 | |
1238 | 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 |
1239 | (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 |
1240 | as your process is busy handling sockets or timeouts (or even signals, |
1469 | count). |
1241 | imagine) it will not be triggered. But when your process is idle all idle |
1470 | |
1242 | 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 |
1243 | until stopped, that is, or your process receives more events and becomes |
1475 | iteration - until stopped, that is, or your process receives more events |
1244 | busy. |
1476 | and becomes busy again with higher priority stuff. |
1245 | |
1477 | |
1246 | 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 |
1247 | active, the process will not block when waiting for new events. |
1479 | active, the process will not block when waiting for new events. |
1248 | |
1480 | |
1249 | Apart from keeping your process non-blocking (which is a useful |
1481 | Apart from keeping your process non-blocking (which is a useful |
1250 | 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 |
1251 | "pseudo-background processing", or delay processing stuff to after the |
1483 | "pseudo-background processing", or delay processing stuff to after the |
1252 | event loop has handled all outstanding events. |
1484 | event loop has handled all outstanding events. |
1253 | |
1485 | |
|
|
1486 | =head3 Watcher-Specific Functions and Data Members |
|
|
1487 | |
1254 | =over 4 |
1488 | =over 4 |
1255 | |
1489 | |
1256 | =item ev_idle_init (ev_signal *, callback) |
1490 | =item ev_idle_init (ev_signal *, callback) |
1257 | |
1491 | |
1258 | 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 |
1259 | 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, |
1260 | believe me. |
1494 | believe me. |
1261 | |
1495 | |
1262 | =back |
1496 | =back |
1263 | |
1497 | |
1264 | 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 |
1265 | callback, free it. Alos, use no error checking, as usual. |
1499 | callback, free it. Also, use no error checking, as usual. |
1266 | |
1500 | |
1267 | static void |
1501 | static void |
1268 | 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) |
1269 | { |
1503 | { |
1270 | free (w); |
1504 | free (w); |
… | |
… | |
1315 | 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 |
1316 | 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 |
1317 | loop from blocking if lower-priority coroutines are active, thus mapping |
1551 | loop from blocking if lower-priority coroutines are active, thus mapping |
1318 | low-priority coroutines to idle/background tasks). |
1552 | low-priority coroutines to idle/background tasks). |
1319 | |
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 | |
1320 | =over 4 |
1566 | =over 4 |
1321 | |
1567 | |
1322 | =item ev_prepare_init (ev_prepare *, callback) |
1568 | =item ev_prepare_init (ev_prepare *, callback) |
1323 | |
1569 | |
1324 | =item ev_check_init (ev_check *, callback) |
1570 | =item ev_check_init (ev_check *, callback) |
… | |
… | |
1327 | 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> |
1328 | macros, but using them is utterly, utterly and completely pointless. |
1574 | macros, but using them is utterly, utterly and completely pointless. |
1329 | |
1575 | |
1330 | =back |
1576 | =back |
1331 | |
1577 | |
1332 | 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 |
1333 | 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, |
1334 | 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 |
1335 | 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. |
1336 | |
1590 | |
1337 | static ev_io iow [nfd]; |
1591 | static ev_io iow [nfd]; |
1338 | static ev_timer tw; |
1592 | static ev_timer tw; |
1339 | |
1593 | |
1340 | static void |
1594 | static void |
1341 | io_cb (ev_loop *loop, ev_io *w, int revents) |
1595 | io_cb (ev_loop *loop, ev_io *w, int revents) |
1342 | { |
1596 | { |
1343 | // set the relevant poll flags |
|
|
1344 | // could also call adns_processreadable etc. here |
|
|
1345 | struct pollfd *fd = (struct pollfd *)w->data; |
|
|
1346 | if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1347 | if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1348 | } |
1597 | } |
1349 | |
1598 | |
1350 | // create io watchers for each fd and a timer before blocking |
1599 | // create io watchers for each fd and a timer before blocking |
1351 | static void |
1600 | static void |
1352 | adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1601 | adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
1353 | { |
1602 | { |
1354 | int timeout = 3600000;truct pollfd fds [nfd]; |
1603 | int timeout = 3600000; |
|
|
1604 | struct pollfd fds [nfd]; |
1355 | // actual code will need to loop here and realloc etc. |
1605 | // actual code will need to loop here and realloc etc. |
1356 | adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1606 | adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
1357 | |
1607 | |
1358 | /* 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 */ |
1359 | ev_timer_init (&tw, 0, timeout * 1e-3); |
1609 | ev_timer_init (&tw, 0, timeout * 1e-3); |
1360 | ev_timer_start (loop, &tw); |
1610 | ev_timer_start (loop, &tw); |
1361 | |
1611 | |
1362 | // create on ev_io per pollfd |
1612 | // create one ev_io per pollfd |
1363 | for (int i = 0; i < nfd; ++i) |
1613 | for (int i = 0; i < nfd; ++i) |
1364 | { |
1614 | { |
1365 | ev_io_init (iow + i, io_cb, fds [i].fd, |
1615 | ev_io_init (iow + i, io_cb, fds [i].fd, |
1366 | ((fds [i].events & POLLIN ? EV_READ : 0) |
1616 | ((fds [i].events & POLLIN ? EV_READ : 0) |
1367 | | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1617 | | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
1368 | |
1618 | |
1369 | fds [i].revents = 0; |
1619 | fds [i].revents = 0; |
1370 | iow [i].data = fds + i; |
|
|
1371 | ev_io_start (loop, iow + i); |
1620 | ev_io_start (loop, iow + i); |
1372 | } |
1621 | } |
1373 | } |
1622 | } |
1374 | |
1623 | |
1375 | // stop all watchers after blocking |
1624 | // stop all watchers after blocking |
… | |
… | |
1377 | adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1626 | adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
1378 | { |
1627 | { |
1379 | ev_timer_stop (loop, &tw); |
1628 | ev_timer_stop (loop, &tw); |
1380 | |
1629 | |
1381 | 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 |
1382 | ev_io_stop (loop, iow + i); |
1640 | ev_io_stop (loop, iow + i); |
|
|
1641 | } |
1383 | |
1642 | |
1384 | 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; |
1385 | } |
1703 | } |
1386 | |
1704 | |
1387 | |
1705 | |
1388 | =head2 C<ev_embed> - when one backend isn't enough... |
1706 | =head2 C<ev_embed> - when one backend isn't enough... |
1389 | |
1707 | |
… | |
… | |
1453 | ev_embed_start (loop_hi, &embed); |
1771 | ev_embed_start (loop_hi, &embed); |
1454 | } |
1772 | } |
1455 | else |
1773 | else |
1456 | loop_lo = loop_hi; |
1774 | loop_lo = loop_hi; |
1457 | |
1775 | |
|
|
1776 | =head3 Watcher-Specific Functions and Data Members |
|
|
1777 | |
1458 | =over 4 |
1778 | =over 4 |
1459 | |
1779 | |
1460 | =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) |
1461 | |
1781 | |
1462 | =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) |
… | |
… | |
1471 | |
1791 | |
1472 | 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 |
1473 | 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 |
1474 | apropriate way for embedded loops. |
1794 | apropriate way for embedded loops. |
1475 | |
1795 | |
1476 | =item struct ev_loop *loop [read-only] |
1796 | =item struct ev_loop *other [read-only] |
1477 | |
1797 | |
1478 | The embedded event loop. |
1798 | The embedded event loop. |
1479 | |
1799 | |
1480 | =back |
1800 | =back |
1481 | |
1801 | |
… | |
… | |
1488 | event loop blocks next and before C<ev_check> watchers are being called, |
1808 | event loop blocks next and before C<ev_check> watchers are being called, |
1489 | and only in the child after the fork. If whoever good citizen calling |
1809 | and only in the child after the fork. If whoever good citizen calling |
1490 | C<ev_default_fork> cheats and calls it in the wrong process, the fork |
1810 | C<ev_default_fork> cheats and calls it in the wrong process, the fork |
1491 | handlers will be invoked, too, of course. |
1811 | handlers will be invoked, too, of course. |
1492 | |
1812 | |
|
|
1813 | =head3 Watcher-Specific Functions and Data Members |
|
|
1814 | |
1493 | =over 4 |
1815 | =over 4 |
1494 | |
1816 | |
1495 | =item ev_fork_init (ev_signal *, callback) |
1817 | =item ev_fork_init (ev_signal *, callback) |
1496 | |
1818 | |
1497 | Initialises and configures the fork watcher - it has no parameters of any |
1819 | Initialises and configures the fork watcher - it has no parameters of any |
… | |
… | |
1593 | |
1915 | |
1594 | To use it, |
1916 | To use it, |
1595 | |
1917 | |
1596 | #include <ev++.h> |
1918 | #include <ev++.h> |
1597 | |
1919 | |
1598 | (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 |
1599 | 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 |
1600 | 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>. |
1601 | |
1924 | |
1602 | 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++ |
1603 | 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). |
1604 | |
1935 | |
1605 | 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: |
1606 | |
1937 | |
1607 | =over 4 |
1938 | =over 4 |
1608 | |
1939 | |
… | |
… | |
1624 | |
1955 | |
1625 | All of those classes have these methods: |
1956 | All of those classes have these methods: |
1626 | |
1957 | |
1627 | =over 4 |
1958 | =over 4 |
1628 | |
1959 | |
1629 | =item ev::TYPE::TYPE (object *, object::method *) |
1960 | =item ev::TYPE::TYPE () |
1630 | |
1961 | |
1631 | =item ev::TYPE::TYPE (object *, object::method *, struct ev_loop *) |
1962 | =item ev::TYPE::TYPE (struct ev_loop *) |
1632 | |
1963 | |
1633 | =item ev::TYPE::~TYPE |
1964 | =item ev::TYPE::~TYPE |
1634 | |
1965 | |
1635 | 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 |
1636 | the event handler callback to call in this class. The constructor calls |
1967 | with. If it is omitted, it will use C<EV_DEFAULT>. |
1637 | C<ev_init> for you, which means you have to call the C<set> method |
1968 | |
1638 | 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 |
1639 | 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). |
1640 | |
1977 | |
1641 | 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> (); |
1642 | |
2018 | |
1643 | =item w->set (struct ev_loop *) |
2019 | =item w->set (struct ev_loop *) |
1644 | |
2020 | |
1645 | 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 |
1646 | do this when the watcher is inactive (and not pending either). |
2022 | do this when the watcher is inactive (and not pending either). |
1647 | |
2023 | |
1648 | =item w->set ([args]) |
2024 | =item w->set ([args]) |
1649 | |
2025 | |
1650 | 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 |
1651 | 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 |
1652 | automatically stopped and restarted. |
2028 | automatically stopped and restarted when reconfiguring it with this |
|
|
2029 | method. |
1653 | |
2030 | |
1654 | =item w->start () |
2031 | =item w->start () |
1655 | |
2032 | |
1656 | 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 |
1657 | constructor already takes the loop. |
2034 | constructor already stores the event loop. |
1658 | |
2035 | |
1659 | =item w->stop () |
2036 | =item w->stop () |
1660 | |
2037 | |
1661 | 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. |
1662 | |
2039 | |
1663 | =item w->again () C<ev::timer>, C<ev::periodic> only |
2040 | =item w->again () (C<ev::timer>, C<ev::periodic> only) |
1664 | |
2041 | |
1665 | 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 |
1666 | C<ev_TYPE_again> function. |
2043 | C<ev_TYPE_again> function. |
1667 | |
2044 | |
1668 | =item w->sweep () C<ev::embed> only |
2045 | =item w->sweep () (C<ev::embed> only) |
1669 | |
2046 | |
1670 | Invokes C<ev_embed_sweep>. |
2047 | Invokes C<ev_embed_sweep>. |
1671 | |
2048 | |
1672 | =item w->update () C<ev::stat> only |
2049 | =item w->update () (C<ev::stat> only) |
1673 | |
2050 | |
1674 | Invokes C<ev_stat_stat>. |
2051 | Invokes C<ev_stat_stat>. |
1675 | |
2052 | |
1676 | =back |
2053 | =back |
1677 | |
2054 | |
… | |
… | |
1687 | |
2064 | |
1688 | myclass (); |
2065 | myclass (); |
1689 | } |
2066 | } |
1690 | |
2067 | |
1691 | myclass::myclass (int fd) |
2068 | myclass::myclass (int fd) |
1692 | : io (this, &myclass::io_cb), |
|
|
1693 | idle (this, &myclass::idle_cb) |
|
|
1694 | { |
2069 | { |
|
|
2070 | io .set <myclass, &myclass::io_cb > (this); |
|
|
2071 | idle.set <myclass, &myclass::idle_cb> (this); |
|
|
2072 | |
1695 | io.start (fd, ev::READ); |
2073 | io.start (fd, ev::READ); |
1696 | } |
2074 | } |
1697 | |
2075 | |
1698 | |
2076 | |
1699 | =head1 MACRO MAGIC |
2077 | =head1 MACRO MAGIC |
1700 | |
2078 | |
1701 | Libev can be compiled with a variety of options, the most fundemantal is |
2079 | Libev can be compiled with a variety of options, the most fundamantal |
1702 | C<EV_MULTIPLICITY>. This option determines wether (most) functions and |
2080 | of which is C<EV_MULTIPLICITY>. This option determines whether (most) |
1703 | callbacks have an initial C<struct ev_loop *> argument. |
2081 | functions and callbacks have an initial C<struct ev_loop *> argument. |
1704 | |
2082 | |
1705 | To make it easier to write programs that cope with either variant, the |
2083 | To make it easier to write programs that cope with either variant, the |
1706 | following macros are defined: |
2084 | following macros are defined: |
1707 | |
2085 | |
1708 | =over 4 |
2086 | =over 4 |
… | |
… | |
1740 | Similar to the other two macros, this gives you the value of the default |
2118 | Similar to the other two macros, this gives you the value of the default |
1741 | loop, if multiple loops are supported ("ev loop default"). |
2119 | loop, if multiple loops are supported ("ev loop default"). |
1742 | |
2120 | |
1743 | =back |
2121 | =back |
1744 | |
2122 | |
1745 | Example: Declare and initialise a check watcher, working regardless of |
2123 | Example: Declare and initialise a check watcher, utilising the above |
1746 | wether multiple loops are supported or not. |
2124 | macros so it will work regardless of whether multiple loops are supported |
|
|
2125 | or not. |
1747 | |
2126 | |
1748 | static void |
2127 | static void |
1749 | check_cb (EV_P_ ev_timer *w, int revents) |
2128 | check_cb (EV_P_ ev_timer *w, int revents) |
1750 | { |
2129 | { |
1751 | ev_check_stop (EV_A_ w); |
2130 | ev_check_stop (EV_A_ w); |
… | |
… | |
1754 | ev_check check; |
2133 | ev_check check; |
1755 | ev_check_init (&check, check_cb); |
2134 | ev_check_init (&check, check_cb); |
1756 | ev_check_start (EV_DEFAULT_ &check); |
2135 | ev_check_start (EV_DEFAULT_ &check); |
1757 | ev_loop (EV_DEFAULT_ 0); |
2136 | ev_loop (EV_DEFAULT_ 0); |
1758 | |
2137 | |
1759 | |
|
|
1760 | =head1 EMBEDDING |
2138 | =head1 EMBEDDING |
1761 | |
2139 | |
1762 | Libev can (and often is) directly embedded into host |
2140 | Libev can (and often is) directly embedded into host |
1763 | applications. Examples of applications that embed it include the Deliantra |
2141 | applications. Examples of applications that embed it include the Deliantra |
1764 | Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe) |
2142 | Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe) |
1765 | and rxvt-unicode. |
2143 | and rxvt-unicode. |
1766 | |
2144 | |
1767 | The goal is to enable you to just copy the neecssary files into your |
2145 | The goal is to enable you to just copy the necessary files into your |
1768 | source directory without having to change even a single line in them, so |
2146 | source directory without having to change even a single line in them, so |
1769 | you can easily upgrade by simply copying (or having a checked-out copy of |
2147 | you can easily upgrade by simply copying (or having a checked-out copy of |
1770 | libev somewhere in your source tree). |
2148 | libev somewhere in your source tree). |
1771 | |
2149 | |
1772 | =head2 FILESETS |
2150 | =head2 FILESETS |
… | |
… | |
1803 | ev_vars.h |
2181 | ev_vars.h |
1804 | ev_wrap.h |
2182 | ev_wrap.h |
1805 | |
2183 | |
1806 | ev_win32.c required on win32 platforms only |
2184 | ev_win32.c required on win32 platforms only |
1807 | |
2185 | |
1808 | 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) |
1809 | 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) |
1810 | 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) |
1811 | 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) |
1812 | 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) |
1813 | |
2191 | |
… | |
… | |
1862 | |
2240 | |
1863 | If defined to be C<1>, libev will try to detect the availability of the |
2241 | If defined to be C<1>, libev will try to detect the availability of the |
1864 | monotonic clock option at both compiletime and runtime. Otherwise no use |
2242 | monotonic clock option at both compiletime and runtime. Otherwise no use |
1865 | of the monotonic clock option will be attempted. If you enable this, you |
2243 | of the monotonic clock option will be attempted. If you enable this, you |
1866 | usually have to link against librt or something similar. Enabling it when |
2244 | usually have to link against librt or something similar. Enabling it when |
1867 | the functionality isn't available is safe, though, althoguh you have |
2245 | the functionality isn't available is safe, though, although you have |
1868 | to make sure you link against any libraries where the C<clock_gettime> |
2246 | to make sure you link against any libraries where the C<clock_gettime> |
1869 | function is hiding in (often F<-lrt>). |
2247 | function is hiding in (often F<-lrt>). |
1870 | |
2248 | |
1871 | =item EV_USE_REALTIME |
2249 | =item EV_USE_REALTIME |
1872 | |
2250 | |
1873 | If defined to be C<1>, libev will try to detect the availability of the |
2251 | If defined to be C<1>, libev will try to detect the availability of the |
1874 | realtime clock option at compiletime (and assume its availability at |
2252 | realtime clock option at compiletime (and assume its availability at |
1875 | runtime if successful). Otherwise no use of the realtime clock option will |
2253 | runtime if successful). Otherwise no use of the realtime clock option will |
1876 | be attempted. This effectively replaces C<gettimeofday> by C<clock_get |
2254 | be attempted. This effectively replaces C<gettimeofday> by C<clock_get |
1877 | (CLOCK_REALTIME, ...)> and will not normally affect correctness. See tzhe note about libraries |
2255 | (CLOCK_REALTIME, ...)> and will not normally affect correctness. See the |
1878 | in the description of C<EV_USE_MONOTONIC>, though. |
2256 | note about libraries in the description of C<EV_USE_MONOTONIC>, though. |
1879 | |
2257 | |
1880 | =item EV_USE_SELECT |
2258 | =item EV_USE_SELECT |
1881 | |
2259 | |
1882 | If undefined or defined to be C<1>, libev will compile in support for the |
2260 | If undefined or defined to be C<1>, libev will compile in support for the |
1883 | C<select>(2) backend. No attempt at autodetection will be done: if no |
2261 | C<select>(2) backend. No attempt at autodetection will be done: if no |
… | |
… | |
1938 | |
2316 | |
1939 | =item EV_USE_DEVPOLL |
2317 | =item EV_USE_DEVPOLL |
1940 | |
2318 | |
1941 | reserved for future expansion, works like the USE symbols above. |
2319 | reserved for future expansion, works like the USE symbols above. |
1942 | |
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 | |
1943 | =item EV_H |
2327 | =item EV_H |
1944 | |
2328 | |
1945 | 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 |
1946 | 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 |
1947 | 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. |
… | |
… | |
1970 | 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 |
1971 | additional independent event loops. Otherwise there will be no support |
2355 | additional independent event loops. Otherwise there will be no support |
1972 | 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 |
1973 | argument. Instead, all functions act on the single default loop. |
2357 | argument. Instead, all functions act on the single default loop. |
1974 | |
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 | |
1975 | =item EV_PERIODIC_ENABLE |
2376 | =item EV_PERIODIC_ENABLE |
1976 | |
2377 | |
1977 | If undefined or defined to be C<1>, then periodic timers are supported. If |
2378 | If undefined or defined to be C<1>, then periodic timers are supported. If |
1978 | defined to be C<0>, then they are not. Disabling them saves a few kB of |
2379 | defined to be C<0>, then they are not. Disabling them saves a few kB of |
1979 | code. |
2380 | code. |
1980 | |
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 | |
1981 | =item EV_EMBED_ENABLE |
2388 | =item EV_EMBED_ENABLE |
1982 | |
2389 | |
1983 | If undefined or defined to be C<1>, then embed watchers are supported. If |
2390 | If undefined or defined to be C<1>, then embed watchers are supported. If |
1984 | defined to be C<0>, then they are not. |
2391 | defined to be C<0>, then they are not. |
1985 | |
2392 | |
… | |
… | |
2002 | =item EV_PID_HASHSIZE |
2409 | =item EV_PID_HASHSIZE |
2003 | |
2410 | |
2004 | C<ev_child> watchers use a small hash table to distribute workload by |
2411 | C<ev_child> watchers use a small hash table to distribute workload by |
2005 | pid. The default size is C<16> (or C<1> with C<EV_MINIMAL>), usually more |
2412 | pid. The default size is C<16> (or C<1> with C<EV_MINIMAL>), usually more |
2006 | than enough. If you need to manage thousands of children you might want to |
2413 | than enough. If you need to manage thousands of children you might want to |
2007 | increase this value. |
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). |
2008 | |
2423 | |
2009 | =item EV_COMMON |
2424 | =item EV_COMMON |
2010 | |
2425 | |
2011 | 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 |
2012 | 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 |
… | |
… | |
2025 | |
2440 | |
2026 | =item ev_set_cb (ev, cb) |
2441 | =item ev_set_cb (ev, cb) |
2027 | |
2442 | |
2028 | Can be used to change the callback member declaration in each watcher, |
2443 | Can be used to change the callback member declaration in each watcher, |
2029 | and the way callbacks are invoked and set. Must expand to a struct member |
2444 | and the way callbacks are invoked and set. Must expand to a struct member |
2030 | definition and a statement, respectively. See the F<ev.v> header file for |
2445 | definition and a statement, respectively. See the F<ev.h> header file for |
2031 | their default definitions. One possible use for overriding these is to |
2446 | their default definitions. One possible use for overriding these is to |
2032 | avoid the C<struct ev_loop *> as first argument in all cases, or to use |
2447 | avoid the C<struct ev_loop *> as first argument in all cases, or to use |
2033 | method calls instead of plain function calls in C++. |
2448 | method calls instead of plain function calls in C++. |
|
|
2449 | |
|
|
2450 | =head2 EXPORTED API SYMBOLS |
|
|
2451 | |
|
|
2452 | If you need to re-export the API (e.g. via a dll) and you need a list of |
|
|
2453 | exported symbols, you can use the provided F<Symbol.*> files which list |
|
|
2454 | all public symbols, one per line: |
|
|
2455 | |
|
|
2456 | Symbols.ev for libev proper |
|
|
2457 | Symbols.event for the libevent emulation |
|
|
2458 | |
|
|
2459 | This can also be used to rename all public symbols to avoid clashes with |
|
|
2460 | multiple versions of libev linked together (which is obviously bad in |
|
|
2461 | itself, but sometimes it is inconvinient to avoid this). |
|
|
2462 | |
|
|
2463 | A sed command like this will create wrapper C<#define>'s that you need to |
|
|
2464 | include before including F<ev.h>: |
|
|
2465 | |
|
|
2466 | <Symbols.ev sed -e "s/.*/#define & myprefix_&/" >wrap.h |
|
|
2467 | |
|
|
2468 | This would create a file F<wrap.h> which essentially looks like this: |
|
|
2469 | |
|
|
2470 | #define ev_backend myprefix_ev_backend |
|
|
2471 | #define ev_check_start myprefix_ev_check_start |
|
|
2472 | #define ev_check_stop myprefix_ev_check_stop |
|
|
2473 | ... |
2034 | |
2474 | |
2035 | =head2 EXAMPLES |
2475 | =head2 EXAMPLES |
2036 | |
2476 | |
2037 | For a real-world example of a program the includes libev |
2477 | For a real-world example of a program the includes libev |
2038 | verbatim, you can have a look at the EV perl module |
2478 | verbatim, you can have a look at the EV perl module |
… | |
… | |
2041 | interface) and F<EV.xs> (implementation) files. Only the F<EV.xs> file |
2481 | interface) and F<EV.xs> (implementation) files. Only the F<EV.xs> file |
2042 | will be compiled. It is pretty complex because it provides its own header |
2482 | will be compiled. It is pretty complex because it provides its own header |
2043 | file. |
2483 | file. |
2044 | |
2484 | |
2045 | The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file |
2485 | The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file |
2046 | that everybody includes and which overrides some autoconf choices: |
2486 | that everybody includes and which overrides some configure choices: |
2047 | |
2487 | |
|
|
2488 | #define EV_MINIMAL 1 |
2048 | #define EV_USE_POLL 0 |
2489 | #define EV_USE_POLL 0 |
2049 | #define EV_MULTIPLICITY 0 |
2490 | #define EV_MULTIPLICITY 0 |
2050 | #define EV_PERIODICS 0 |
2491 | #define EV_PERIODIC_ENABLE 0 |
|
|
2492 | #define EV_STAT_ENABLE 0 |
|
|
2493 | #define EV_FORK_ENABLE 0 |
2051 | #define EV_CONFIG_H <config.h> |
2494 | #define EV_CONFIG_H <config.h> |
|
|
2495 | #define EV_MINPRI 0 |
|
|
2496 | #define EV_MAXPRI 0 |
2052 | |
2497 | |
2053 | #include "ev++.h" |
2498 | #include "ev++.h" |
2054 | |
2499 | |
2055 | And a F<ev_cpp.C> implementation file that contains libev proper and is compiled: |
2500 | And a F<ev_cpp.C> implementation file that contains libev proper and is compiled: |
2056 | |
2501 | |
… | |
… | |
2062 | |
2507 | |
2063 | In this section the complexities of (many of) the algorithms used inside |
2508 | In this section the complexities of (many of) the algorithms used inside |
2064 | libev will be explained. For complexity discussions about backends see the |
2509 | libev will be explained. For complexity discussions about backends see the |
2065 | documentation for C<ev_default_init>. |
2510 | documentation for C<ev_default_init>. |
2066 | |
2511 | |
|
|
2512 | All of the following are about amortised time: If an array needs to be |
|
|
2513 | extended, libev needs to realloc and move the whole array, but this |
|
|
2514 | happens asymptotically never with higher number of elements, so O(1) might |
|
|
2515 | mean it might do a lengthy realloc operation in rare cases, but on average |
|
|
2516 | it is much faster and asymptotically approaches constant time. |
|
|
2517 | |
2067 | =over 4 |
2518 | =over 4 |
2068 | |
2519 | |
2069 | =item Starting and stopping timer/periodic watchers: O(log skipped_other_timers) |
2520 | =item Starting and stopping timer/periodic watchers: O(log skipped_other_timers) |
2070 | |
2521 | |
|
|
2522 | This means that, when you have a watcher that triggers in one hour and |
|
|
2523 | there are 100 watchers that would trigger before that then inserting will |
|
|
2524 | have to skip those 100 watchers. |
|
|
2525 | |
2071 | =item Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers) |
2526 | =item Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers) |
2072 | |
2527 | |
|
|
2528 | That means that for changing a timer costs less than removing/adding them |
|
|
2529 | as only the relative motion in the event queue has to be paid for. |
|
|
2530 | |
2073 | =item Starting io/check/prepare/idle/signal/child watchers: O(1) |
2531 | =item Starting io/check/prepare/idle/signal/child watchers: O(1) |
2074 | |
2532 | |
|
|
2533 | These just add the watcher into an array or at the head of a list. |
2075 | =item Stopping check/prepare/idle watchers: O(1) |
2534 | =item Stopping check/prepare/idle watchers: O(1) |
2076 | |
2535 | |
2077 | =item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16)) |
2536 | =item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE)) |
|
|
2537 | |
|
|
2538 | These watchers are stored in lists then need to be walked to find the |
|
|
2539 | correct watcher to remove. The lists are usually short (you don't usually |
|
|
2540 | have many watchers waiting for the same fd or signal). |
2078 | |
2541 | |
2079 | =item Finding the next timer per loop iteration: O(1) |
2542 | =item Finding the next timer per loop iteration: O(1) |
2080 | |
2543 | |
2081 | =item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd) |
2544 | =item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd) |
2082 | |
2545 | |
|
|
2546 | A change means an I/O watcher gets started or stopped, which requires |
|
|
2547 | libev to recalculate its status (and possibly tell the kernel). |
|
|
2548 | |
2083 | =item Activating one watcher: O(1) |
2549 | =item Activating one watcher: O(1) |
2084 | |
2550 | |
|
|
2551 | =item Priority handling: O(number_of_priorities) |
|
|
2552 | |
|
|
2553 | Priorities are implemented by allocating some space for each |
|
|
2554 | priority. When doing priority-based operations, libev usually has to |
|
|
2555 | linearly search all the priorities. |
|
|
2556 | |
2085 | =back |
2557 | =back |
2086 | |
2558 | |
2087 | |
2559 | |
2088 | =head1 AUTHOR |
2560 | =head1 AUTHOR |
2089 | |
2561 | |