… | |
… | |
82 | |
82 | |
83 | =head1 WHAT TO READ WHEN IN A HURRY |
83 | =head1 WHAT TO READ WHEN IN A HURRY |
84 | |
84 | |
85 | This manual tries to be very detailed, but unfortunately, this also makes |
85 | This manual tries to be very detailed, but unfortunately, this also makes |
86 | it very long. If you just want to know the basics of libev, I suggest |
86 | it very long. If you just want to know the basics of libev, I suggest |
87 | reading L<ANATOMY OF A WATCHER>, then the L<EXAMPLE PROGRAM> above and |
87 | reading L</ANATOMY OF A WATCHER>, then the L</EXAMPLE PROGRAM> above and |
88 | look up the missing functions in L<GLOBAL FUNCTIONS> and the C<ev_io> and |
88 | look up the missing functions in L</GLOBAL FUNCTIONS> and the C<ev_io> and |
89 | C<ev_timer> sections in L<WATCHER TYPES>. |
89 | C<ev_timer> sections in L</WATCHER TYPES>. |
90 | |
90 | |
91 | =head1 ABOUT LIBEV |
91 | =head1 ABOUT LIBEV |
92 | |
92 | |
93 | Libev is an event loop: you register interest in certain events (such as a |
93 | Libev is an event loop: you register interest in certain events (such as a |
94 | file descriptor being readable or a timeout occurring), and it will manage |
94 | file descriptor being readable or a timeout occurring), and it will manage |
… | |
… | |
764 | |
764 | |
765 | This function is rarely useful, but when some event callback runs for a |
765 | This function is rarely useful, but when some event callback runs for a |
766 | very long time without entering the event loop, updating libev's idea of |
766 | very long time without entering the event loop, updating libev's idea of |
767 | the current time is a good idea. |
767 | the current time is a good idea. |
768 | |
768 | |
769 | See also L<The special problem of time updates> in the C<ev_timer> section. |
769 | See also L</The special problem of time updates> in the C<ev_timer> section. |
770 | |
770 | |
771 | =item ev_suspend (loop) |
771 | =item ev_suspend (loop) |
772 | |
772 | |
773 | =item ev_resume (loop) |
773 | =item ev_resume (loop) |
774 | |
774 | |
… | |
… | |
1318 | |
1318 | |
1319 | =item callback ev_cb (ev_TYPE *watcher) |
1319 | =item callback ev_cb (ev_TYPE *watcher) |
1320 | |
1320 | |
1321 | Returns the callback currently set on the watcher. |
1321 | Returns the callback currently set on the watcher. |
1322 | |
1322 | |
1323 | =item ev_cb_set (ev_TYPE *watcher, callback) |
1323 | =item ev_set_cb (ev_TYPE *watcher, callback) |
1324 | |
1324 | |
1325 | Change the callback. You can change the callback at virtually any time |
1325 | Change the callback. You can change the callback at virtually any time |
1326 | (modulo threads). |
1326 | (modulo threads). |
1327 | |
1327 | |
1328 | =item ev_set_priority (ev_TYPE *watcher, int priority) |
1328 | =item ev_set_priority (ev_TYPE *watcher, int priority) |
… | |
… | |
1346 | or might not have been clamped to the valid range. |
1346 | or might not have been clamped to the valid range. |
1347 | |
1347 | |
1348 | The default priority used by watchers when no priority has been set is |
1348 | The default priority used by watchers when no priority has been set is |
1349 | always C<0>, which is supposed to not be too high and not be too low :). |
1349 | always C<0>, which is supposed to not be too high and not be too low :). |
1350 | |
1350 | |
1351 | See L<WATCHER PRIORITY MODELS>, below, for a more thorough treatment of |
1351 | See L</WATCHER PRIORITY MODELS>, below, for a more thorough treatment of |
1352 | priorities. |
1352 | priorities. |
1353 | |
1353 | |
1354 | =item ev_invoke (loop, ev_TYPE *watcher, int revents) |
1354 | =item ev_invoke (loop, ev_TYPE *watcher, int revents) |
1355 | |
1355 | |
1356 | Invoke the C<watcher> with the given C<loop> and C<revents>. Neither |
1356 | Invoke the C<watcher> with the given C<loop> and C<revents>. Neither |
… | |
… | |
1381 | See also C<ev_feed_fd_event> and C<ev_feed_signal_event> for related |
1381 | See also C<ev_feed_fd_event> and C<ev_feed_signal_event> for related |
1382 | functions that do not need a watcher. |
1382 | functions that do not need a watcher. |
1383 | |
1383 | |
1384 | =back |
1384 | =back |
1385 | |
1385 | |
1386 | See also the L<ASSOCIATING CUSTOM DATA WITH A WATCHER> and L<BUILDING YOUR |
1386 | See also the L</ASSOCIATING CUSTOM DATA WITH A WATCHER> and L</BUILDING YOUR |
1387 | OWN COMPOSITE WATCHERS> idioms. |
1387 | OWN COMPOSITE WATCHERS> idioms. |
1388 | |
1388 | |
1389 | =head2 WATCHER STATES |
1389 | =head2 WATCHER STATES |
1390 | |
1390 | |
1391 | There are various watcher states mentioned throughout this manual - |
1391 | There are various watcher states mentioned throughout this manual - |
… | |
… | |
2136 | =item If the timer is repeating, make the C<repeat> value the new timeout |
2136 | =item If the timer is repeating, make the C<repeat> value the new timeout |
2137 | and start the timer, if necessary. |
2137 | and start the timer, if necessary. |
2138 | |
2138 | |
2139 | =back |
2139 | =back |
2140 | |
2140 | |
2141 | This sounds a bit complicated, see L<Be smart about timeouts>, above, for a |
2141 | This sounds a bit complicated, see L</Be smart about timeouts>, above, for a |
2142 | usage example. |
2142 | usage example. |
2143 | |
2143 | |
2144 | =item ev_tstamp ev_timer_remaining (loop, ev_timer *) |
2144 | =item ev_tstamp ev_timer_remaining (loop, ev_timer *) |
2145 | |
2145 | |
2146 | Returns the remaining time until a timer fires. If the timer is active, |
2146 | Returns the remaining time until a timer fires. If the timer is active, |
… | |
… | |
2858 | |
2858 | |
2859 | This mode of operation can be useful together with an C<ev_check> watcher, |
2859 | This mode of operation can be useful together with an C<ev_check> watcher, |
2860 | to do something on each event loop iteration - for example to balance load |
2860 | to do something on each event loop iteration - for example to balance load |
2861 | between different connections. |
2861 | between different connections. |
2862 | |
2862 | |
2863 | See L<Abusing an C<ev_check> watcher for its side-effect> for a longer |
2863 | See L</Abusing an ev_check watcher for its side-effect> for a longer |
2864 | example. |
2864 | example. |
2865 | |
2865 | |
2866 | =head3 Watcher-Specific Functions and Data Members |
2866 | =head3 Watcher-Specific Functions and Data Members |
2867 | |
2867 | |
2868 | =over 4 |
2868 | =over 4 |
… | |
… | |
2881 | callback, free it. Also, use no error checking, as usual. |
2881 | callback, free it. Also, use no error checking, as usual. |
2882 | |
2882 | |
2883 | static void |
2883 | static void |
2884 | idle_cb (struct ev_loop *loop, ev_idle *w, int revents) |
2884 | idle_cb (struct ev_loop *loop, ev_idle *w, int revents) |
2885 | { |
2885 | { |
|
|
2886 | // stop the watcher |
|
|
2887 | ev_idle_stop (loop, w); |
|
|
2888 | |
|
|
2889 | // now we can free it |
2886 | free (w); |
2890 | free (w); |
|
|
2891 | |
2887 | // now do something you wanted to do when the program has |
2892 | // now do something you wanted to do when the program has |
2888 | // no longer anything immediate to do. |
2893 | // no longer anything immediate to do. |
2889 | } |
2894 | } |
2890 | |
2895 | |
2891 | ev_idle *idle_watcher = malloc (sizeof (ev_idle)); |
2896 | ev_idle *idle_watcher = malloc (sizeof (ev_idle)); |
… | |
… | |
3870 | called): |
3875 | called): |
3871 | |
3876 | |
3872 | void |
3877 | void |
3873 | wait_for_event (ev_watcher *w) |
3878 | wait_for_event (ev_watcher *w) |
3874 | { |
3879 | { |
3875 | ev_cb_set (w) = current_coro; |
3880 | ev_set_cb (w, current_coro); |
3876 | switch_to (libev_coro); |
3881 | switch_to (libev_coro); |
3877 | } |
3882 | } |
3878 | |
3883 | |
3879 | That basically suspends the coroutine inside C<wait_for_event> and |
3884 | That basically suspends the coroutine inside C<wait_for_event> and |
3880 | continues the libev coroutine, which, when appropriate, switches back to |
3885 | continues the libev coroutine, which, when appropriate, switches back to |
… | |
… | |
3883 | You can do similar tricks if you have, say, threads with an event queue - |
3888 | You can do similar tricks if you have, say, threads with an event queue - |
3884 | instead of storing a coroutine, you store the queue object and instead of |
3889 | instead of storing a coroutine, you store the queue object and instead of |
3885 | switching to a coroutine, you push the watcher onto the queue and notify |
3890 | switching to a coroutine, you push the watcher onto the queue and notify |
3886 | any waiters. |
3891 | any waiters. |
3887 | |
3892 | |
3888 | To embed libev, see L<EMBEDDING>, but in short, it's easiest to create two |
3893 | To embed libev, see L</EMBEDDING>, but in short, it's easiest to create two |
3889 | files, F<my_ev.h> and F<my_ev.c> that include the respective libev files: |
3894 | files, F<my_ev.h> and F<my_ev.c> that include the respective libev files: |
3890 | |
3895 | |
3891 | // my_ev.h |
3896 | // my_ev.h |
3892 | #define EV_CB_DECLARE(type) struct my_coro *cb; |
3897 | #define EV_CB_DECLARE(type) struct my_coro *cb; |
3893 | #define EV_CB_INVOKE(watcher) switch_to ((watcher)->cb); |
3898 | #define EV_CB_INVOKE(watcher) switch_to ((watcher)->cb); |
… | |
… | |
3945 | libev sources can be compiled as C++. Therefore, code that uses the C API |
3950 | libev sources can be compiled as C++. Therefore, code that uses the C API |
3946 | will work fine. |
3951 | will work fine. |
3947 | |
3952 | |
3948 | Proper exception specifications might have to be added to callbacks passed |
3953 | Proper exception specifications might have to be added to callbacks passed |
3949 | to libev: exceptions may be thrown only from watcher callbacks, all |
3954 | to libev: exceptions may be thrown only from watcher callbacks, all |
3950 | other callbacks (allocator, syserr, loop acquire/release and periodioc |
3955 | other callbacks (allocator, syserr, loop acquire/release and periodic |
3951 | reschedule callbacks) must not throw exceptions, and might need a C<throw |
3956 | reschedule callbacks) must not throw exceptions, and might need a C<throw |
3952 | ()> specification. If you have code that needs to be compiled as both C |
3957 | ()> specification. If you have code that needs to be compiled as both C |
3953 | and C++ you can use the C<EV_THROW> macro for this: |
3958 | and C++ you can use the C<EV_THROW> macro for this: |
3954 | |
3959 | |
3955 | static void |
3960 | static void |
… | |
… | |
4116 | Associates a different C<struct ev_loop> with this watcher. You can only |
4121 | Associates a different C<struct ev_loop> with this watcher. You can only |
4117 | do this when the watcher is inactive (and not pending either). |
4122 | do this when the watcher is inactive (and not pending either). |
4118 | |
4123 | |
4119 | =item w->set ([arguments]) |
4124 | =item w->set ([arguments]) |
4120 | |
4125 | |
4121 | Basically the same as C<ev_TYPE_set>, with the same arguments. Either this |
4126 | Basically the same as C<ev_TYPE_set> (except for C<ev::embed> watchers>), |
4122 | method or a suitable start method must be called at least once. Unlike the |
4127 | with the same arguments. Either this method or a suitable start method |
4123 | C counterpart, an active watcher gets automatically stopped and restarted |
4128 | must be called at least once. Unlike the C counterpart, an active watcher |
4124 | when reconfiguring it with this method. |
4129 | gets automatically stopped and restarted when reconfiguring it with this |
|
|
4130 | method. |
|
|
4131 | |
|
|
4132 | For C<ev::embed> watchers this method is called C<set_embed>, to avoid |
|
|
4133 | clashing with the C<set (loop)> method. |
4125 | |
4134 | |
4126 | =item w->start () |
4135 | =item w->start () |
4127 | |
4136 | |
4128 | Starts the watcher. Note that there is no C<loop> argument, as the |
4137 | Starts the watcher. Note that there is no C<loop> argument, as the |
4129 | constructor already stores the event loop. |
4138 | constructor already stores the event loop. |
… | |
… | |
4232 | =item Lua |
4241 | =item Lua |
4233 | |
4242 | |
4234 | Brian Maher has written a partial interface to libev for lua (at the |
4243 | Brian Maher has written a partial interface to libev for lua (at the |
4235 | time of this writing, only C<ev_io> and C<ev_timer>), to be found at |
4244 | time of this writing, only C<ev_io> and C<ev_timer>), to be found at |
4236 | L<http://github.com/brimworks/lua-ev>. |
4245 | L<http://github.com/brimworks/lua-ev>. |
|
|
4246 | |
|
|
4247 | =item Javascript |
|
|
4248 | |
|
|
4249 | Node.js (L<http://nodejs.org>) uses libev as the underlying event library. |
|
|
4250 | |
|
|
4251 | =item Others |
|
|
4252 | |
|
|
4253 | There are others, and I stopped counting. |
4237 | |
4254 | |
4238 | =back |
4255 | =back |
4239 | |
4256 | |
4240 | |
4257 | |
4241 | =head1 MACRO MAGIC |
4258 | =head1 MACRO MAGIC |
… | |
… | |
4540 | |
4557 | |
4541 | If programs implement their own fd to handle mapping on win32, then this |
4558 | If programs implement their own fd to handle mapping on win32, then this |
4542 | macro can be used to override the C<close> function, useful to unregister |
4559 | macro can be used to override the C<close> function, useful to unregister |
4543 | file descriptors again. Note that the replacement function has to close |
4560 | file descriptors again. Note that the replacement function has to close |
4544 | the underlying OS handle. |
4561 | the underlying OS handle. |
|
|
4562 | |
|
|
4563 | =item EV_USE_WSASOCKET |
|
|
4564 | |
|
|
4565 | If defined to be C<1>, libev will use C<WSASocket> to create its internal |
|
|
4566 | communication socket, which works better in some environments. Otherwise, |
|
|
4567 | the normal C<socket> function will be used, which works better in other |
|
|
4568 | environments. |
4545 | |
4569 | |
4546 | =item EV_USE_POLL |
4570 | =item EV_USE_POLL |
4547 | |
4571 | |
4548 | If defined to be C<1>, libev will compile in support for the C<poll>(2) |
4572 | If defined to be C<1>, libev will compile in support for the C<poll>(2) |
4549 | backend. Otherwise it will be enabled on non-win32 platforms. It |
4573 | backend. Otherwise it will be enabled on non-win32 platforms. It |
… | |
… | |
4601 | above. This reduces dependencies and makes libev faster. |
4625 | above. This reduces dependencies and makes libev faster. |
4602 | |
4626 | |
4603 | =item EV_ATOMIC_T |
4627 | =item EV_ATOMIC_T |
4604 | |
4628 | |
4605 | Libev requires an integer type (suitable for storing C<0> or C<1>) whose |
4629 | Libev requires an integer type (suitable for storing C<0> or C<1>) whose |
4606 | access is atomic and serialised with respect to other threads or signal |
4630 | access is atomic with respect to other threads or signal contexts. No |
4607 | contexts. No such type is easily found in the C language, so you can |
4631 | such type is easily found in the C language, so you can provide your own |
4608 | provide your own type that you know is safe for your purposes. It is used |
4632 | type that you know is safe for your purposes. It is used both for signal |
4609 | both for signal handler "locking" as well as for signal and thread safety |
4633 | handler "locking" as well as for signal and thread safety in C<ev_async> |
4610 | in C<ev_async> watchers. |
4634 | watchers. |
4611 | |
4635 | |
4612 | In the absence of this define, libev will use C<sig_atomic_t volatile> |
4636 | In the absence of this define, libev will use C<sig_atomic_t volatile> |
4613 | (from F<signal.h>), which is usually good enough on most platforms, |
4637 | (from F<signal.h>), which is usually good enough on most platforms. |
4614 | although strictly speaking using a type that also implies a memory fence |
|
|
4615 | is required. |
|
|
4616 | |
4638 | |
4617 | =item EV_H (h) |
4639 | =item EV_H (h) |
4618 | |
4640 | |
4619 | The name of the F<ev.h> header file used to include it. The default if |
4641 | The name of the F<ev.h> header file used to include it. The default if |
4620 | undefined is C<"ev.h"> in F<event.h>, F<ev.c> and F<ev++.h>. This can be |
4642 | undefined is C<"ev.h"> in F<event.h>, F<ev.c> and F<ev++.h>. This can be |
… | |
… | |
4988 | default loop and triggering an C<ev_async> watcher from the default loop |
5010 | default loop and triggering an C<ev_async> watcher from the default loop |
4989 | watcher callback into the event loop interested in the signal. |
5011 | watcher callback into the event loop interested in the signal. |
4990 | |
5012 | |
4991 | =back |
5013 | =back |
4992 | |
5014 | |
4993 | See also L<THREAD LOCKING EXAMPLE>. |
5015 | See also L</THREAD LOCKING EXAMPLE>. |
4994 | |
5016 | |
4995 | =head3 COROUTINES |
5017 | =head3 COROUTINES |
4996 | |
5018 | |
4997 | Libev is very accommodating to coroutines ("cooperative threads"): |
5019 | Libev is very accommodating to coroutines ("cooperative threads"): |
4998 | libev fully supports nesting calls to its functions from different |
5020 | libev fully supports nesting calls to its functions from different |
… | |
… | |
5404 | =over 4 |
5426 | =over 4 |
5405 | |
5427 | |
5406 | =item C<EV_COMPAT3> backwards compatibility mechanism |
5428 | =item C<EV_COMPAT3> backwards compatibility mechanism |
5407 | |
5429 | |
5408 | The backward compatibility mechanism can be controlled by |
5430 | The backward compatibility mechanism can be controlled by |
5409 | C<EV_COMPAT3>. See L<PREPROCESSOR SYMBOLS/MACROS> in the L<EMBEDDING> |
5431 | C<EV_COMPAT3>. See L</PREPROCESSOR SYMBOLS/MACROS> in the L</EMBEDDING> |
5410 | section. |
5432 | section. |
5411 | |
5433 | |
5412 | =item C<ev_default_destroy> and C<ev_default_fork> have been removed |
5434 | =item C<ev_default_destroy> and C<ev_default_fork> have been removed |
5413 | |
5435 | |
5414 | These calls can be replaced easily by their C<ev_loop_xxx> counterparts: |
5436 | These calls can be replaced easily by their C<ev_loop_xxx> counterparts: |
… | |
… | |
5457 | =over 4 |
5479 | =over 4 |
5458 | |
5480 | |
5459 | =item active |
5481 | =item active |
5460 | |
5482 | |
5461 | A watcher is active as long as it has been started and not yet stopped. |
5483 | A watcher is active as long as it has been started and not yet stopped. |
5462 | See L<WATCHER STATES> for details. |
5484 | See L</WATCHER STATES> for details. |
5463 | |
5485 | |
5464 | =item application |
5486 | =item application |
5465 | |
5487 | |
5466 | In this document, an application is whatever is using libev. |
5488 | In this document, an application is whatever is using libev. |
5467 | |
5489 | |
… | |
… | |
5503 | watchers and events. |
5525 | watchers and events. |
5504 | |
5526 | |
5505 | =item pending |
5527 | =item pending |
5506 | |
5528 | |
5507 | A watcher is pending as soon as the corresponding event has been |
5529 | A watcher is pending as soon as the corresponding event has been |
5508 | detected. See L<WATCHER STATES> for details. |
5530 | detected. See L</WATCHER STATES> for details. |
5509 | |
5531 | |
5510 | =item real time |
5532 | =item real time |
5511 | |
5533 | |
5512 | The physical time that is observed. It is apparently strictly monotonic :) |
5534 | The physical time that is observed. It is apparently strictly monotonic :) |
5513 | |
5535 | |