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Comparing libev/ev.pod (file contents):
Revision 1.438 by root, Tue Jan 12 05:52:44 2016 UTC vs.
Revision 1.443 by root, Thu Aug 30 21:51:15 2018 UTC

… …
411make libev check for a fork in each iteration by enabling this flag. 411make libev check for a fork in each iteration by enabling this flag.
412 412
413This works by calling C<getpid ()> on every iteration of the loop, 413This works by calling C<getpid ()> on every iteration of the loop,
414and thus this might slow down your event loop if you do a lot of loop 414and thus this might slow down your event loop if you do a lot of loop
415iterations and little real work, but is usually not noticeable (on my 415iterations and little real work, but is usually not noticeable (on my
416GNU/Linux system for example, C<getpid> is actually a simple 5-insn sequence 416GNU/Linux system for example, C<getpid> is actually a simple 5-insn
417without a system call and thus I<very> fast, but my GNU/Linux system also has 417sequence without a system call and thus I<very> fast, but my GNU/Linux
418C<pthread_atfork> which is even faster). 418system also has C<pthread_atfork> which is even faster). (Update: glibc
419versions 2.25 apparently removed the C<getpid> optimisation again).
419 420
420The big advantage of this flag is that you can forget about fork (and 421The big advantage of this flag is that you can forget about fork (and
421forget about forgetting to tell libev about forking, although you still 422forget about forgetting to tell libev about forking, although you still
422have to ignore C<SIGPIPE>) when you use this flag. 423have to ignore C<SIGPIPE>) when you use this flag.
423 424
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2113 2114
2114=item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat) 2115=item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)
2115 2116
2116=item ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat) 2117=item ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)
2117 2118
2118Configure the timer to trigger after C<after> seconds. If C<repeat> 2119Configure the timer to trigger after C<after> seconds (fractional and
2119is C<0.>, then it will automatically be stopped once the timeout is 2120negative values are supported). If C<repeat> is C<0.>, then it will
2120reached. If it is positive, then the timer will automatically be 2121automatically be stopped once the timeout is reached. If it is positive,
2121configured to trigger again C<repeat> seconds later, again, and again, 2122then the timer will automatically be configured to trigger again C<repeat>
2122until stopped manually. 2123seconds later, again, and again, until stopped manually.
2123 2124
2124The timer itself will do a best-effort at avoiding drift, that is, if 2125The timer itself will do a best-effort at avoiding drift, that is, if
2125you configure a timer to trigger every 10 seconds, then it will normally 2126you configure a timer to trigger every 10 seconds, then it will normally
2126trigger at exactly 10 second intervals. If, however, your program cannot 2127trigger at exactly 10 second intervals. If, however, your program cannot
2127keep up with the timer (because it takes longer than those 10 seconds to 2128keep up with the timer (because it takes longer than those 10 seconds to
… …
3517 3518
3518There are some other functions of possible interest. Described. Here. Now. 3519There are some other functions of possible interest. Described. Here. Now.
3519 3520
3520=over 4 3521=over 4
3521 3522
3522=item ev_once (loop, int fd, int events, ev_tstamp timeout, callback) 3523=item ev_once (loop, int fd, int events, ev_tstamp timeout, callback, arg)
3523 3524
3524This function combines a simple timer and an I/O watcher, calls your 3525This function combines a simple timer and an I/O watcher, calls your
3525callback on whichever event happens first and automatically stops both 3526callback on whichever event happens first and automatically stops both
3526watchers. This is useful if you want to wait for a single event on an fd 3527watchers. This is useful if you want to wait for a single event on an fd
3527or timeout without having to allocate/configure/start/stop/free one or 3528or timeout without having to allocate/configure/start/stop/free one or
… …
4386 ev_vars.h 4387 ev_vars.h
4387 ev_wrap.h 4388 ev_wrap.h
4388 4389
4389 ev_win32.c required on win32 platforms only 4390 ev_win32.c required on win32 platforms only
4390 4391
4391 ev_select.c only when select backend is enabled (which is enabled by default) 4392 ev_select.c only when select backend is enabled
4392 ev_poll.c only when poll backend is enabled (disabled by default) 4393 ev_poll.c only when poll backend is enabled
4393 ev_epoll.c only when the epoll backend is enabled (disabled by default) 4394 ev_epoll.c only when the epoll backend is enabled
4394 ev_kqueue.c only when the kqueue backend is enabled (disabled by default) 4395 ev_kqueue.c only when the kqueue backend is enabled
4395 ev_port.c only when the solaris port backend is enabled (disabled by default) 4396 ev_port.c only when the solaris port backend is enabled
4396 4397
4397F<ev.c> includes the backend files directly when enabled, so you only need 4398F<ev.c> includes the backend files directly when enabled, so you only need
4398to compile this single file. 4399to compile this single file.
4399 4400
4400=head3 LIBEVENT COMPATIBILITY API 4401=head3 LIBEVENT COMPATIBILITY API
… …
5300structure (guaranteed by POSIX but not by ISO C for example), but it also 5301structure (guaranteed by POSIX but not by ISO C for example), but it also
5301assumes that the same (machine) code can be used to call any watcher 5302assumes that the same (machine) code can be used to call any watcher
5302callback: The watcher callbacks have different type signatures, but libev 5303callback: The watcher callbacks have different type signatures, but libev
5303calls them using an C<ev_watcher *> internally. 5304calls them using an C<ev_watcher *> internally.
5304 5305
5306=item null pointers and integer zero are represented by 0 bytes
5307
5308Libev uses C<memset> to initialise structs and arrays to C<0> bytes, and
5309relies on this setting pointers and integers to null.
5310
5305=item pointer accesses must be thread-atomic 5311=item pointer accesses must be thread-atomic
5306 5312
5307Accessing a pointer value must be atomic, it must both be readable and 5313Accessing a pointer value must be atomic, it must both be readable and
5308writable in one piece - this is the case on all current architectures. 5314writable in one piece - this is the case on all current architectures.
5309 5315

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