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Comparing libev/ev.3 (file contents):
Revision 1.103 by root, Fri May 1 17:23:34 2015 UTC vs.
Revision 1.108 by root, Sat Jul 28 04:15:15 2018 UTC

1.\" Automatically generated by Pod::Man 2.28 (Pod::Simple 3.28) 1.\" Automatically generated by Pod::Man 2.28 (Pod::Simple 3.29)
2.\" 2.\"
3.\" Standard preamble: 3.\" Standard preamble:
4.\" ======================================================================== 4.\" ========================================================================
5.de Sp \" Vertical space (when we can't use .PP) 5.de Sp \" Vertical space (when we can't use .PP)
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131.\} 131.\}
132.rm #[ #] #H #V #F C 132.rm #[ #] #H #V #F C
133.\" ======================================================================== 133.\" ========================================================================
134.\" 134.\"
135.IX Title "LIBEV 3" 135.IX Title "LIBEV 3"
136.TH LIBEV 3 "2015-05-01" "libev-4.19" "libev - high performance full featured event loop" 136.TH LIBEV 3 "2017-11-14" "libev-4.24" "libev - high performance full featured event loop"
137.\" For nroff, turn off justification. Always turn off hyphenation; it makes 137.\" For nroff, turn off justification. Always turn off hyphenation; it makes
138.\" way too many mistakes in technical documents. 138.\" way too many mistakes in technical documents.
139.if n .ad l 139.if n .ad l
140.nh 140.nh
141.SH "NAME" 141.SH "NAME"
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536make libev check for a fork in each iteration by enabling this flag. 536make libev check for a fork in each iteration by enabling this flag.
537.Sp 537.Sp
538This works by calling \f(CW\*(C`getpid ()\*(C'\fR on every iteration of the loop, 538This works by calling \f(CW\*(C`getpid ()\*(C'\fR on every iteration of the loop,
539and thus this might slow down your event loop if you do a lot of loop 539and thus this might slow down your event loop if you do a lot of loop
540iterations and little real work, but is usually not noticeable (on my 540iterations and little real work, but is usually not noticeable (on my
541GNU/Linux system for example, \f(CW\*(C`getpid\*(C'\fR is actually a simple 5\-insn sequence 541GNU/Linux system for example, \f(CW\*(C`getpid\*(C'\fR is actually a simple 5\-insn
542without a system call and thus \fIvery\fR fast, but my GNU/Linux system also has 542sequence without a system call and thus \fIvery\fR fast, but my GNU/Linux
543\&\f(CW\*(C`pthread_atfork\*(C'\fR which is even faster). 543system also has \f(CW\*(C`pthread_atfork\*(C'\fR which is even faster). (Update: glibc
544versions 2.25 apparently removed the \f(CW\*(C`getpid\*(C'\fR optimisation again).
544.Sp 545.Sp
545The big advantage of this flag is that you can forget about fork (and 546The big advantage of this flag is that you can forget about fork (and
546forget about forgetting to tell libev about forking) when you use this 547forget about forgetting to tell libev about forking, although you still
547flag. 548have to ignore \f(CW\*(C`SIGPIPE\*(C'\fR) when you use this flag.
548.Sp 549.Sp
549This flag setting cannot be overridden or specified in the \f(CW\*(C`LIBEV_FLAGS\*(C'\fR 550This flag setting cannot be overridden or specified in the \f(CW\*(C`LIBEV_FLAGS\*(C'\fR
550environment variable. 551environment variable.
551.ie n .IP """EVFLAG_NOINOTIFY""" 4 552.ie n .IP """EVFLAG_NOINOTIFY""" 4
552.el .IP "\f(CWEVFLAG_NOINOTIFY\fR" 4 553.el .IP "\f(CWEVFLAG_NOINOTIFY\fR" 4
… …
816to reinitialise the kernel state for backends that have one. Despite 817to reinitialise the kernel state for backends that have one. Despite
817the name, you can call it anytime you are allowed to start or stop 818the name, you can call it anytime you are allowed to start or stop
818watchers (except inside an \f(CW\*(C`ev_prepare\*(C'\fR callback), but it makes most 819watchers (except inside an \f(CW\*(C`ev_prepare\*(C'\fR callback), but it makes most
819sense after forking, in the child process. You \fImust\fR call it (or use 820sense after forking, in the child process. You \fImust\fR call it (or use
820\&\f(CW\*(C`EVFLAG_FORKCHECK\*(C'\fR) in the child before resuming or calling \f(CW\*(C`ev_run\*(C'\fR. 821\&\f(CW\*(C`EVFLAG_FORKCHECK\*(C'\fR) in the child before resuming or calling \f(CW\*(C`ev_run\*(C'\fR.
822.Sp
823In addition, if you want to reuse a loop (via this function or
824\&\f(CW\*(C`EVFLAG_FORKCHECK\*(C'\fR), you \fIalso\fR have to ignore \f(CW\*(C`SIGPIPE\*(C'\fR.
821.Sp 825.Sp
822Again, you \fIhave\fR to call it on \fIany\fR loop that you want to re-use after 826Again, you \fIhave\fR to call it on \fIany\fR loop that you want to re-use after
823a fork, \fIeven if you do not plan to use the loop in the parent\fR. This is 827a fork, \fIeven if you do not plan to use the loop in the parent\fR. This is
824because some kernel interfaces *cough* \fIkqueue\fR *cough* do funny things 828because some kernel interfaces *cough* \fIkqueue\fR *cough* do funny things
825during fork. 829during fork.
… …
2343Periodic watchers are also timers of a kind, but they are very versatile 2347Periodic watchers are also timers of a kind, but they are very versatile
2344(and unfortunately a bit complex). 2348(and unfortunately a bit complex).
2345.PP 2349.PP
2346Unlike \f(CW\*(C`ev_timer\*(C'\fR, periodic watchers are not based on real time (or 2350Unlike \f(CW\*(C`ev_timer\*(C'\fR, periodic watchers are not based on real time (or
2347relative time, the physical time that passes) but on wall clock time 2351relative time, the physical time that passes) but on wall clock time
2348(absolute time, the thing you can read on your calender or clock). The 2352(absolute time, the thing you can read on your calendar or clock). The
2349difference is that wall clock time can run faster or slower than real 2353difference is that wall clock time can run faster or slower than real
2350time, and time jumps are not uncommon (e.g. when you adjust your 2354time, and time jumps are not uncommon (e.g. when you adjust your
2351wrist-watch). 2355wrist-watch).
2352.PP 2356.PP
2353You can tell a periodic watcher to trigger after some specific point 2357You can tell a periodic watcher to trigger after some specific point
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4518\& ev_vars.h 4522\& ev_vars.h
4519\& ev_wrap.h 4523\& ev_wrap.h
4520\& 4524\&
4521\& ev_win32.c required on win32 platforms only 4525\& ev_win32.c required on win32 platforms only
4522\& 4526\&
4523\& ev_select.c only when select backend is enabled (which is enabled by default) 4527\& ev_select.c only when select backend is enabled
4524\& ev_poll.c only when poll backend is enabled (disabled by default) 4528\& ev_poll.c only when poll backend is enabled
4525\& ev_epoll.c only when the epoll backend is enabled (disabled by default) 4529\& ev_epoll.c only when the epoll backend is enabled
4526\& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) 4530\& ev_kqueue.c only when the kqueue backend is enabled
4527\& ev_port.c only when the solaris port backend is enabled (disabled by default) 4531\& ev_port.c only when the solaris port backend is enabled
4528.Ve 4532.Ve
4529.PP 4533.PP
4530\&\fIev.c\fR includes the backend files directly when enabled, so you only need 4534\&\fIev.c\fR includes the backend files directly when enabled, so you only need
4531to compile this single file. 4535to compile this single file.
4532.PP 4536.PP
… …
5409Libev assumes not only that all watcher pointers have the same internal 5413Libev assumes not only that all watcher pointers have the same internal
5410structure (guaranteed by \s-1POSIX\s0 but not by \s-1ISO C\s0 for example), but it also 5414structure (guaranteed by \s-1POSIX\s0 but not by \s-1ISO C\s0 for example), but it also
5411assumes that the same (machine) code can be used to call any watcher 5415assumes that the same (machine) code can be used to call any watcher
5412callback: The watcher callbacks have different type signatures, but libev 5416callback: The watcher callbacks have different type signatures, but libev
5413calls them using an \f(CW\*(C`ev_watcher *\*(C'\fR internally. 5417calls them using an \f(CW\*(C`ev_watcher *\*(C'\fR internally.
5418.IP "null pointers and integer zero are represented by 0 bytes" 4
5419.IX Item "null pointers and integer zero are represented by 0 bytes"
5420Libev uses \f(CW\*(C`memset\*(C'\fR to initialise structs and arrays to \f(CW0\fR bytes, and
5421relies on this setting pointers and integers to null.
5414.IP "pointer accesses must be thread-atomic" 4 5422.IP "pointer accesses must be thread-atomic" 4
5415.IX Item "pointer accesses must be thread-atomic" 5423.IX Item "pointer accesses must be thread-atomic"
5416Accessing a pointer value must be atomic, it must both be readable and 5424Accessing a pointer value must be atomic, it must both be readable and
5417writable in one piece \- this is the case on all current architectures. 5425writable in one piece \- this is the case on all current architectures.
5418.ie n .IP """sig_atomic_t volatile"" must be thread-atomic as well" 4 5426.ie n .IP """sig_atomic_t volatile"" must be thread-atomic as well" 4

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