X-Git-Url: https://git.llucax.com/software/libev.git/blobdiff_plain/4422091b9b8967efdcfea8f650321595a8d95a98..924ae10c0376cdb4b581d30f7b8a258b6b9e4853:/ev.3

diff --git a/ev.3 b/ev.3
index 4cddbe3..a2e0946 100644
--- a/ev.3
+++ b/ev.3
@@ -137,6 +137,65 @@ libev \- a high performance full\-featured event loop written in C
 .Vb 1
 \&  #include <ev.h>
 .Ve
+.SH "EXAMPLE PROGRAM"
+.IX Header "EXAMPLE PROGRAM"
+.Vb 1
+\&  #include <ev.h>
+.Ve
+.PP
+.Vb 2
+\&  ev_io stdin_watcher;
+\&  ev_timer timeout_watcher;
+.Ve
+.PP
+.Vb 8
+\&  /* called when data readable on stdin */
+\&  static void
+\&  stdin_cb (EV_P_ struct ev_io *w, int revents)
+\&  {
+\&    /* puts ("stdin ready"); */
+\&    ev_io_stop (EV_A_ w); /* just a syntax example */
+\&    ev_unloop (EV_A_ EVUNLOOP_ALL); /* leave all loop calls */
+\&  }
+.Ve
+.PP
+.Vb 6
+\&  static void
+\&  timeout_cb (EV_P_ struct ev_timer *w, int revents)
+\&  {
+\&    /* puts ("timeout"); */
+\&    ev_unloop (EV_A_ EVUNLOOP_ONE); /* leave one loop call */
+\&  }
+.Ve
+.PP
+.Vb 4
+\&  int
+\&  main (void)
+\&  {
+\&    struct ev_loop *loop = ev_default_loop (0);
+.Ve
+.PP
+.Vb 3
+\&    /* initialise an io watcher, then start it */
+\&    ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ);
+\&    ev_io_start (loop, &stdin_watcher);
+.Ve
+.PP
+.Vb 3
+\&    /* simple non-repeating 5.5 second timeout */
+\&    ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);
+\&    ev_timer_start (loop, &timeout_watcher);
+.Ve
+.PP
+.Vb 2
+\&    /* loop till timeout or data ready */
+\&    ev_loop (loop, 0);
+.Ve
+.PP
+.Vb 2
+\&    return 0;
+\&  }
+.Ve
 .SH "DESCRIPTION"
 .IX Header "DESCRIPTION"
 Libev is an event loop: you register interest in certain events (such as a
@@ -153,22 +212,27 @@ details of the event, and then hand it over to libev by \fIstarting\fR the
 watcher.
 .SH "FEATURES"
 .IX Header "FEATURES"
-Libev supports select, poll, the linux-specific epoll and the bsd-specific
-kqueue mechanisms for file descriptor events, relative timers, absolute
-timers with customised rescheduling, signal events, process status change
-events (related to \s-1SIGCHLD\s0), and event watchers dealing with the event
-loop mechanism itself (idle, prepare and check watchers). It also is quite
-fast (see this benchmark comparing
-it to libevent for example).
+Libev supports \f(CW\*(C`select\*(C'\fR, \f(CW\*(C`poll\*(C'\fR, the linux-specific \f(CW\*(C`epoll\*(C'\fR, the
+bsd-specific \f(CW\*(C`kqueue\*(C'\fR and the solaris-specific event port mechanisms
+for file descriptor events (\f(CW\*(C`ev_io\*(C'\fR), relative timers (\f(CW\*(C`ev_timer\*(C'\fR),
+absolute timers with customised rescheduling (\f(CW\*(C`ev_periodic\*(C'\fR), synchronous
+signals (\f(CW\*(C`ev_signal\*(C'\fR), process status change events (\f(CW\*(C`ev_child\*(C'\fR), and
+event watchers dealing with the event loop mechanism itself (\f(CW\*(C`ev_idle\*(C'\fR,
+\&\f(CW\*(C`ev_embed\*(C'\fR, \f(CW\*(C`ev_prepare\*(C'\fR and \f(CW\*(C`ev_check\*(C'\fR watchers) as well as
+file watchers (\f(CW\*(C`ev_stat\*(C'\fR) and even limited support for fork events
+(\f(CW\*(C`ev_fork\*(C'\fR).
+.PP
+It also is quite fast (see this
+benchmark comparing it to libevent
+for example).
 .SH "CONVENTIONS"
 .IX Header "CONVENTIONS"
-Libev is very configurable. In this manual the default configuration
-will be described, which supports multiple event loops. For more info
-about various configuration options please have a look at the file
-\&\fI\s-1README\s0.embed\fR in the libev distribution. If libev was configured without
-support for multiple event loops, then all functions taking an initial
-argument of name \f(CW\*(C`loop\*(C'\fR (which is always of type \f(CW\*(C`struct ev_loop *\*(C'\fR)
-will not have this argument.
+Libev is very configurable. In this manual the default configuration will
+be described, which supports multiple event loops. For more info about
+various configuration options please have a look at \fB\s-1EMBED\s0\fR section in
+this manual. If libev was configured without support for multiple event
+loops, then all functions taking an initial argument of name \f(CW\*(C`loop\*(C'\fR
+(which is always of type \f(CW\*(C`struct ev_loop *\*(C'\fR) will not have this argument.
 .SH "TIME REPRESENTATION"
 .IX Header "TIME REPRESENTATION"
 Libev represents time as a single floating point number, representing the
@@ -203,8 +267,8 @@ as this indicates an incompatible change.  Minor versions are usually
 compatible to older versions, so a larger minor version alone is usually
 not a problem.
 .Sp
-Example: make sure we haven't accidentally been linked against the wrong
-version:
+Example: Make sure we haven't accidentally been linked against the wrong
+version.
 .Sp
 .Vb 3
 \&  assert (("libev version mismatch",
@@ -242,24 +306,24 @@ might be supported on the current system, you would need to look at
 recommended ones.
 .Sp
 See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info.
-.IP "ev_set_allocator (void *(*cb)(void *ptr, long size))" 4
-.IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))"
-Sets the allocation function to use (the prototype is similar to the
-realloc C function, the semantics are identical). It is used to allocate
-and free memory (no surprises here). If it returns zero when memory
-needs to be allocated, the library might abort or take some potentially
-destructive action. The default is your system realloc function.
+.IP "ev_set_allocator (void *(*cb)(void *ptr, size_t size))" 4
+.IX Item "ev_set_allocator (void *(*cb)(void *ptr, size_t size))"
+Sets the allocation function to use (the prototype and semantics are
+identical to the realloc C function). It is used to allocate and free
+memory (no surprises here). If it returns zero when memory needs to be
+allocated, the library might abort or take some potentially destructive
+action. The default is your system realloc function.
 .Sp
 You could override this function in high-availability programs to, say,
 free some memory if it cannot allocate memory, to use a special allocator,
 or even to sleep a while and retry until some memory is available.
 .Sp
-Example: replace the libev allocator with one that waits a bit and then
-retries: better than mine).
+Example: Replace the libev allocator with one that waits a bit and then
+retries).
 .Sp
 .Vb 6
 \&   static void *
-\&   persistent_realloc (void *ptr, long size)
+\&   persistent_realloc (void *ptr, size_t size)
 \&   {
 \&     for (;;)
 \&       {
@@ -291,7 +355,7 @@ matter what, when it returns. That is, libev will generally retry the
 requested operation, or, if the condition doesn't go away, do bad stuff
 (such as abort).
 .Sp
-Example: do the same thing as libev does internally:
+Example: This is basically the same thing that libev does internally, too.
 .Sp
 .Vb 6
 \&   static void
@@ -450,7 +514,7 @@ always distinct from the default loop. Unlike the default loop, it cannot
 handle signal and child watchers, and attempts to do so will be greeted by
 undefined behaviour (or a failed assertion if assertions are enabled).
 .Sp
-Example: try to create a event loop that uses epoll and nothing else.
+Example: Try to create a event loop that uses epoll and nothing else.
 .Sp
 .Vb 3
 \&  struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);
@@ -558,7 +622,7 @@ Here are the gory details of what \f(CW\*(C`ev_loop\*(C'\fR does:
 \&     were used, return, otherwise continue with step *.
 .Ve
 .Sp
-Example: queue some jobs and then loop until no events are outsanding
+Example: Queue some jobs and then loop until no events are outsanding
 anymore.
 .Sp
 .Vb 4
@@ -590,21 +654,21 @@ no event watchers registered by it are active. It is also an excellent
 way to do this for generic recurring timers or from within third-party
 libraries. Just remember to \fIunref after start\fR and \fIref before stop\fR.
 .Sp
-Example: create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR
+Example: Create a signal watcher, but keep it from keeping \f(CW\*(C`ev_loop\*(C'\fR
 running when nothing else is active.
 .Sp
 .Vb 4
-\&  struct dv_signal exitsig;
+\&  struct ev_signal exitsig;
 \&  ev_signal_init (&exitsig, sig_cb, SIGINT);
-\&  ev_signal_start (myloop, &exitsig);
-\&  evf_unref (myloop);
+\&  ev_signal_start (loop, &exitsig);
+\&  evf_unref (loop);
 .Ve
 .Sp
-Example: for some weird reason, unregister the above signal handler again.
+Example: For some weird reason, unregister the above signal handler again.
 .Sp
 .Vb 2
-\&  ev_ref (myloop);
-\&  ev_signal_stop (myloop, &exitsig);
+\&  ev_ref (loop);
+\&  ev_signal_stop (loop, &exitsig);
 .Ve
 .SH "ANATOMY OF A WATCHER"
 .IX Header "ANATOMY OF A WATCHER"
@@ -709,6 +773,15 @@ received events. Callbacks of both watcher types can start and stop as
 many watchers as they want, and all of them will be taken into account
 (for example, a \f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep
 \&\f(CW\*(C`ev_loop\*(C'\fR from blocking).
+.ie n .IP """EV_EMBED""" 4
+.el .IP "\f(CWEV_EMBED\fR" 4
+.IX Item "EV_EMBED"
+The embedded event loop specified in the \f(CW\*(C`ev_embed\*(C'\fR watcher needs attention.
+.ie n .IP """EV_FORK""" 4
+.el .IP "\f(CWEV_FORK\fR" 4
+.IX Item "EV_FORK"
+The event loop has been resumed in the child process after fork (see
+\&\f(CW\*(C`ev_fork\*(C'\fR).
 .ie n .IP """EV_ERROR""" 4
 .el .IP "\f(CWEV_ERROR\fR" 4
 .IX Item "EV_ERROR"
@@ -894,9 +967,9 @@ The file descriptor being watched.
 .IX Item "int events [read-only]"
 The events being watched.
 .PP
-Example: call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well
+Example: Call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well
 readable, but only once. Since it is likely line\-buffered, you could
-attempt to read a whole line in the callback:
+attempt to read a whole line in the callback.
 .PP
 .Vb 6
 \&  static void
@@ -998,7 +1071,7 @@ The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher t
 or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any),
 which is also when any modifications are taken into account.
 .PP
-Example: create a timer that fires after 60 seconds.
+Example: Create a timer that fires after 60 seconds.
 .PP
 .Vb 5
 \&  static void
@@ -1014,7 +1087,7 @@ Example: create a timer that fires after 60 seconds.
 \&  ev_timer_start (loop, &mytimer);
 .Ve
 .PP
-Example: create a timeout timer that times out after 10 seconds of
+Example: Create a timeout timer that times out after 10 seconds of
 inactivity.
 .PP
 .Vb 5
@@ -1149,7 +1222,7 @@ The current reschedule callback, or \f(CW0\fR, if this functionality is
 switched off. Can be changed any time, but changes only take effect when
 the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called.
 .PP
-Example: call a callback every hour, or, more precisely, whenever the
+Example: Call a callback every hour, or, more precisely, whenever the
 system clock is divisible by 3600. The callback invocation times have
 potentially a lot of jittering, but good long-term stability.
 .PP
@@ -1167,7 +1240,7 @@ potentially a lot of jittering, but good long-term stability.
 \&  ev_periodic_start (loop, &hourly_tick);
 .Ve
 .PP
-Example: the same as above, but use a reschedule callback to do it:
+Example: The same as above, but use a reschedule callback to do it:
 .PP
 .Vb 1
 \&  #include <math.h>
@@ -1185,7 +1258,7 @@ Example: the same as above, but use a reschedule callback to do it:
 \&  ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);
 .Ve
 .PP
-Example: call a callback every hour, starting now:
+Example: Call a callback every hour, starting now:
 .PP
 .Vb 4
 \&  struct ev_periodic hourly_tick;
@@ -1246,7 +1319,7 @@ The process id that detected a status change.
 The process exit/trace status caused by \f(CW\*(C`rpid\*(C'\fR (see your systems
 \&\f(CW\*(C`waitpid\*(C'\fR and \f(CW\*(C`sys/wait.h\*(C'\fR documentation for details).
 .PP
-Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0.
+Example: Try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0.
 .PP
 .Vb 5
 \&  static void
@@ -1380,8 +1453,8 @@ Initialises and configures the idle watcher \- it has no parameters of any
 kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless,
 believe me.
 .PP
-Example: dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR, start it, and in the
-callback, free it. Alos, use no error checking, as usual.
+Example: Dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR watcher, start it, and in the
+callback, free it. Also, use no error checking, as usual.
 .PP
 .Vb 7
 \&  static void
@@ -1615,6 +1688,21 @@ apropriate way for embedded loops.
 .IP "struct ev_loop *loop [read\-only]" 4
 .IX Item "struct ev_loop *loop [read-only]"
 The embedded event loop.
+.ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork"
+.el .Sh "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork"
+.IX Subsection "ev_fork - the audacity to resume the event loop after a fork"
+Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because
+whoever is a good citizen cared to tell libev about it by calling
+\&\f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the
+event loop blocks next and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called,
+and only in the child after the fork. If whoever good citizen calling
+\&\f(CW\*(C`ev_default_fork\*(C'\fR cheats and calls it in the wrong process, the fork
+handlers will be invoked, too, of course.
+.IP "ev_fork_init (ev_signal *, callback)" 4
+.IX Item "ev_fork_init (ev_signal *, callback)"
+Initialises and configures the fork watcher \- it has no parameters of any
+kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless,
+believe me.
 .SH "OTHER FUNCTIONS"
 .IX Header "OTHER FUNCTIONS"
 There are some other functions of possible interest. Described. Here. Now.
@@ -1763,6 +1851,10 @@ For \f(CW\*(C`ev::timer\*(C'\fR and \f(CW\*(C`ev::periodic\*(C'\fR, this invokes
 .el .IP "w\->sweep ()       \f(CWev::embed\fR only" 4
 .IX Item "w->sweep ()       ev::embed only"
 Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR.
+.ie n .IP "w\->update ()      ""ev::stat"" only" 4
+.el .IP "w\->update ()      \f(CWev::stat\fR only" 4
+.IX Item "w->update ()      ev::stat only"
+Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR.
 .RE
 .RS 4
 .RE
@@ -1790,6 +1882,71 @@ the constructor.
 \&    io.start (fd, ev::READ);
 \&  }
 .Ve
+.SH "MACRO MAGIC"
+.IX Header "MACRO MAGIC"
+Libev can be compiled with a variety of options, the most fundemantal is
+\&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines wether (most) functions and
+callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument.
+.PP
+To make it easier to write programs that cope with either variant, the
+following macros are defined:
+.ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4
+.el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4
+.IX Item "EV_A, EV_A_"
+This provides the loop \fIargument\fR for functions, if one is required (\*(L"ev
+loop argument\*(R"). The \f(CW\*(C`EV_A\*(C'\fR form is used when this is the sole argument,
+\&\f(CW\*(C`EV_A_\*(C'\fR is used when other arguments are following. Example:
+.Sp
+.Vb 3
+\&  ev_unref (EV_A);
+\&  ev_timer_add (EV_A_ watcher);
+\&  ev_loop (EV_A_ 0);
+.Ve
+.Sp
+It assumes the variable \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR is in scope,
+which is often provided by the following macro.
+.ie n .IP """EV_P""\fR, \f(CW""EV_P_""" 4
+.el .IP "\f(CWEV_P\fR, \f(CWEV_P_\fR" 4
+.IX Item "EV_P, EV_P_"
+This provides the loop \fIparameter\fR for functions, if one is required (\*(L"ev
+loop parameter\*(R"). The \f(CW\*(C`EV_P\*(C'\fR form is used when this is the sole parameter,
+\&\f(CW\*(C`EV_P_\*(C'\fR is used when other parameters are following. Example:
+.Sp
+.Vb 2
+\&  // this is how ev_unref is being declared
+\&  static void ev_unref (EV_P);
+.Ve
+.Sp
+.Vb 2
+\&  // this is how you can declare your typical callback
+\&  static void cb (EV_P_ ev_timer *w, int revents)
+.Ve
+.Sp
+It declares a parameter \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR, quite
+suitable for use with \f(CW\*(C`EV_A\*(C'\fR.
+.ie n .IP """EV_DEFAULT""\fR, \f(CW""EV_DEFAULT_""" 4
+.el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4
+.IX Item "EV_DEFAULT, EV_DEFAULT_"
+Similar to the other two macros, this gives you the value of the default
+loop, if multiple loops are supported (\*(L"ev loop default\*(R").
+.PP
+Example: Declare and initialise a check watcher, working regardless of
+wether multiple loops are supported or not.
+.PP
+.Vb 5
+\&  static void
+\&  check_cb (EV_P_ ev_timer *w, int revents)
+\&  {
+\&    ev_check_stop (EV_A_ w);
+\&  }
+.Ve
+.PP
+.Vb 4
+\&  ev_check check;
+\&  ev_check_init (&check, check_cb);
+\&  ev_check_start (EV_DEFAULT_ &check);
+\&  ev_loop (EV_DEFAULT_ 0);
+.Ve
 .SH "EMBEDDING"
 .IX Header "EMBEDDING"
 Libev can (and often is) directly embedded into host
@@ -2018,11 +2175,21 @@ defined to be \f(CW0\fR, then they are not.
 .IX Item "EV_STAT_ENABLE"
 If undefined or defined to be \f(CW1\fR, then stat watchers are supported. If
 defined to be \f(CW0\fR, then they are not.
+.IP "\s-1EV_FORK_ENABLE\s0" 4
+.IX Item "EV_FORK_ENABLE"
+If undefined or defined to be \f(CW1\fR, then fork watchers are supported. If
+defined to be \f(CW0\fR, then they are not.
 .IP "\s-1EV_MINIMAL\s0" 4
 .IX Item "EV_MINIMAL"
 If you need to shave off some kilobytes of code at the expense of some
 speed, define this symbol to \f(CW1\fR. Currently only used for gcc to override
 some inlining decisions, saves roughly 30% codesize of amd64.
+.IP "\s-1EV_PID_HASHSIZE\s0" 4
+.IX Item "EV_PID_HASHSIZE"
+\&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by
+pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more
+than enough. If you need to manage thousands of children you might want to
+increase this value.
 .IP "\s-1EV_COMMON\s0" 4
 .IX Item "EV_COMMON"
 By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining