[ViewVC] Diff of: cvs/libev/ev.pod

Comparing libev/ev.pod (file contents):
Revision 1.50 by root, Tue Nov 27 10:59:11 2007 UTC vs.
Revision 1.54 by root, Tue Nov 27 20:26:51 2007 UTC

 libev - a high performance full-featured event loop written in C
 =head1 SYNOPSIS
   #include <ev.h>
+=head1 EXAMPLE PROGRAM
+  #include <ev.h>
+  ev_io stdin_watcher;
+  ev_timer timeout_watcher;
+  /* 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 */
+  }
+  static void
+  timeout_cb (EV_P_ struct ev_timer *w, int revents)
+  {
+    /* puts ("timeout"); */
+    ev_unloop (EV_A_ EVUNLOOP_ONE); /* leave one loop call */
+  }
+  int
+  main (void)
+  {
+    struct ev_loop *loop = ev_default_loop (0);
+    /* 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);
+    /* simple non-repeating 5.5 second timeout */
+    ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);
+    ev_timer_start (loop, &timeout_watcher);
+    /* loop till timeout or data ready */
+    ev_loop (loop, 0);
+    return 0;
+  }
 =head1 DESCRIPTION
 Libev is an event loop: you register interest in certain events (such as a
 file descriptor being readable or a timeout occuring), and it will manage
 details of the event, and then hand it over to libev by I<starting> the
 watcher.
 =head1 FEATURES
-Libev supports select, poll, the linux-specific epoll and the bsd-specific
+Libev supports C<select>, C<poll>, the linux-specific C<epoll>, the
-kqueue mechanisms for file descriptor events, relative timers, absolute
+bsd-specific C<kqueue> and the solaris-specific event port mechanisms
-timers with customised rescheduling, signal events, process status change
+for file descriptor events (C<ev_io>), relative timers (C<ev_timer>),
-events (related to SIGCHLD), and event watchers dealing with the event
+absolute timers with customised rescheduling (C<ev_periodic>), synchronous
-loop mechanism itself (idle, prepare and check watchers). It also is quite
+signals (C<ev_signal>), process status change events (C<ev_child>), and
+event watchers dealing with the event loop mechanism itself (C<ev_idle>,
+C<ev_embed>, C<ev_prepare> and C<ev_check> watchers) as well as
+file watchers (C<ev_stat>) and even limited support for fork events
+(C<ev_fork>).
+It also is quite fast (see this
-fast (see this L<benchmark|http://libev.schmorp.de/bench.html> comparing
+L<benchmark|http://libev.schmorp.de/bench.html> comparing it to libevent
-it to libevent for example).
+for example).
 =head1 CONVENTIONS
-Libev is very configurable. In this manual the default configuration
+Libev is very configurable. In this manual the default configuration will
-will be described, which supports multiple event loops. For more info
+be described, which supports multiple event loops. For more info about
-about various configuration options please have a look at the file
+various configuration options please have a look at B<EMBED> section in
-F<README.embed> in the libev distribution. If libev was configured without
+this manual. If libev was configured without support for multiple event
-support for multiple event loops, then all functions taking an initial
+loops, then all functions taking an initial argument of name C<loop>
-argument of name C<loop> (which is always of type C<struct ev_loop *>)
+(which is always of type C<struct ev_loop *>) will not have this argument.
-will not have this argument.
 =head1 TIME REPRESENTATION
 Libev represents time as a single floating point number, representing the
 (fractional) number of seconds since the (POSIX) epoch (somewhere near
 Usually, it's a good idea to terminate if the major versions mismatch,
 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.
-Example: make sure we haven't accidentally been linked against the wrong
+Example: Make sure we haven't accidentally been linked against the wrong
-version:
+version.
   assert (("libev version mismatch",
            ev_version_major () == EV_VERSION_MAJOR
            && ev_version_minor () >= EV_VERSION_MINOR));
 C<ev_embeddable_backends () & ev_supported_backends ()>, likewise for
 recommended ones.
 See the description of C<ev_embed> watchers for more info.
-=item ev_set_allocator (void *(*cb)(void *ptr, long size))
+=item ev_set_allocator (void *(*cb)(void *ptr, size_t size))
-Sets the allocation function to use (the prototype is similar to the
+Sets the allocation function to use (the prototype and semantics are
-realloc C function, the semantics are identical). It is used to allocate
+identical to the realloc C function). It is used to allocate and free
-and free memory (no surprises here). If it returns zero when memory
+memory (no surprises here). If it returns zero when memory needs to be
-needs to be allocated, the library might abort or take some potentially
+allocated, the library might abort or take some potentially destructive
-destructive action. The default is your system realloc function.
+action. The default is your system realloc function.
 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.
-Example: replace the libev allocator with one that waits a bit and then
+Example: Replace the libev allocator with one that waits a bit and then
-retries: better than mine).
+retries).
    static void *
-   persistent_realloc (void *ptr, long size)
+   persistent_realloc (void *ptr, size_t size)
    {
      for (;;)
        {
          void *newptr = realloc (ptr, size);
 callback is set, then libev will expect it to remedy the sitution, no
 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).
-Example: do the same thing as libev does internally:
+Example: This is basically the same thing that libev does internally, too.
    static void
    fatal_error (const char *msg)
    {
      perror (msg);
 Similar to C<ev_default_loop>, but always creates a new event loop that is
 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).
-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.
   struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);
   if (!epoller)
     fatal ("no epoll found here, maybe it hides under your chair");
      Signals and child watchers are implemented as I/O watchers, and will
      be handled here by queueing them when their watcher gets executed.
    - If ev_unloop has been called or EVLOOP_ONESHOT or EVLOOP_NONBLOCK
      were used, return, otherwise continue with step *.
-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.
    ... queue jobs here, make sure they register event watchers as long
    ... as they still have work to do (even an idle watcher will do..)
    ev_loop (my_loop, 0);
 visible to the libev user and should not keep C<ev_loop> from exiting if
 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 I<unref after start> and I<ref before stop>.
-Example: create a signal watcher, but keep it from keeping C<ev_loop>
+Example: Create a signal watcher, but keep it from keeping C<ev_loop>
 running when nothing else is active.
-  struct dv_signal exitsig;
+  struct ev_signal exitsig;
   ev_signal_init (&exitsig, sig_cb, SIGINT);
-  ev_signal_start (myloop, &exitsig);
+  ev_signal_start (loop, &exitsig);
-  evf_unref (myloop);
+  evf_unref (loop);
-Example: for some weird reason, unregister the above signal handler again.
+Example: For some weird reason, unregister the above signal handler again.
-  ev_ref (myloop);
+  ev_ref (loop);
-  ev_signal_stop (myloop, &exitsig);
+  ev_signal_stop (loop, &exitsig);
 =back
 =head1 ANATOMY OF A WATCHER
 The events being watched.
 =back
-Example: call C<stdin_readable_cb> when STDIN_FILENO has become, well
+Example: Call C<stdin_readable_cb> when STDIN_FILENO 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.
   static void
   stdin_readable_cb (struct ev_loop *loop, struct ev_io *w, int revents)
   {
      ev_io_stop (loop, w);
 or C<ev_timer_again> is called and determines the next timeout (if any),
 which is also when any modifications are taken into account.
 =back
-Example: create a timer that fires after 60 seconds.
+Example: Create a timer that fires after 60 seconds.
   static void
   one_minute_cb (struct ev_loop *loop, struct ev_timer *w, int revents)
   {
     .. one minute over, w is actually stopped right here
   struct ev_timer mytimer;
   ev_timer_init (&mytimer, one_minute_cb, 60., 0.);
   ev_timer_start (loop, &mytimer);
-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.
   static void
   timeout_cb (struct ev_loop *loop, struct ev_timer *w, int revents)
   {
 switched off. Can be changed any time, but changes only take effect when
 the periodic timer fires or C<ev_periodic_again> is being called.
 =back
-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.
   static void
   clock_cb (struct ev_loop *loop, struct ev_io *w, int revents)
   struct ev_periodic hourly_tick;
   ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);
   ev_periodic_start (loop, &hourly_tick);
-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:
   #include <math.h>
   static ev_tstamp
   my_scheduler_cb (struct ev_periodic *w, ev_tstamp now)
     return fmod (now, 3600.) + 3600.;
   }
   ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);
-Example: call a callback every hour, starting now:
+Example: Call a callback every hour, starting now:
   struct ev_periodic hourly_tick;
   ev_periodic_init (&hourly_tick, clock_cb,
                     fmod (ev_now (loop), 3600.), 3600., 0);
   ev_periodic_start (loop, &hourly_tick);
 The process exit/trace status caused by C<rpid> (see your systems
 C<waitpid> and C<sys/wait.h> documentation for details).
 =back
-Example: try to exit cleanly on SIGINT and SIGTERM.
+Example: Try to exit cleanly on SIGINT and SIGTERM.
   static void
   sigint_cb (struct ev_loop *loop, struct ev_signal *w, int revents)
   {
     ev_unloop (loop, EVUNLOOP_ALL);
 kind. There is a C<ev_idle_set> macro, but using it is utterly pointless,
 believe me.
 =back
-Example: dynamically allocate an C<ev_idle>, start it, and in the
+Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the
-callback, free it. Alos, use no error checking, as usual.
+callback, free it. Also, use no error checking, as usual.
   static void
   idle_cb (struct ev_loop *loop, struct ev_idle *w, int revents)
   {
     free (w);
 If you need to shave off some kilobytes of code at the expense of some
 speed, define this symbol to C<1>. Currently only used for gcc to override
 some inlining decisions, saves roughly 30% codesize of amd64.
+=item EV_PID_HASHSIZE
+C<ev_child> watchers use a small hash table to distribute workload by
+pid. The default size is C<16> (or C<1> with C<EV_MINIMAL>), usually more
+than enough. If you need to manage thousands of children you might want to
+increase this value.
 =item EV_COMMON
 By default, all watchers have a C<void *data> member. By redefining
 this macro to a something else you can include more and other types of
 members. You have to define it each time you include one of the files,

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Comparing libev/ev.pod (file contents): Revision 1.50 by root, Tue Nov 27 10:59:11 2007 UTC vs. Revision 1.54 by root, Tue Nov 27 20:26:51 2007 UTC

Diff Legend

Comparing libev/ev.pod (file contents):
Revision 1.50 by root, Tue Nov 27 10:59:11 2007 UTC vs.
Revision 1.54 by root, Tue Nov 27 20:26:51 2007 UTC