X-Git-Url: https://git.llucax.com/software/libev.git/blobdiff_plain/759051fdbf8b3370705e05dac2e2d7525d882e4c..b3c85cba31a5669ce3e1995d8660542354957a53:/ev.3 diff --git a/ev.3 b/ev.3 index 1fdfe55..a7805ec 100644 --- a/ev.3 +++ b/ev.3 @@ -128,8 +128,8 @@ .rm #[ #] #H #V #F C .\" ======================================================================== .\" -.IX Title """ 1" -.TH "" 1 "2007-12-09" "perl v5.8.8" "User Contributed Perl Documentation" +.IX Title "EV 1" +.TH EV 1 "2007-12-19" "perl v5.8.8" "User Contributed Perl Documentation" .SH "NAME" libev \- a high performance full\-featured event loop written in C .SH "SYNOPSIS" @@ -245,7 +245,9 @@ Libev represents time as a single floating point number, representing the the beginning of 1970, details are complicated, don't ask). This type is called \f(CW\*(C`ev_tstamp\*(C'\fR, which is what you should use too. It usually aliases to the \f(CW\*(C`double\*(C'\fR type in C, and when you need to do any calculations on -it, you should treat it as such. +it, you should treat it as some floatingpoint value. Unlike the name +component \f(CW\*(C`stamp\*(C'\fR might indicate, it is also used for time differences +throughout libev. .SH "GLOBAL FUNCTIONS" .IX Header "GLOBAL FUNCTIONS" These functions can be called anytime, even before initialising the @@ -261,14 +263,14 @@ you actually want to know. .IP "int ev_version_minor ()" 4 .IX Item "int ev_version_minor ()" .PD -You can find out the major and minor \s-1API/ABI\s0 version numbers of the library +You can find out the major and minor \s-1ABI\s0 version numbers of the library you linked against by calling the functions \f(CW\*(C`ev_version_major\*(C'\fR and \&\f(CW\*(C`ev_version_minor\*(C'\fR. If you want, you can compare against the global symbols \f(CW\*(C`EV_VERSION_MAJOR\*(C'\fR and \f(CW\*(C`EV_VERSION_MINOR\*(C'\fR, which specify the version of the library your program was compiled against. .Sp -These version numbers refer to the \s-1API\s0 and \s-1ABI\s0 version of the library, not -the release version. +These version numbers refer to the \s-1ABI\s0 version of the library, not the +release version. .Sp Usually, it's a good idea to terminate if the major versions mismatch, as this indicates an incompatible change. Minor versions are usually @@ -557,8 +559,17 @@ etc.). None of the active event watchers will be stopped in the normal sense, so e.g. \f(CW\*(C`ev_is_active\*(C'\fR might still return true. It is your responsibility to either stop all watchers cleanly yoursef \fIbefore\fR calling this function, or cope with the fact afterwards (which is usually -the easiest thing, youc na just ignore the watchers and/or \f(CW\*(C`free ()\*(C'\fR them +the easiest thing, you can just ignore the watchers and/or \f(CW\*(C`free ()\*(C'\fR them for example). +.Sp +Not that certain global state, such as signal state, will not be freed by +this function, and related watchers (such as signal and child watchers) +would need to be stopped manually. +.Sp +In general it is not advisable to call this function except in the +rare occasion where you really need to free e.g. the signal handling +pipe fds. If you need dynamically allocated loops it is better to use +\&\f(CW\*(C`ev_loop_new\*(C'\fR and \f(CW\*(C`ev_loop_destroy\*(C'\fR). .IP "ev_loop_destroy (loop)" 4 .IX Item "ev_loop_destroy (loop)" Like \f(CW\*(C`ev_default_destroy\*(C'\fR, but destroys an event loop created by an @@ -1067,6 +1078,31 @@ play around with an Xlib connection), then you have to seperately re-test whether a file descriptor is really ready with a known-to-be good interface such as poll (fortunately in our Xlib example, Xlib already does this on its own, so its quite safe to use). +.PP +\fIThe special problem of disappearing file descriptors\fR +.IX Subsection "The special problem of disappearing file descriptors" +.PP +Some backends (e.g kqueue, epoll) need to be told about closing a file +descriptor (either by calling \f(CW\*(C`close\*(C'\fR explicitly or by any other means, +such as \f(CW\*(C`dup\*(C'\fR). The reason is that you register interest in some file +descriptor, but when it goes away, the operating system will silently drop +this interest. If another file descriptor with the same number then is +registered with libev, there is no efficient way to see that this is, in +fact, a different file descriptor. +.PP +To avoid having to explicitly tell libev about such cases, libev follows +the following policy: Each time \f(CW\*(C`ev_io_set\*(C'\fR is being called, libev +will assume that this is potentially a new file descriptor, otherwise +it is assumed that the file descriptor stays the same. That means that +you \fIhave\fR to call \f(CW\*(C`ev_io_set\*(C'\fR (or \f(CW\*(C`ev_io_init\*(C'\fR) when you change the +descriptor even if the file descriptor number itself did not change. +.PP +This is how one would do it normally anyway, the important point is that +the libev application should not optimise around libev but should leave +optimisations to libev. +.PP +\fIWatcher-Specific Functions\fR +.IX Subsection "Watcher-Specific Functions" .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" .PD 0 @@ -1129,6 +1165,9 @@ on the current time, use something like this to adjust for this: The callback is guarenteed to be invoked only when its timeout has passed, but if multiple timers become ready during the same loop iteration then order of execution is undefined. +.PP +\fIWatcher-Specific Functions and Data Members\fR +.IX Subsection "Watcher-Specific Functions and Data Members" .IP "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" 4 .IX Item "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" .PD 0 @@ -1249,6 +1288,9 @@ rules. As with timers, the callback is guarenteed to be invoked only when the time (\f(CW\*(C`at\*(C'\fR) has been passed, but if multiple periodic timers become ready during the same loop iteration then order of execution is undefined. +.PP +\fIWatcher-Specific Functions and Data Members\fR +.IX Subsection "Watcher-Specific Functions and Data Members" .IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" 4 .IX Item "ev_periodic_init (ev_periodic *, callback, ev_tstamp at, ev_tstamp interval, reschedule_cb)" .PD 0 @@ -1350,6 +1392,10 @@ called. 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. +.IP "ev_tstamp at [read\-only]" 4 +.IX Item "ev_tstamp at [read-only]" +When active, contains the absolute time that the watcher is supposed to +trigger next. .PP Example: Call a callback every hour, or, more precisely, whenever the system clock is divisible by 3600. The callback invocation times have @@ -1409,6 +1455,9 @@ with the kernel (thus it coexists with your own signal handlers as long as you don't register any with libev). Similarly, when the last signal watcher for a signal is stopped libev will reset the signal handler to \&\s-1SIG_DFL\s0 (regardless of what it was set to before). +.PP +\fIWatcher-Specific Functions and Data Members\fR +.IX Subsection "Watcher-Specific Functions and Data Members" .IP "ev_signal_init (ev_signal *, callback, int signum)" 4 .IX Item "ev_signal_init (ev_signal *, callback, int signum)" .PD 0 @@ -1425,6 +1474,9 @@ The signal the watcher watches out for. .IX Subsection "ev_child - watch out for process status changes" Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to some child status changes (most typically when a child of yours dies). +.PP +\fIWatcher-Specific Functions and Data Members\fR +.IX Subsection "Watcher-Specific Functions and Data Members" .IP "ev_child_init (ev_child *, callback, int pid)" 4 .IX Item "ev_child_init (ev_child *, callback, int pid)" .PD 0 @@ -1499,6 +1551,9 @@ semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers, which means that libev sometime to fall back to regular polling again even with inotify, but changes are usually detected immediately, and if the file exists there will be no polling. +.PP +\fIWatcher-Specific Functions and Data Members\fR +.IX Subsection "Watcher-Specific Functions and Data Members" .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" .PD 0 @@ -1587,6 +1642,9 @@ Apart from keeping your process non-blocking (which is a useful effect on its own sometimes), idle watchers are a good place to do \&\*(L"pseudo\-background processing\*(R", or delay processing stuff to after the event loop has handled all outstanding events. +.PP +\fIWatcher-Specific Functions and Data Members\fR +.IX Subsection "Watcher-Specific Functions and Data Members" .IP "ev_idle_init (ev_signal *, callback)" 4 .IX Item "ev_idle_init (ev_signal *, callback)" Initialises and configures the idle watcher \- it has no parameters of any @@ -1661,6 +1719,9 @@ their job. As \f(CW\*(C`ev_check\*(C'\fR watchers are often used to embed other loops those other event loops might be in an unusable state until their \&\f(CW\*(C`ev_check\*(C'\fR watcher ran (always remind yourself to coexist peacefully with others). +.PP +\fIWatcher-Specific Functions and Data Members\fR +.IX Subsection "Watcher-Specific Functions and Data Members" .IP "ev_prepare_init (ev_prepare *, callback)" 4 .IX Item "ev_prepare_init (ev_prepare *, callback)" .PD 0 @@ -1917,6 +1978,9 @@ create it, and if that fails, use the normal loop for everything: \& else \& loop_lo = loop_hi; .Ve +.PP +\fIWatcher-Specific Functions and Data Members\fR +.IX Subsection "Watcher-Specific Functions and Data Members" .IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4 .IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" .PD 0 @@ -1946,6 +2010,9 @@ event loop blocks next and before \f(CW\*(C`ev_check\*(C'\fR watchers are being 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. +.PP +\fIWatcher-Specific Functions and Data Members\fR +.IX Subsection "Watcher-Specific Functions and Data Members" .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 @@ -2149,18 +2216,18 @@ constructor already stores the event loop. .IP "w\->stop ()" 4 .IX Item "w->stop ()" Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. -.ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 -.el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 -.IX Item "w->again () ev::timer, ev::periodic only" +.ie n .IP "w\->again () (""ev::timer""\fR, \f(CW""ev::periodic"" only)" 4 +.el .IP "w\->again () (\f(CWev::timer\fR, \f(CWev::periodic\fR only)" 4 +.IX Item "w->again () (ev::timer, ev::periodic only)" For \f(CW\*(C`ev::timer\*(C'\fR and \f(CW\*(C`ev::periodic\*(C'\fR, this invokes the corresponding \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. -.ie n .IP "w\->sweep () ""ev::embed"" only" 4 -.el .IP "w\->sweep () \f(CWev::embed\fR only" 4 -.IX Item "w->sweep () ev::embed only" +.ie n .IP "w\->sweep () (""ev::embed"" only)" 4 +.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" +.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 @@ -2194,9 +2261,9 @@ the constructor. .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 whether (most) functions and -callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. +Libev can be compiled with a variety of options, the most fundamantal +of which is \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (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: @@ -2564,6 +2631,36 @@ definition and a statement, respectively. See the \fIev.v\fR header file for their default definitions. One possible use for overriding these is to avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use method calls instead of plain function calls in \*(C+. +.Sh "\s-1EXPORTED\s0 \s-1API\s0 \s-1SYMBOLS\s0" +.IX Subsection "EXPORTED API SYMBOLS" +If you need to re-export the \s-1API\s0 (e.g. via a dll) and you need a list of +exported symbols, you can use the provided \fISymbol.*\fR files which list +all public symbols, one per line: +.Sp +.Vb 2 +\& Symbols.ev for libev proper +\& Symbols.event for the libevent emulation +.Ve +.Sp +This can also be used to rename all public symbols to avoid clashes with +multiple versions of libev linked together (which is obviously bad in +itself, but sometimes it is inconvinient to avoid this). +.Sp +A sed comamnd like this will create wrapper \f(CW\*(C`#define\*(C'\fR's that you need to +include before including \fIev.h\fR: +.Sp +.Vb 1 +\& wrap.h +.Ve +.Sp +This would create a file \fIwrap.h\fR which essentially looks like this: +.Sp +.Vb 4 +\& #define ev_backend myprefix_ev_backend +\& #define ev_check_start myprefix_ev_check_start +\& #define ev_check_stop myprefix_ev_check_stop +\& ... +.Ve .Sh "\s-1EXAMPLES\s0" .IX Subsection "EXAMPLES" For a real-world example of a program the includes libev