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134 | .IX Title "LIBEV 3" |
126 | .IX Title "LIBEV 3" |
135 | .TH LIBEV 3 "2009-04-25" "libev-3.6" "libev - high performance full featured event loop" |
127 | .TH LIBEV 3 "2009-07-15" "libev-3.7" "libev - high performance full featured event loop" |
136 | .\" For nroff, turn off justification. Always turn off hyphenation; it makes |
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138 | .if n .ad l |
130 | .if n .ad l |
139 | .nh |
131 | .nh |
140 | .SH "NAME" |
132 | .SH "NAME" |
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142 | .SH "SYNOPSIS" |
134 | .SH "SYNOPSIS" |
143 | .IX Header "SYNOPSIS" |
135 | .IX Header "SYNOPSIS" |
144 | .Vb 1 |
136 | .Vb 1 |
145 | \& #include <ev.h> |
137 | \& #include <ev.h> |
146 | .Ve |
138 | .Ve |
147 | .Sh "\s-1EXAMPLE\s0 \s-1PROGRAM\s0" |
139 | .SS "\s-1EXAMPLE\s0 \s-1PROGRAM\s0" |
148 | .IX Subsection "EXAMPLE PROGRAM" |
140 | .IX Subsection "EXAMPLE PROGRAM" |
149 | .Vb 2 |
141 | .Vb 2 |
150 | \& // a single header file is required |
142 | \& // a single header file is required |
151 | \& #include <ev.h> |
143 | \& #include <ev.h> |
152 | \& |
144 | \& |
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230 | .PP |
222 | .PP |
231 | You register interest in certain events by registering so-called \fIevent |
223 | You register interest in certain events by registering so-called \fIevent |
232 | watchers\fR, which are relatively small C structures you initialise with the |
224 | watchers\fR, which are relatively small C structures you initialise with the |
233 | details of the event, and then hand it over to libev by \fIstarting\fR the |
225 | details of the event, and then hand it over to libev by \fIstarting\fR the |
234 | watcher. |
226 | watcher. |
235 | .Sh "\s-1FEATURES\s0" |
227 | .SS "\s-1FEATURES\s0" |
236 | .IX Subsection "FEATURES" |
228 | .IX Subsection "FEATURES" |
237 | Libev supports \f(CW\*(C`select\*(C'\fR, \f(CW\*(C`poll\*(C'\fR, the Linux-specific \f(CW\*(C`epoll\*(C'\fR, the |
229 | Libev supports \f(CW\*(C`select\*(C'\fR, \f(CW\*(C`poll\*(C'\fR, the Linux-specific \f(CW\*(C`epoll\*(C'\fR, the |
238 | BSD-specific \f(CW\*(C`kqueue\*(C'\fR and the Solaris-specific event port mechanisms |
230 | BSD-specific \f(CW\*(C`kqueue\*(C'\fR and the Solaris-specific event port mechanisms |
239 | for file descriptor events (\f(CW\*(C`ev_io\*(C'\fR), the Linux \f(CW\*(C`inotify\*(C'\fR interface |
231 | for file descriptor events (\f(CW\*(C`ev_io\*(C'\fR), the Linux \f(CW\*(C`inotify\*(C'\fR interface |
240 | (for \f(CW\*(C`ev_stat\*(C'\fR), relative timers (\f(CW\*(C`ev_timer\*(C'\fR), absolute timers |
232 | (for \f(CW\*(C`ev_stat\*(C'\fR), relative timers (\f(CW\*(C`ev_timer\*(C'\fR), absolute timers |
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244 | \&\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 |
236 | \&\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 |
245 | file watchers (\f(CW\*(C`ev_stat\*(C'\fR) and even limited support for fork events |
237 | file watchers (\f(CW\*(C`ev_stat\*(C'\fR) and even limited support for fork events |
246 | (\f(CW\*(C`ev_fork\*(C'\fR). |
238 | (\f(CW\*(C`ev_fork\*(C'\fR). |
247 | .PP |
239 | .PP |
248 | It also is quite fast (see this |
240 | It also is quite fast (see this |
249 | benchmark comparing it to libevent |
241 | <benchmark> comparing it to libevent |
250 | for example). |
242 | for example). |
251 | .Sh "\s-1CONVENTIONS\s0" |
243 | .SS "\s-1CONVENTIONS\s0" |
252 | .IX Subsection "CONVENTIONS" |
244 | .IX Subsection "CONVENTIONS" |
253 | Libev is very configurable. In this manual the default (and most common) |
245 | Libev is very configurable. In this manual the default (and most common) |
254 | configuration will be described, which supports multiple event loops. For |
246 | configuration will be described, which supports multiple event loops. For |
255 | more info about various configuration options please have a look at |
247 | more info about various configuration options please have a look at |
256 | \&\fB\s-1EMBED\s0\fR section in this manual. If libev was configured without support |
248 | \&\fB\s-1EMBED\s0\fR section in this manual. If libev was configured without support |
257 | for multiple event loops, then all functions taking an initial argument of |
249 | for multiple event loops, then all functions taking an initial argument of |
258 | name \f(CW\*(C`loop\*(C'\fR (which is always of type \f(CW\*(C`ev_loop *\*(C'\fR) will not have |
250 | name \f(CW\*(C`loop\*(C'\fR (which is always of type \f(CW\*(C`ev_loop *\*(C'\fR) will not have |
259 | this argument. |
251 | this argument. |
260 | .Sh "\s-1TIME\s0 \s-1REPRESENTATION\s0" |
252 | .SS "\s-1TIME\s0 \s-1REPRESENTATION\s0" |
261 | .IX Subsection "TIME REPRESENTATION" |
253 | .IX Subsection "TIME REPRESENTATION" |
262 | Libev represents time as a single floating point number, representing |
254 | Libev represents time as a single floating point number, representing |
263 | the (fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere |
255 | the (fractional) number of seconds since the (\s-1POSIX\s0) epoch (somewhere |
264 | near the beginning of 1970, details are complicated, don't ask). This |
256 | near the beginning of 1970, details are complicated, don't ask). This |
265 | type is called \f(CW\*(C`ev_tstamp\*(C'\fR, which is what you should use too. It usually |
257 | type is called \f(CW\*(C`ev_tstamp\*(C'\fR, which is what you should use too. It usually |
… | |
… | |
749 | happily wraps around with enough iterations. |
741 | happily wraps around with enough iterations. |
750 | .Sp |
742 | .Sp |
751 | This value can sometimes be useful as a generation counter of sorts (it |
743 | This value can sometimes be useful as a generation counter of sorts (it |
752 | \&\*(L"ticks\*(R" the number of loop iterations), as it roughly corresponds with |
744 | \&\*(L"ticks\*(R" the number of loop iterations), as it roughly corresponds with |
753 | \&\f(CW\*(C`ev_prepare\*(C'\fR and \f(CW\*(C`ev_check\*(C'\fR calls. |
745 | \&\f(CW\*(C`ev_prepare\*(C'\fR and \f(CW\*(C`ev_check\*(C'\fR calls. |
|
|
746 | .IP "unsigned int ev_loop_depth (loop)" 4 |
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|
747 | .IX Item "unsigned int ev_loop_depth (loop)" |
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|
748 | Returns the number of times \f(CW\*(C`ev_loop\*(C'\fR was entered minus the number of |
|
|
749 | times \f(CW\*(C`ev_loop\*(C'\fR was exited, in other words, the recursion depth. |
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|
750 | .Sp |
|
|
751 | Outside \f(CW\*(C`ev_loop\*(C'\fR, this number is zero. In a callback, this number is |
|
|
752 | \&\f(CW1\fR, unless \f(CW\*(C`ev_loop\*(C'\fR was invoked recursively (or from another thread), |
|
|
753 | in which case it is higher. |
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|
754 | .Sp |
|
|
755 | Leaving \f(CW\*(C`ev_loop\*(C'\fR abnormally (setjmp/longjmp, cancelling the thread |
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756 | etc.), doesn't count as exit. |
754 | .IP "unsigned int ev_backend (loop)" 4 |
757 | .IP "unsigned int ev_backend (loop)" 4 |
755 | .IX Item "unsigned int ev_backend (loop)" |
758 | .IX Item "unsigned int ev_backend (loop)" |
756 | Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in |
759 | Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in |
757 | use. |
760 | use. |
758 | .IP "ev_tstamp ev_now (loop)" 4 |
761 | .IP "ev_tstamp ev_now (loop)" 4 |
… | |
… | |
946 | .Sp |
949 | .Sp |
947 | By setting a higher \fIio collect interval\fR you allow libev to spend more |
950 | By setting a higher \fIio collect interval\fR you allow libev to spend more |
948 | time collecting I/O events, so you can handle more events per iteration, |
951 | time collecting I/O events, so you can handle more events per iteration, |
949 | at the cost of increasing latency. Timeouts (both \f(CW\*(C`ev_periodic\*(C'\fR and |
952 | at the cost of increasing latency. Timeouts (both \f(CW\*(C`ev_periodic\*(C'\fR and |
950 | \&\f(CW\*(C`ev_timer\*(C'\fR) will be not affected. Setting this to a non-null value will |
953 | \&\f(CW\*(C`ev_timer\*(C'\fR) will be not affected. Setting this to a non-null value will |
951 | introduce an additional \f(CW\*(C`ev_sleep ()\*(C'\fR call into most loop iterations. |
954 | introduce an additional \f(CW\*(C`ev_sleep ()\*(C'\fR call into most loop iterations. The |
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955 | sleep time ensures that libev will not poll for I/O events more often then |
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956 | once per this interval, on average. |
952 | .Sp |
957 | .Sp |
953 | Likewise, by setting a higher \fItimeout collect interval\fR you allow libev |
958 | Likewise, by setting a higher \fItimeout collect interval\fR you allow libev |
954 | to spend more time collecting timeouts, at the expense of increased |
959 | to spend more time collecting timeouts, at the expense of increased |
955 | latency/jitter/inexactness (the watcher callback will be called |
960 | latency/jitter/inexactness (the watcher callback will be called |
956 | later). \f(CW\*(C`ev_io\*(C'\fR watchers will not be affected. Setting this to a non-null |
961 | later). \f(CW\*(C`ev_io\*(C'\fR watchers will not be affected. Setting this to a non-null |
… | |
… | |
958 | .Sp |
963 | .Sp |
959 | Many (busy) programs can usually benefit by setting the I/O collect |
964 | Many (busy) programs can usually benefit by setting the I/O collect |
960 | interval to a value near \f(CW0.1\fR or so, which is often enough for |
965 | interval to a value near \f(CW0.1\fR or so, which is often enough for |
961 | interactive servers (of course not for games), likewise for timeouts. It |
966 | interactive servers (of course not for games), likewise for timeouts. It |
962 | usually doesn't make much sense to set it to a lower value than \f(CW0.01\fR, |
967 | usually doesn't make much sense to set it to a lower value than \f(CW0.01\fR, |
963 | as this approaches the timing granularity of most systems. |
968 | as this approaches the timing granularity of most systems. Note that if |
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969 | you do transactions with the outside world and you can't increase the |
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970 | parallelity, then this setting will limit your transaction rate (if you |
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971 | need to poll once per transaction and the I/O collect interval is 0.01, |
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972 | then you can't do more than 100 transations per second). |
964 | .Sp |
973 | .Sp |
965 | Setting the \fItimeout collect interval\fR can improve the opportunity for |
974 | Setting the \fItimeout collect interval\fR can improve the opportunity for |
966 | saving power, as the program will \*(L"bundle\*(R" timer callback invocations that |
975 | saving power, as the program will \*(L"bundle\*(R" timer callback invocations that |
967 | are \*(L"near\*(R" in time together, by delaying some, thus reducing the number of |
976 | are \*(L"near\*(R" in time together, by delaying some, thus reducing the number of |
968 | times the process sleeps and wakes up again. Another useful technique to |
977 | times the process sleeps and wakes up again. Another useful technique to |
969 | reduce iterations/wake\-ups is to use \f(CW\*(C`ev_periodic\*(C'\fR watchers and make sure |
978 | reduce iterations/wake\-ups is to use \f(CW\*(C`ev_periodic\*(C'\fR watchers and make sure |
970 | they fire on, say, one-second boundaries only. |
979 | they fire on, say, one-second boundaries only. |
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980 | .Sp |
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981 | Example: we only need 0.1s timeout granularity, and we wish not to poll |
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982 | more often than 100 times per second: |
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983 | .Sp |
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984 | .Vb 2 |
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985 | \& ev_set_timeout_collect_interval (EV_DEFAULT_UC_ 0.1); |
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986 | \& ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01); |
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987 | .Ve |
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988 | .IP "ev_invoke_pending (loop)" 4 |
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989 | .IX Item "ev_invoke_pending (loop)" |
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990 | This call will simply invoke all pending watchers while resetting their |
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991 | pending state. Normally, \f(CW\*(C`ev_loop\*(C'\fR does this automatically when required, |
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992 | but when overriding the invoke callback this call comes handy. |
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993 | .IP "int ev_pending_count (loop)" 4 |
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994 | .IX Item "int ev_pending_count (loop)" |
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995 | Returns the number of pending watchers \- zero indicates that no watchers |
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996 | are pending. |
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997 | .IP "ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(\s-1EV_P\s0))" 4 |
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998 | .IX Item "ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))" |
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999 | This overrides the invoke pending functionality of the loop: Instead of |
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1000 | invoking all pending watchers when there are any, \f(CW\*(C`ev_loop\*(C'\fR will call |
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1001 | this callback instead. This is useful, for example, when you want to |
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1002 | invoke the actual watchers inside another context (another thread etc.). |
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1003 | .Sp |
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1004 | If you want to reset the callback, use \f(CW\*(C`ev_invoke_pending\*(C'\fR as new |
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1005 | callback. |
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1006 | .IP "ev_set_loop_release_cb (loop, void (*release)(\s-1EV_P\s0), void (*acquire)(\s-1EV_P\s0))" 4 |
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1007 | .IX Item "ev_set_loop_release_cb (loop, void (*release)(EV_P), void (*acquire)(EV_P))" |
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1008 | Sometimes you want to share the same loop between multiple threads. This |
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1009 | can be done relatively simply by putting mutex_lock/unlock calls around |
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1010 | each call to a libev function. |
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1011 | .Sp |
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1012 | However, \f(CW\*(C`ev_loop\*(C'\fR can run an indefinite time, so it is not feasible to |
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1013 | wait for it to return. One way around this is to wake up the loop via |
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1014 | \&\f(CW\*(C`ev_unloop\*(C'\fR and \f(CW\*(C`av_async_send\*(C'\fR, another way is to set these \fIrelease\fR |
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1015 | and \fIacquire\fR callbacks on the loop. |
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1016 | .Sp |
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1017 | When set, then \f(CW\*(C`release\*(C'\fR will be called just before the thread is |
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1018 | suspended waiting for new events, and \f(CW\*(C`acquire\*(C'\fR is called just |
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1019 | afterwards. |
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1020 | .Sp |
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1021 | Ideally, \f(CW\*(C`release\*(C'\fR will just call your mutex_unlock function, and |
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1022 | \&\f(CW\*(C`acquire\*(C'\fR will just call the mutex_lock function again. |
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1023 | .Sp |
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1024 | While event loop modifications are allowed between invocations of |
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1025 | \&\f(CW\*(C`release\*(C'\fR and \f(CW\*(C`acquire\*(C'\fR (that's their only purpose after all), no |
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1026 | modifications done will affect the event loop, i.e. adding watchers will |
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1027 | have no effect on the set of file descriptors being watched, or the time |
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1028 | waited. USe an \f(CW\*(C`ev_async\*(C'\fR watcher to wake up \f(CW\*(C`ev_loop\*(C'\fR when you want it |
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1029 | to take note of any changes you made. |
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1030 | .Sp |
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1031 | In theory, threads executing \f(CW\*(C`ev_loop\*(C'\fR will be async-cancel safe between |
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1032 | invocations of \f(CW\*(C`release\*(C'\fR and \f(CW\*(C`acquire\*(C'\fR. |
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1033 | .Sp |
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1034 | See also the locking example in the \f(CW\*(C`THREADS\*(C'\fR section later in this |
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1035 | document. |
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1036 | .IP "ev_set_userdata (loop, void *data)" 4 |
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1037 | .IX Item "ev_set_userdata (loop, void *data)" |
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1038 | .PD 0 |
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1039 | .IP "ev_userdata (loop)" 4 |
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1040 | .IX Item "ev_userdata (loop)" |
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1041 | .PD |
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1042 | Set and retrieve a single \f(CW\*(C`void *\*(C'\fR associated with a loop. When |
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1043 | \&\f(CW\*(C`ev_set_userdata\*(C'\fR has never been called, then \f(CW\*(C`ev_userdata\*(C'\fR returns |
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1044 | \&\f(CW0.\fR |
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1045 | .Sp |
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1046 | These two functions can be used to associate arbitrary data with a loop, |
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1047 | and are intended solely for the \f(CW\*(C`invoke_pending_cb\*(C'\fR, \f(CW\*(C`release\*(C'\fR and |
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1048 | \&\f(CW\*(C`acquire\*(C'\fR callbacks described above, but of course can be (ab\-)used for |
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1049 | any other purpose as well. |
971 | .IP "ev_loop_verify (loop)" 4 |
1050 | .IP "ev_loop_verify (loop)" 4 |
972 | .IX Item "ev_loop_verify (loop)" |
1051 | .IX Item "ev_loop_verify (loop)" |
973 | This function only does something when \f(CW\*(C`EV_VERIFY\*(C'\fR support has been |
1052 | This function only does something when \f(CW\*(C`EV_VERIFY\*(C'\fR support has been |
974 | compiled in, which is the default for non-minimal builds. It tries to go |
1053 | compiled in, which is the default for non-minimal builds. It tries to go |
975 | through all internal structures and checks them for validity. If anything |
1054 | through all internal structures and checks them for validity. If anything |
… | |
… | |
1124 | example it might indicate that a fd is readable or writable, and if your |
1203 | example it might indicate that a fd is readable or writable, and if your |
1125 | callbacks is well-written it can just attempt the operation and cope with |
1204 | callbacks is well-written it can just attempt the operation and cope with |
1126 | the error from \fIread()\fR or \fIwrite()\fR. This will not work in multi-threaded |
1205 | the error from \fIread()\fR or \fIwrite()\fR. This will not work in multi-threaded |
1127 | programs, though, as the fd could already be closed and reused for another |
1206 | programs, though, as the fd could already be closed and reused for another |
1128 | thing, so beware. |
1207 | thing, so beware. |
1129 | .Sh "\s-1GENERIC\s0 \s-1WATCHER\s0 \s-1FUNCTIONS\s0" |
1208 | .SS "\s-1GENERIC\s0 \s-1WATCHER\s0 \s-1FUNCTIONS\s0" |
1130 | .IX Subsection "GENERIC WATCHER FUNCTIONS" |
1209 | .IX Subsection "GENERIC WATCHER FUNCTIONS" |
1131 | .ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4 |
1210 | .ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4 |
1132 | .el .IP "\f(CWev_init\fR (ev_TYPE *watcher, callback)" 4 |
1211 | .el .IP "\f(CWev_init\fR (ev_TYPE *watcher, callback)" 4 |
1133 | .IX Item "ev_init (ev_TYPE *watcher, callback)" |
1212 | .IX Item "ev_init (ev_TYPE *watcher, callback)" |
1134 | This macro initialises the generic portion of a watcher. The contents |
1213 | This macro initialises the generic portion of a watcher. The contents |
… | |
… | |
1258 | returns its \f(CW\*(C`revents\*(C'\fR bitset (as if its callback was invoked). If the |
1337 | returns its \f(CW\*(C`revents\*(C'\fR bitset (as if its callback was invoked). If the |
1259 | watcher isn't pending it does nothing and returns \f(CW0\fR. |
1338 | watcher isn't pending it does nothing and returns \f(CW0\fR. |
1260 | .Sp |
1339 | .Sp |
1261 | Sometimes it can be useful to \*(L"poll\*(R" a watcher instead of waiting for its |
1340 | Sometimes it can be useful to \*(L"poll\*(R" a watcher instead of waiting for its |
1262 | callback to be invoked, which can be accomplished with this function. |
1341 | callback to be invoked, which can be accomplished with this function. |
1263 | .Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
1342 | .SS "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" |
1264 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
1343 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
1265 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
1344 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
1266 | and read at any time: libev will completely ignore it. This can be used |
1345 | and read at any time: libev will completely ignore it. This can be used |
1267 | to associate arbitrary data with your watcher. If you need more data and |
1346 | to associate arbitrary data with your watcher. If you need more data and |
1268 | don't want to allocate memory and store a pointer to it in that data |
1347 | don't want to allocate memory and store a pointer to it in that data |
… | |
… | |
1319 | \& #include <stddef.h> |
1398 | \& #include <stddef.h> |
1320 | \& |
1399 | \& |
1321 | \& static void |
1400 | \& static void |
1322 | \& t1_cb (EV_P_ ev_timer *w, int revents) |
1401 | \& t1_cb (EV_P_ ev_timer *w, int revents) |
1323 | \& { |
1402 | \& { |
1324 | \& struct my_biggy big = (struct my_biggy * |
1403 | \& struct my_biggy big = (struct my_biggy *) |
1325 | \& (((char *)w) \- offsetof (struct my_biggy, t1)); |
1404 | \& (((char *)w) \- offsetof (struct my_biggy, t1)); |
1326 | \& } |
1405 | \& } |
1327 | \& |
1406 | \& |
1328 | \& static void |
1407 | \& static void |
1329 | \& t2_cb (EV_P_ ev_timer *w, int revents) |
1408 | \& t2_cb (EV_P_ ev_timer *w, int revents) |
1330 | \& { |
1409 | \& { |
1331 | \& struct my_biggy big = (struct my_biggy * |
1410 | \& struct my_biggy big = (struct my_biggy *) |
1332 | \& (((char *)w) \- offsetof (struct my_biggy, t2)); |
1411 | \& (((char *)w) \- offsetof (struct my_biggy, t2)); |
1333 | \& } |
1412 | \& } |
1334 | .Ve |
1413 | .Ve |
1335 | .Sh "\s-1WATCHER\s0 \s-1PRIORITY\s0 \s-1MODELS\s0" |
1414 | .SS "\s-1WATCHER\s0 \s-1PRIORITY\s0 \s-1MODELS\s0" |
1336 | .IX Subsection "WATCHER PRIORITY MODELS" |
1415 | .IX Subsection "WATCHER PRIORITY MODELS" |
1337 | Many event loops support \fIwatcher priorities\fR, which are usually small |
1416 | Many event loops support \fIwatcher priorities\fR, which are usually small |
1338 | integers that influence the ordering of event callback invocation |
1417 | integers that influence the ordering of event callback invocation |
1339 | between watchers in some way, all else being equal. |
1418 | between watchers in some way, all else being equal. |
1340 | .PP |
1419 | .PP |
… | |
… | |
1413 | \& // with the default priority are receiving events. |
1492 | \& // with the default priority are receiving events. |
1414 | \& ev_idle_start (EV_A_ &idle); |
1493 | \& ev_idle_start (EV_A_ &idle); |
1415 | \& } |
1494 | \& } |
1416 | \& |
1495 | \& |
1417 | \& static void |
1496 | \& static void |
1418 | \& idle\-cb (EV_P_ ev_idle *w, int revents) |
1497 | \& idle_cb (EV_P_ ev_idle *w, int revents) |
1419 | \& { |
1498 | \& { |
1420 | \& // actual processing |
1499 | \& // actual processing |
1421 | \& read (STDIN_FILENO, ...); |
1500 | \& read (STDIN_FILENO, ...); |
1422 | \& |
1501 | \& |
1423 | \& // have to start the I/O watcher again, as |
1502 | \& // have to start the I/O watcher again, as |
… | |
… | |
1448 | watcher is stopped to your hearts content), or \fI[read\-write]\fR, which |
1527 | watcher is stopped to your hearts content), or \fI[read\-write]\fR, which |
1449 | means you can expect it to have some sensible content while the watcher |
1528 | means you can expect it to have some sensible content while the watcher |
1450 | is active, but you can also modify it. Modifying it may not do something |
1529 | is active, but you can also modify it. Modifying it may not do something |
1451 | sensible or take immediate effect (or do anything at all), but libev will |
1530 | sensible or take immediate effect (or do anything at all), but libev will |
1452 | not crash or malfunction in any way. |
1531 | not crash or malfunction in any way. |
1453 | .ie n .Sh """ev_io"" \- is this file descriptor readable or writable?" |
1532 | .ie n .SS """ev_io"" \- is this file descriptor readable or writable?" |
1454 | .el .Sh "\f(CWev_io\fP \- is this file descriptor readable or writable?" |
1533 | .el .SS "\f(CWev_io\fP \- is this file descriptor readable or writable?" |
1455 | .IX Subsection "ev_io - is this file descriptor readable or writable?" |
1534 | .IX Subsection "ev_io - is this file descriptor readable or writable?" |
1456 | I/O watchers check whether a file descriptor is readable or writable |
1535 | I/O watchers check whether a file descriptor is readable or writable |
1457 | in each iteration of the event loop, or, more precisely, when reading |
1536 | in each iteration of the event loop, or, more precisely, when reading |
1458 | would not block the process and writing would at least be able to write |
1537 | would not block the process and writing would at least be able to write |
1459 | some data. This behaviour is called level-triggering because you keep |
1538 | some data. This behaviour is called level-triggering because you keep |
… | |
… | |
1587 | \& ev_io stdin_readable; |
1666 | \& ev_io stdin_readable; |
1588 | \& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
1667 | \& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
1589 | \& ev_io_start (loop, &stdin_readable); |
1668 | \& ev_io_start (loop, &stdin_readable); |
1590 | \& ev_loop (loop, 0); |
1669 | \& ev_loop (loop, 0); |
1591 | .Ve |
1670 | .Ve |
1592 | .ie n .Sh """ev_timer"" \- relative and optionally repeating timeouts" |
1671 | .ie n .SS """ev_timer"" \- relative and optionally repeating timeouts" |
1593 | .el .Sh "\f(CWev_timer\fP \- relative and optionally repeating timeouts" |
1672 | .el .SS "\f(CWev_timer\fP \- relative and optionally repeating timeouts" |
1594 | .IX Subsection "ev_timer - relative and optionally repeating timeouts" |
1673 | .IX Subsection "ev_timer - relative and optionally repeating timeouts" |
1595 | Timer watchers are simple relative timers that generate an event after a |
1674 | Timer watchers are simple relative timers that generate an event after a |
1596 | given time, and optionally repeating in regular intervals after that. |
1675 | given time, and optionally repeating in regular intervals after that. |
1597 | .PP |
1676 | .PP |
1598 | The timers are based on real time, that is, if you register an event that |
1677 | The timers are based on real time, that is, if you register an event that |
… | |
… | |
1603 | .PP |
1682 | .PP |
1604 | The callback is guaranteed to be invoked only \fIafter\fR its timeout has |
1683 | The callback is guaranteed to be invoked only \fIafter\fR its timeout has |
1605 | passed (not \fIat\fR, so on systems with very low-resolution clocks this |
1684 | passed (not \fIat\fR, so on systems with very low-resolution clocks this |
1606 | might introduce a small delay). If multiple timers become ready during the |
1685 | might introduce a small delay). If multiple timers become ready during the |
1607 | same loop iteration then the ones with earlier time-out values are invoked |
1686 | same loop iteration then the ones with earlier time-out values are invoked |
1608 | before ones with later time-out values (but this is no longer true when a |
1687 | before ones of the same priority with later time-out values (but this is |
1609 | callback calls \f(CW\*(C`ev_loop\*(C'\fR recursively). |
1688 | no longer true when a callback calls \f(CW\*(C`ev_loop\*(C'\fR recursively). |
1610 | .PP |
1689 | .PP |
1611 | \fIBe smart about timeouts\fR |
1690 | \fIBe smart about timeouts\fR |
1612 | .IX Subsection "Be smart about timeouts" |
1691 | .IX Subsection "Be smart about timeouts" |
1613 | .PP |
1692 | .PP |
1614 | Many real-world problems involve some kind of timeout, usually for error |
1693 | Many real-world problems involve some kind of timeout, usually for error |
… | |
… | |
1661 | member and \f(CW\*(C`ev_timer_again\*(C'\fR. |
1740 | member and \f(CW\*(C`ev_timer_again\*(C'\fR. |
1662 | .Sp |
1741 | .Sp |
1663 | At start: |
1742 | At start: |
1664 | .Sp |
1743 | .Sp |
1665 | .Vb 3 |
1744 | .Vb 3 |
1666 | \& ev_timer_init (timer, callback); |
1745 | \& ev_init (timer, callback); |
1667 | \& timer\->repeat = 60.; |
1746 | \& timer\->repeat = 60.; |
1668 | \& ev_timer_again (loop, timer); |
1747 | \& ev_timer_again (loop, timer); |
1669 | .Ve |
1748 | .Ve |
1670 | .Sp |
1749 | .Sp |
1671 | Each time there is some activity: |
1750 | Each time there is some activity: |
… | |
… | |
1740 | To start the timer, simply initialise the watcher and set \f(CW\*(C`last_activity\*(C'\fR |
1819 | To start the timer, simply initialise the watcher and set \f(CW\*(C`last_activity\*(C'\fR |
1741 | to the current time (meaning we just have some activity :), then call the |
1820 | to the current time (meaning we just have some activity :), then call the |
1742 | callback, which will \*(L"do the right thing\*(R" and start the timer: |
1821 | callback, which will \*(L"do the right thing\*(R" and start the timer: |
1743 | .Sp |
1822 | .Sp |
1744 | .Vb 3 |
1823 | .Vb 3 |
1745 | \& ev_timer_init (timer, callback); |
1824 | \& ev_init (timer, callback); |
1746 | \& last_activity = ev_now (loop); |
1825 | \& last_activity = ev_now (loop); |
1747 | \& callback (loop, timer, EV_TIMEOUT); |
1826 | \& callback (loop, timer, EV_TIMEOUT); |
1748 | .Ve |
1827 | .Ve |
1749 | .Sp |
1828 | .Sp |
1750 | And when there is some activity, simply store the current time in |
1829 | And when there is some activity, simply store the current time in |
… | |
… | |
1813 | .Ve |
1892 | .Ve |
1814 | .PP |
1893 | .PP |
1815 | If the event loop is suspended for a long time, you can also force an |
1894 | If the event loop is suspended for a long time, you can also force an |
1816 | update of the time returned by \f(CW\*(C`ev_now ()\*(C'\fR by calling \f(CW\*(C`ev_now_update |
1895 | update of the time returned by \f(CW\*(C`ev_now ()\*(C'\fR by calling \f(CW\*(C`ev_now_update |
1817 | ()\*(C'\fR. |
1896 | ()\*(C'\fR. |
|
|
1897 | .PP |
|
|
1898 | \fIThe special problems of suspended animation\fR |
|
|
1899 | .IX Subsection "The special problems of suspended animation" |
|
|
1900 | .PP |
|
|
1901 | When you leave the server world it is quite customary to hit machines that |
|
|
1902 | can suspend/hibernate \- what happens to the clocks during such a suspend? |
|
|
1903 | .PP |
|
|
1904 | Some quick tests made with a Linux 2.6.28 indicate that a suspend freezes |
|
|
1905 | all processes, while the clocks (\f(CW\*(C`times\*(C'\fR, \f(CW\*(C`CLOCK_MONOTONIC\*(C'\fR) continue |
|
|
1906 | to run until the system is suspended, but they will not advance while the |
|
|
1907 | system is suspended. That means, on resume, it will be as if the program |
|
|
1908 | was frozen for a few seconds, but the suspend time will not be counted |
|
|
1909 | towards \f(CW\*(C`ev_timer\*(C'\fR when a monotonic clock source is used. The real time |
|
|
1910 | clock advanced as expected, but if it is used as sole clocksource, then a |
|
|
1911 | long suspend would be detected as a time jump by libev, and timers would |
|
|
1912 | be adjusted accordingly. |
|
|
1913 | .PP |
|
|
1914 | I would not be surprised to see different behaviour in different between |
|
|
1915 | operating systems, \s-1OS\s0 versions or even different hardware. |
|
|
1916 | .PP |
|
|
1917 | The other form of suspend (job control, or sending a \s-1SIGSTOP\s0) will see a |
|
|
1918 | time jump in the monotonic clocks and the realtime clock. If the program |
|
|
1919 | is suspended for a very long time, and monotonic clock sources are in use, |
|
|
1920 | then you can expect \f(CW\*(C`ev_timer\*(C'\fRs to expire as the full suspension time |
|
|
1921 | will be counted towards the timers. When no monotonic clock source is in |
|
|
1922 | use, then libev will again assume a timejump and adjust accordingly. |
|
|
1923 | .PP |
|
|
1924 | It might be beneficial for this latter case to call \f(CW\*(C`ev_suspend\*(C'\fR |
|
|
1925 | and \f(CW\*(C`ev_resume\*(C'\fR in code that handles \f(CW\*(C`SIGTSTP\*(C'\fR, to at least get |
|
|
1926 | deterministic behaviour in this case (you can do nothing against |
|
|
1927 | \&\f(CW\*(C`SIGSTOP\*(C'\fR). |
1818 | .PP |
1928 | .PP |
1819 | \fIWatcher-Specific Functions and Data Members\fR |
1929 | \fIWatcher-Specific Functions and Data Members\fR |
1820 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1930 | .IX Subsection "Watcher-Specific Functions and Data Members" |
1821 | .IP "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" 4 |
1931 | .IP "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" 4 |
1822 | .IX Item "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" |
1932 | .IX Item "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" |
… | |
… | |
1847 | If the timer is repeating, either start it if necessary (with the |
1957 | If the timer is repeating, either start it if necessary (with the |
1848 | \&\f(CW\*(C`repeat\*(C'\fR value), or reset the running timer to the \f(CW\*(C`repeat\*(C'\fR value. |
1958 | \&\f(CW\*(C`repeat\*(C'\fR value), or reset the running timer to the \f(CW\*(C`repeat\*(C'\fR value. |
1849 | .Sp |
1959 | .Sp |
1850 | This sounds a bit complicated, see \*(L"Be smart about timeouts\*(R", above, for a |
1960 | This sounds a bit complicated, see \*(L"Be smart about timeouts\*(R", above, for a |
1851 | usage example. |
1961 | usage example. |
|
|
1962 | .IP "ev_timer_remaining (loop, ev_timer *)" 4 |
|
|
1963 | .IX Item "ev_timer_remaining (loop, ev_timer *)" |
|
|
1964 | Returns the remaining time until a timer fires. If the timer is active, |
|
|
1965 | then this time is relative to the current event loop time, otherwise it's |
|
|
1966 | the timeout value currently configured. |
|
|
1967 | .Sp |
|
|
1968 | That is, after an \f(CW\*(C`ev_timer_set (w, 5, 7)\*(C'\fR, \f(CW\*(C`ev_timer_remaining\*(C'\fR returns |
|
|
1969 | \&\f(CW5\fR. When the timer is started and one second passes, \f(CW\*(C`ev_timer_remain\*(C'\fR |
|
|
1970 | will return \f(CW4\fR. When the timer expires and is restarted, it will return |
|
|
1971 | roughly \f(CW7\fR (likely slightly less as callback invocation takes some time, |
|
|
1972 | too), and so on. |
1852 | .IP "ev_tstamp repeat [read\-write]" 4 |
1973 | .IP "ev_tstamp repeat [read\-write]" 4 |
1853 | .IX Item "ev_tstamp repeat [read-write]" |
1974 | .IX Item "ev_tstamp repeat [read-write]" |
1854 | The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out |
1975 | The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out |
1855 | or \f(CW\*(C`ev_timer_again\*(C'\fR is called, and determines the next timeout (if any), |
1976 | or \f(CW\*(C`ev_timer_again\*(C'\fR is called, and determines the next timeout (if any), |
1856 | which is also when any modifications are taken into account. |
1977 | which is also when any modifications are taken into account. |
… | |
… | |
1889 | \& |
2010 | \& |
1890 | \& // and in some piece of code that gets executed on any "activity": |
2011 | \& // and in some piece of code that gets executed on any "activity": |
1891 | \& // reset the timeout to start ticking again at 10 seconds |
2012 | \& // reset the timeout to start ticking again at 10 seconds |
1892 | \& ev_timer_again (&mytimer); |
2013 | \& ev_timer_again (&mytimer); |
1893 | .Ve |
2014 | .Ve |
1894 | .ie n .Sh """ev_periodic"" \- to cron or not to cron?" |
2015 | .ie n .SS """ev_periodic"" \- to cron or not to cron?" |
1895 | .el .Sh "\f(CWev_periodic\fP \- to cron or not to cron?" |
2016 | .el .SS "\f(CWev_periodic\fP \- to cron or not to cron?" |
1896 | .IX Subsection "ev_periodic - to cron or not to cron?" |
2017 | .IX Subsection "ev_periodic - to cron or not to cron?" |
1897 | Periodic watchers are also timers of a kind, but they are very versatile |
2018 | Periodic watchers are also timers of a kind, but they are very versatile |
1898 | (and unfortunately a bit complex). |
2019 | (and unfortunately a bit complex). |
1899 | .PP |
2020 | .PP |
1900 | Unlike \f(CW\*(C`ev_timer\*(C'\fR, periodic watchers are not based on real time (or |
2021 | Unlike \f(CW\*(C`ev_timer\*(C'\fR, periodic watchers are not based on real time (or |
… | |
… | |
2088 | \& ev_periodic hourly_tick; |
2209 | \& ev_periodic hourly_tick; |
2089 | \& ev_periodic_init (&hourly_tick, clock_cb, |
2210 | \& ev_periodic_init (&hourly_tick, clock_cb, |
2090 | \& fmod (ev_now (loop), 3600.), 3600., 0); |
2211 | \& fmod (ev_now (loop), 3600.), 3600., 0); |
2091 | \& ev_periodic_start (loop, &hourly_tick); |
2212 | \& ev_periodic_start (loop, &hourly_tick); |
2092 | .Ve |
2213 | .Ve |
2093 | .ie n .Sh """ev_signal"" \- signal me when a signal gets signalled!" |
2214 | .ie n .SS """ev_signal"" \- signal me when a signal gets signalled!" |
2094 | .el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled!" |
2215 | .el .SS "\f(CWev_signal\fP \- signal me when a signal gets signalled!" |
2095 | .IX Subsection "ev_signal - signal me when a signal gets signalled!" |
2216 | .IX Subsection "ev_signal - signal me when a signal gets signalled!" |
2096 | Signal watchers will trigger an event when the process receives a specific |
2217 | Signal watchers will trigger an event when the process receives a specific |
2097 | signal one or more times. Even though signals are very asynchronous, libev |
2218 | signal one or more times. Even though signals are very asynchronous, libev |
2098 | will try it's best to deliver signals synchronously, i.e. as part of the |
2219 | will try it's best to deliver signals synchronously, i.e. as part of the |
2099 | normal event processing, like any other event. |
2220 | normal event processing, like any other event. |
… | |
… | |
2143 | \& |
2264 | \& |
2144 | \& ev_signal signal_watcher; |
2265 | \& ev_signal signal_watcher; |
2145 | \& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
2266 | \& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
2146 | \& ev_signal_start (loop, &signal_watcher); |
2267 | \& ev_signal_start (loop, &signal_watcher); |
2147 | .Ve |
2268 | .Ve |
2148 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
2269 | .ie n .SS """ev_child"" \- watch out for process status changes" |
2149 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
2270 | .el .SS "\f(CWev_child\fP \- watch out for process status changes" |
2150 | .IX Subsection "ev_child - watch out for process status changes" |
2271 | .IX Subsection "ev_child - watch out for process status changes" |
2151 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
2272 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
2152 | some child status changes (most typically when a child of yours dies or |
2273 | some child status changes (most typically when a child of yours dies or |
2153 | exits). It is permissible to install a child watcher \fIafter\fR the child |
2274 | exits). It is permissible to install a child watcher \fIafter\fR the child |
2154 | has been forked (which implies it might have already exited), as long |
2275 | has been forked (which implies it might have already exited), as long |
2155 | as the event loop isn't entered (or is continued from a watcher), i.e., |
2276 | as the event loop isn't entered (or is continued from a watcher), i.e., |
2156 | forking and then immediately registering a watcher for the child is fine, |
2277 | forking and then immediately registering a watcher for the child is fine, |
2157 | but forking and registering a watcher a few event loop iterations later is |
2278 | but forking and registering a watcher a few event loop iterations later or |
2158 | not. |
2279 | in the next callback invocation is not. |
2159 | .PP |
2280 | .PP |
2160 | Only the default event loop is capable of handling signals, and therefore |
2281 | Only the default event loop is capable of handling signals, and therefore |
2161 | you can only register child watchers in the default event loop. |
2282 | you can only register child watchers in the default event loop. |
|
|
2283 | .PP |
|
|
2284 | Due to some design glitches inside libev, child watchers will always be |
|
|
2285 | handled at maximum priority (their priority is set to \f(CW\*(C`EV_MAXPRI\*(C'\fR by |
|
|
2286 | libev) |
2162 | .PP |
2287 | .PP |
2163 | \fIProcess Interaction\fR |
2288 | \fIProcess Interaction\fR |
2164 | .IX Subsection "Process Interaction" |
2289 | .IX Subsection "Process Interaction" |
2165 | .PP |
2290 | .PP |
2166 | Libev grabs \f(CW\*(C`SIGCHLD\*(C'\fR as soon as the default event loop is |
2291 | Libev grabs \f(CW\*(C`SIGCHLD\*(C'\fR as soon as the default event loop is |
… | |
… | |
2245 | \& { |
2370 | \& { |
2246 | \& ev_child_init (&cw, child_cb, pid, 0); |
2371 | \& ev_child_init (&cw, child_cb, pid, 0); |
2247 | \& ev_child_start (EV_DEFAULT_ &cw); |
2372 | \& ev_child_start (EV_DEFAULT_ &cw); |
2248 | \& } |
2373 | \& } |
2249 | .Ve |
2374 | .Ve |
2250 | .ie n .Sh """ev_stat"" \- did the file attributes just change?" |
2375 | .ie n .SS """ev_stat"" \- did the file attributes just change?" |
2251 | .el .Sh "\f(CWev_stat\fP \- did the file attributes just change?" |
2376 | .el .SS "\f(CWev_stat\fP \- did the file attributes just change?" |
2252 | .IX Subsection "ev_stat - did the file attributes just change?" |
2377 | .IX Subsection "ev_stat - did the file attributes just change?" |
2253 | This watches a file system path for attribute changes. That is, it calls |
2378 | This watches a file system path for attribute changes. That is, it calls |
2254 | \&\f(CW\*(C`stat\*(C'\fR on that path in regular intervals (or when the \s-1OS\s0 says it changed) |
2379 | \&\f(CW\*(C`stat\*(C'\fR on that path in regular intervals (or when the \s-1OS\s0 says it changed) |
2255 | and sees if it changed compared to the last time, invoking the callback if |
2380 | and sees if it changed compared to the last time, invoking the callback if |
2256 | it did. |
2381 | it did. |
… | |
… | |
2470 | \& ... |
2595 | \& ... |
2471 | \& ev_stat_init (&passwd, stat_cb, "/etc/passwd", 0.); |
2596 | \& ev_stat_init (&passwd, stat_cb, "/etc/passwd", 0.); |
2472 | \& ev_stat_start (loop, &passwd); |
2597 | \& ev_stat_start (loop, &passwd); |
2473 | \& ev_timer_init (&timer, timer_cb, 0., 1.02); |
2598 | \& ev_timer_init (&timer, timer_cb, 0., 1.02); |
2474 | .Ve |
2599 | .Ve |
2475 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
2600 | .ie n .SS """ev_idle"" \- when you've got nothing better to do..." |
2476 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." |
2601 | .el .SS "\f(CWev_idle\fP \- when you've got nothing better to do..." |
2477 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
2602 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
2478 | Idle watchers trigger events when no other events of the same or higher |
2603 | Idle watchers trigger events when no other events of the same or higher |
2479 | priority are pending (prepare, check and other idle watchers do not count |
2604 | priority are pending (prepare, check and other idle watchers do not count |
2480 | as receiving \*(L"events\*(R"). |
2605 | as receiving \*(L"events\*(R"). |
2481 | .PP |
2606 | .PP |
… | |
… | |
2517 | \& // no longer anything immediate to do. |
2642 | \& // no longer anything immediate to do. |
2518 | \& } |
2643 | \& } |
2519 | \& |
2644 | \& |
2520 | \& ev_idle *idle_watcher = malloc (sizeof (ev_idle)); |
2645 | \& ev_idle *idle_watcher = malloc (sizeof (ev_idle)); |
2521 | \& ev_idle_init (idle_watcher, idle_cb); |
2646 | \& ev_idle_init (idle_watcher, idle_cb); |
2522 | \& ev_idle_start (loop, idle_cb); |
2647 | \& ev_idle_start (loop, idle_watcher); |
2523 | .Ve |
2648 | .Ve |
2524 | .ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop!" |
2649 | .ie n .SS """ev_prepare"" and ""ev_check"" \- customise your event loop!" |
2525 | .el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop!" |
2650 | .el .SS "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop!" |
2526 | .IX Subsection "ev_prepare and ev_check - customise your event loop!" |
2651 | .IX Subsection "ev_prepare and ev_check - customise your event loop!" |
2527 | Prepare and check watchers are usually (but not always) used in pairs: |
2652 | Prepare and check watchers are usually (but not always) used in pairs: |
2528 | prepare watchers get invoked before the process blocks and check watchers |
2653 | prepare watchers get invoked before the process blocks and check watchers |
2529 | afterwards. |
2654 | afterwards. |
2530 | .PP |
2655 | .PP |
… | |
… | |
2620 | \& struct pollfd fds [nfd]; |
2745 | \& struct pollfd fds [nfd]; |
2621 | \& // actual code will need to loop here and realloc etc. |
2746 | \& // actual code will need to loop here and realloc etc. |
2622 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
2747 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
2623 | \& |
2748 | \& |
2624 | \& /* the callback is illegal, but won\*(Aqt be called as we stop during check */ |
2749 | \& /* the callback is illegal, but won\*(Aqt be called as we stop during check */ |
2625 | \& ev_timer_init (&tw, 0, timeout * 1e\-3); |
2750 | \& ev_timer_init (&tw, 0, timeout * 1e\-3, 0.); |
2626 | \& ev_timer_start (loop, &tw); |
2751 | \& ev_timer_start (loop, &tw); |
2627 | \& |
2752 | \& |
2628 | \& // create one ev_io per pollfd |
2753 | \& // create one ev_io per pollfd |
2629 | \& for (int i = 0; i < nfd; ++i) |
2754 | \& for (int i = 0; i < nfd; ++i) |
2630 | \& { |
2755 | \& { |
… | |
… | |
2721 | \& ev_io_stop (EV_A_ iow [n]); |
2846 | \& ev_io_stop (EV_A_ iow [n]); |
2722 | \& |
2847 | \& |
2723 | \& return got_events; |
2848 | \& return got_events; |
2724 | \& } |
2849 | \& } |
2725 | .Ve |
2850 | .Ve |
2726 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
2851 | .ie n .SS """ev_embed"" \- when one backend isn't enough..." |
2727 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
2852 | .el .SS "\f(CWev_embed\fP \- when one backend isn't enough..." |
2728 | .IX Subsection "ev_embed - when one backend isn't enough..." |
2853 | .IX Subsection "ev_embed - when one backend isn't enough..." |
2729 | This is a rather advanced watcher type that lets you embed one event loop |
2854 | This is a rather advanced watcher type that lets you embed one event loop |
2730 | into another (currently only \f(CW\*(C`ev_io\*(C'\fR events are supported in the embedded |
2855 | into another (currently only \f(CW\*(C`ev_io\*(C'\fR events are supported in the embedded |
2731 | loop, other types of watchers might be handled in a delayed or incorrect |
2856 | loop, other types of watchers might be handled in a delayed or incorrect |
2732 | fashion and must not be used). |
2857 | fashion and must not be used). |
… | |
… | |
2854 | \& if (!loop_socket) |
2979 | \& if (!loop_socket) |
2855 | \& loop_socket = loop; |
2980 | \& loop_socket = loop; |
2856 | \& |
2981 | \& |
2857 | \& // now use loop_socket for all sockets, and loop for everything else |
2982 | \& // now use loop_socket for all sockets, and loop for everything else |
2858 | .Ve |
2983 | .Ve |
2859 | .ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork" |
2984 | .ie n .SS """ev_fork"" \- the audacity to resume the event loop after a fork" |
2860 | .el .Sh "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork" |
2985 | .el .SS "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork" |
2861 | .IX Subsection "ev_fork - the audacity to resume the event loop after a fork" |
2986 | .IX Subsection "ev_fork - the audacity to resume the event loop after a fork" |
2862 | Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because |
2987 | Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because |
2863 | whoever is a good citizen cared to tell libev about it by calling |
2988 | whoever is a good citizen cared to tell libev about it by calling |
2864 | \&\f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the |
2989 | \&\f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the |
2865 | event loop blocks next and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called, |
2990 | event loop blocks next and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called, |
… | |
… | |
2906 | .IP "ev_fork_init (ev_signal *, callback)" 4 |
3031 | .IP "ev_fork_init (ev_signal *, callback)" 4 |
2907 | .IX Item "ev_fork_init (ev_signal *, callback)" |
3032 | .IX Item "ev_fork_init (ev_signal *, callback)" |
2908 | Initialises and configures the fork watcher \- it has no parameters of any |
3033 | Initialises and configures the fork watcher \- it has no parameters of any |
2909 | kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless, |
3034 | kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless, |
2910 | believe me. |
3035 | believe me. |
2911 | .ie n .Sh """ev_async"" \- how to wake up another event loop" |
3036 | .ie n .SS """ev_async"" \- how to wake up another event loop" |
2912 | .el .Sh "\f(CWev_async\fP \- how to wake up another event loop" |
3037 | .el .SS "\f(CWev_async\fP \- how to wake up another event loop" |
2913 | .IX Subsection "ev_async - how to wake up another event loop" |
3038 | .IX Subsection "ev_async - how to wake up another event loop" |
2914 | In general, you cannot use an \f(CW\*(C`ev_loop\*(C'\fR from multiple threads or other |
3039 | In general, you cannot use an \f(CW\*(C`ev_loop\*(C'\fR from multiple threads or other |
2915 | asynchronous sources such as signal handlers (as opposed to multiple event |
3040 | asynchronous sources such as signal handlers (as opposed to multiple event |
2916 | loops \- those are of course safe to use in different threads). |
3041 | loops \- those are of course safe to use in different threads). |
2917 | .PP |
3042 | .PP |
… | |
… | |
3155 | need one additional pointer for context. If you need support for other |
3280 | need one additional pointer for context. If you need support for other |
3156 | types of functors please contact the author (preferably after implementing |
3281 | types of functors please contact the author (preferably after implementing |
3157 | it). |
3282 | it). |
3158 | .PP |
3283 | .PP |
3159 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
3284 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
3160 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
3285 | .ie n .IP """ev::READ"", ""ev::WRITE"" etc." 4 |
3161 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
3286 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
3162 | .IX Item "ev::READ, ev::WRITE etc." |
3287 | .IX Item "ev::READ, ev::WRITE etc." |
3163 | These are just enum values with the same values as the \f(CW\*(C`EV_READ\*(C'\fR etc. |
3288 | These are just enum values with the same values as the \f(CW\*(C`EV_READ\*(C'\fR etc. |
3164 | macros from \fIev.h\fR. |
3289 | macros from \fIev.h\fR. |
3165 | .ie n .IP """ev::tstamp""\fR, \f(CW""ev::now""" 4 |
3290 | .ie n .IP """ev::tstamp"", ""ev::now""" 4 |
3166 | .el .IP "\f(CWev::tstamp\fR, \f(CWev::now\fR" 4 |
3291 | .el .IP "\f(CWev::tstamp\fR, \f(CWev::now\fR" 4 |
3167 | .IX Item "ev::tstamp, ev::now" |
3292 | .IX Item "ev::tstamp, ev::now" |
3168 | Aliases to the same types/functions as with the \f(CW\*(C`ev_\*(C'\fR prefix. |
3293 | Aliases to the same types/functions as with the \f(CW\*(C`ev_\*(C'\fR prefix. |
3169 | .ie n .IP """ev::io""\fR, \f(CW""ev::timer""\fR, \f(CW""ev::periodic""\fR, \f(CW""ev::idle""\fR, \f(CW""ev::sig"" etc." 4 |
3294 | .ie n .IP """ev::io"", ""ev::timer"", ""ev::periodic"", ""ev::idle"", ""ev::sig"" etc." 4 |
3170 | .el .IP "\f(CWev::io\fR, \f(CWev::timer\fR, \f(CWev::periodic\fR, \f(CWev::idle\fR, \f(CWev::sig\fR etc." 4 |
3295 | .el .IP "\f(CWev::io\fR, \f(CWev::timer\fR, \f(CWev::periodic\fR, \f(CWev::idle\fR, \f(CWev::sig\fR etc." 4 |
3171 | .IX Item "ev::io, ev::timer, ev::periodic, ev::idle, ev::sig etc." |
3296 | .IX Item "ev::io, ev::timer, ev::periodic, ev::idle, ev::sig etc." |
3172 | For each \f(CW\*(C`ev_TYPE\*(C'\fR watcher in \fIev.h\fR there is a corresponding class of |
3297 | For each \f(CW\*(C`ev_TYPE\*(C'\fR watcher in \fIev.h\fR there is a corresponding class of |
3173 | the same name in the \f(CW\*(C`ev\*(C'\fR namespace, with the exception of \f(CW\*(C`ev_signal\*(C'\fR |
3298 | the same name in the \f(CW\*(C`ev\*(C'\fR namespace, with the exception of \f(CW\*(C`ev_signal\*(C'\fR |
3174 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
3299 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
… | |
… | |
3284 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
3409 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
3285 | constructor already stores the event loop. |
3410 | constructor already stores the event loop. |
3286 | .IP "w\->stop ()" 4 |
3411 | .IP "w\->stop ()" 4 |
3287 | .IX Item "w->stop ()" |
3412 | .IX Item "w->stop ()" |
3288 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
3413 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
3289 | .ie n .IP "w\->again () (""ev::timer""\fR, \f(CW""ev::periodic"" only)" 4 |
3414 | .ie n .IP "w\->again () (""ev::timer"", ""ev::periodic"" only)" 4 |
3290 | .el .IP "w\->again () (\f(CWev::timer\fR, \f(CWev::periodic\fR only)" 4 |
3415 | .el .IP "w\->again () (\f(CWev::timer\fR, \f(CWev::periodic\fR only)" 4 |
3291 | .IX Item "w->again () (ev::timer, ev::periodic only)" |
3416 | .IX Item "w->again () (ev::timer, ev::periodic only)" |
3292 | For \f(CW\*(C`ev::timer\*(C'\fR and \f(CW\*(C`ev::periodic\*(C'\fR, this invokes the corresponding |
3417 | For \f(CW\*(C`ev::timer\*(C'\fR and \f(CW\*(C`ev::periodic\*(C'\fR, this invokes the corresponding |
3293 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
3418 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
3294 | .ie n .IP "w\->sweep () (""ev::embed"" only)" 4 |
3419 | .ie n .IP "w\->sweep () (""ev::embed"" only)" 4 |
… | |
… | |
3369 | of which is \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) |
3494 | of which is \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) |
3370 | functions and callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
3495 | functions and callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
3371 | .PP |
3496 | .PP |
3372 | To make it easier to write programs that cope with either variant, the |
3497 | To make it easier to write programs that cope with either variant, the |
3373 | following macros are defined: |
3498 | following macros are defined: |
3374 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
3499 | .ie n .IP """EV_A"", ""EV_A_""" 4 |
3375 | .el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4 |
3500 | .el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4 |
3376 | .IX Item "EV_A, EV_A_" |
3501 | .IX Item "EV_A, EV_A_" |
3377 | This provides the loop \fIargument\fR for functions, if one is required (\*(L"ev |
3502 | This provides the loop \fIargument\fR for functions, if one is required (\*(L"ev |
3378 | loop argument\*(R"). The \f(CW\*(C`EV_A\*(C'\fR form is used when this is the sole argument, |
3503 | loop argument\*(R"). The \f(CW\*(C`EV_A\*(C'\fR form is used when this is the sole argument, |
3379 | \&\f(CW\*(C`EV_A_\*(C'\fR is used when other arguments are following. Example: |
3504 | \&\f(CW\*(C`EV_A_\*(C'\fR is used when other arguments are following. Example: |
… | |
… | |
3384 | \& ev_loop (EV_A_ 0); |
3509 | \& ev_loop (EV_A_ 0); |
3385 | .Ve |
3510 | .Ve |
3386 | .Sp |
3511 | .Sp |
3387 | It assumes the variable \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR is in scope, |
3512 | It assumes the variable \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR is in scope, |
3388 | which is often provided by the following macro. |
3513 | which is often provided by the following macro. |
3389 | .ie n .IP """EV_P""\fR, \f(CW""EV_P_""" 4 |
3514 | .ie n .IP """EV_P"", ""EV_P_""" 4 |
3390 | .el .IP "\f(CWEV_P\fR, \f(CWEV_P_\fR" 4 |
3515 | .el .IP "\f(CWEV_P\fR, \f(CWEV_P_\fR" 4 |
3391 | .IX Item "EV_P, EV_P_" |
3516 | .IX Item "EV_P, EV_P_" |
3392 | This provides the loop \fIparameter\fR for functions, if one is required (\*(L"ev |
3517 | This provides the loop \fIparameter\fR for functions, if one is required (\*(L"ev |
3393 | loop parameter\*(R"). The \f(CW\*(C`EV_P\*(C'\fR form is used when this is the sole parameter, |
3518 | loop parameter\*(R"). The \f(CW\*(C`EV_P\*(C'\fR form is used when this is the sole parameter, |
3394 | \&\f(CW\*(C`EV_P_\*(C'\fR is used when other parameters are following. Example: |
3519 | \&\f(CW\*(C`EV_P_\*(C'\fR is used when other parameters are following. Example: |
… | |
… | |
3401 | \& static void cb (EV_P_ ev_timer *w, int revents) |
3526 | \& static void cb (EV_P_ ev_timer *w, int revents) |
3402 | .Ve |
3527 | .Ve |
3403 | .Sp |
3528 | .Sp |
3404 | It declares a parameter \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR, quite |
3529 | It declares a parameter \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR, quite |
3405 | suitable for use with \f(CW\*(C`EV_A\*(C'\fR. |
3530 | suitable for use with \f(CW\*(C`EV_A\*(C'\fR. |
3406 | .ie n .IP """EV_DEFAULT""\fR, \f(CW""EV_DEFAULT_""" 4 |
3531 | .ie n .IP """EV_DEFAULT"", ""EV_DEFAULT_""" 4 |
3407 | .el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4 |
3532 | .el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4 |
3408 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
3533 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
3409 | Similar to the other two macros, this gives you the value of the default |
3534 | Similar to the other two macros, this gives you the value of the default |
3410 | loop, if multiple loops are supported (\*(L"ev loop default\*(R"). |
3535 | loop, if multiple loops are supported (\*(L"ev loop default\*(R"). |
3411 | .ie n .IP """EV_DEFAULT_UC""\fR, \f(CW""EV_DEFAULT_UC_""" 4 |
3536 | .ie n .IP """EV_DEFAULT_UC"", ""EV_DEFAULT_UC_""" 4 |
3412 | .el .IP "\f(CWEV_DEFAULT_UC\fR, \f(CWEV_DEFAULT_UC_\fR" 4 |
3537 | .el .IP "\f(CWEV_DEFAULT_UC\fR, \f(CWEV_DEFAULT_UC_\fR" 4 |
3413 | .IX Item "EV_DEFAULT_UC, EV_DEFAULT_UC_" |
3538 | .IX Item "EV_DEFAULT_UC, EV_DEFAULT_UC_" |
3414 | Usage identical to \f(CW\*(C`EV_DEFAULT\*(C'\fR and \f(CW\*(C`EV_DEFAULT_\*(C'\fR, but requires that the |
3539 | Usage identical to \f(CW\*(C`EV_DEFAULT\*(C'\fR and \f(CW\*(C`EV_DEFAULT_\*(C'\fR, but requires that the |
3415 | default loop has been initialised (\f(CW\*(C`UC\*(C'\fR == unchecked). Their behaviour |
3540 | default loop has been initialised (\f(CW\*(C`UC\*(C'\fR == unchecked). Their behaviour |
3416 | is undefined when the default loop has not been initialised by a previous |
3541 | is undefined when the default loop has not been initialised by a previous |
… | |
… | |
3444 | .PP |
3569 | .PP |
3445 | The goal is to enable you to just copy the necessary files into your |
3570 | The goal is to enable you to just copy the necessary files into your |
3446 | source directory without having to change even a single line in them, so |
3571 | source directory without having to change even a single line in them, so |
3447 | you can easily upgrade by simply copying (or having a checked-out copy of |
3572 | you can easily upgrade by simply copying (or having a checked-out copy of |
3448 | libev somewhere in your source tree). |
3573 | libev somewhere in your source tree). |
3449 | .Sh "\s-1FILESETS\s0" |
3574 | .SS "\s-1FILESETS\s0" |
3450 | .IX Subsection "FILESETS" |
3575 | .IX Subsection "FILESETS" |
3451 | Depending on what features you need you need to include one or more sets of files |
3576 | Depending on what features you need you need to include one or more sets of files |
3452 | in your application. |
3577 | in your application. |
3453 | .PP |
3578 | .PP |
3454 | \fI\s-1CORE\s0 \s-1EVENT\s0 \s-1LOOP\s0\fR |
3579 | \fI\s-1CORE\s0 \s-1EVENT\s0 \s-1LOOP\s0\fR |
… | |
… | |
3533 | For this of course you need the m4 file: |
3658 | For this of course you need the m4 file: |
3534 | .PP |
3659 | .PP |
3535 | .Vb 1 |
3660 | .Vb 1 |
3536 | \& libev.m4 |
3661 | \& libev.m4 |
3537 | .Ve |
3662 | .Ve |
3538 | .Sh "\s-1PREPROCESSOR\s0 \s-1SYMBOLS/MACROS\s0" |
3663 | .SS "\s-1PREPROCESSOR\s0 \s-1SYMBOLS/MACROS\s0" |
3539 | .IX Subsection "PREPROCESSOR SYMBOLS/MACROS" |
3664 | .IX Subsection "PREPROCESSOR SYMBOLS/MACROS" |
3540 | Libev can be configured via a variety of preprocessor symbols you have to |
3665 | Libev can be configured via a variety of preprocessor symbols you have to |
3541 | define before including any of its files. The default in the absence of |
3666 | define before including any of its files. The default in the absence of |
3542 | autoconf is documented for every option. |
3667 | autoconf is documented for every option. |
3543 | .IP "\s-1EV_STANDALONE\s0" 4 |
3668 | .IP "\s-1EV_STANDALONE\s0" 4 |
… | |
… | |
3742 | If undefined or defined to be \f(CW1\fR, then async watchers are supported. If |
3867 | If undefined or defined to be \f(CW1\fR, then async watchers are supported. If |
3743 | defined to be \f(CW0\fR, then they are not. |
3868 | defined to be \f(CW0\fR, then they are not. |
3744 | .IP "\s-1EV_MINIMAL\s0" 4 |
3869 | .IP "\s-1EV_MINIMAL\s0" 4 |
3745 | .IX Item "EV_MINIMAL" |
3870 | .IX Item "EV_MINIMAL" |
3746 | If you need to shave off some kilobytes of code at the expense of some |
3871 | If you need to shave off some kilobytes of code at the expense of some |
3747 | speed, define this symbol to \f(CW1\fR. Currently this is used to override some |
3872 | speed (but with the full \s-1API\s0), define this symbol to \f(CW1\fR. Currently this |
3748 | inlining decisions, saves roughly 30% code size on amd64. It also selects a |
3873 | is used to override some inlining decisions, saves roughly 30% code size |
3749 | much smaller 2\-heap for timer management over the default 4\-heap. |
3874 | on amd64. It also selects a much smaller 2\-heap for timer management over |
|
|
3875 | the default 4\-heap. |
|
|
3876 | .Sp |
|
|
3877 | You can save even more by disabling watcher types you do not need |
|
|
3878 | and setting \f(CW\*(C`EV_MAXPRI\*(C'\fR == \f(CW\*(C`EV_MINPRI\*(C'\fR. Also, disabling \f(CW\*(C`assert\*(C'\fR |
|
|
3879 | (\f(CW\*(C`\-DNDEBUG\*(C'\fR) will usually reduce code size a lot. |
|
|
3880 | .Sp |
|
|
3881 | Defining \f(CW\*(C`EV_MINIMAL\*(C'\fR to \f(CW2\fR will additionally reduce the core \s-1API\s0 to |
|
|
3882 | provide a bare-bones event library. See \f(CW\*(C`ev.h\*(C'\fR for details on what parts |
|
|
3883 | of the \s-1API\s0 are still available, and do not complain if this subset changes |
|
|
3884 | over time. |
3750 | .IP "\s-1EV_PID_HASHSIZE\s0" 4 |
3885 | .IP "\s-1EV_PID_HASHSIZE\s0" 4 |
3751 | .IX Item "EV_PID_HASHSIZE" |
3886 | .IX Item "EV_PID_HASHSIZE" |
3752 | \&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by |
3887 | \&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by |
3753 | pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more |
3888 | pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more |
3754 | than enough. If you need to manage thousands of children you might want to |
3889 | than enough. If you need to manage thousands of children you might want to |
… | |
… | |
3818 | and the way callbacks are invoked and set. Must expand to a struct member |
3953 | and the way callbacks are invoked and set. Must expand to a struct member |
3819 | definition and a statement, respectively. See the \fIev.h\fR header file for |
3954 | definition and a statement, respectively. See the \fIev.h\fR header file for |
3820 | their default definitions. One possible use for overriding these is to |
3955 | their default definitions. One possible use for overriding these is to |
3821 | avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use |
3956 | avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use |
3822 | method calls instead of plain function calls in \*(C+. |
3957 | method calls instead of plain function calls in \*(C+. |
3823 | .Sh "\s-1EXPORTED\s0 \s-1API\s0 \s-1SYMBOLS\s0" |
3958 | .SS "\s-1EXPORTED\s0 \s-1API\s0 \s-1SYMBOLS\s0" |
3824 | .IX Subsection "EXPORTED API SYMBOLS" |
3959 | .IX Subsection "EXPORTED API SYMBOLS" |
3825 | If you need to re-export the \s-1API\s0 (e.g. via a \s-1DLL\s0) and you need a list of |
3960 | If you need to re-export the \s-1API\s0 (e.g. via a \s-1DLL\s0) and you need a list of |
3826 | exported symbols, you can use the provided \fISymbol.*\fR files which list |
3961 | exported symbols, you can use the provided \fISymbol.*\fR files which list |
3827 | all public symbols, one per line: |
3962 | all public symbols, one per line: |
3828 | .PP |
3963 | .PP |
… | |
… | |
3848 | \& #define ev_backend myprefix_ev_backend |
3983 | \& #define ev_backend myprefix_ev_backend |
3849 | \& #define ev_check_start myprefix_ev_check_start |
3984 | \& #define ev_check_start myprefix_ev_check_start |
3850 | \& #define ev_check_stop myprefix_ev_check_stop |
3985 | \& #define ev_check_stop myprefix_ev_check_stop |
3851 | \& ... |
3986 | \& ... |
3852 | .Ve |
3987 | .Ve |
3853 | .Sh "\s-1EXAMPLES\s0" |
3988 | .SS "\s-1EXAMPLES\s0" |
3854 | .IX Subsection "EXAMPLES" |
3989 | .IX Subsection "EXAMPLES" |
3855 | For a real-world example of a program the includes libev |
3990 | For a real-world example of a program the includes libev |
3856 | verbatim, you can have a look at the \s-1EV\s0 perl module |
3991 | verbatim, you can have a look at the \s-1EV\s0 perl module |
3857 | (<http://software.schmorp.de/pkg/EV.html>). It has the libev files in |
3992 | (<http://software.schmorp.de/pkg/EV.html>). It has the libev files in |
3858 | the \fIlibev/\fR subdirectory and includes them in the \fI\s-1EV/EVAPI\s0.h\fR (public |
3993 | the \fIlibev/\fR subdirectory and includes them in the \fI\s-1EV/EVAPI\s0.h\fR (public |
… | |
… | |
3883 | \& #include "ev_cpp.h" |
4018 | \& #include "ev_cpp.h" |
3884 | \& #include "ev.c" |
4019 | \& #include "ev.c" |
3885 | .Ve |
4020 | .Ve |
3886 | .SH "INTERACTION WITH OTHER PROGRAMS OR LIBRARIES" |
4021 | .SH "INTERACTION WITH OTHER PROGRAMS OR LIBRARIES" |
3887 | .IX Header "INTERACTION WITH OTHER PROGRAMS OR LIBRARIES" |
4022 | .IX Header "INTERACTION WITH OTHER PROGRAMS OR LIBRARIES" |
3888 | .Sh "\s-1THREADS\s0 \s-1AND\s0 \s-1COROUTINES\s0" |
4023 | .SS "\s-1THREADS\s0 \s-1AND\s0 \s-1COROUTINES\s0" |
3889 | .IX Subsection "THREADS AND COROUTINES" |
4024 | .IX Subsection "THREADS AND COROUTINES" |
3890 | \fI\s-1THREADS\s0\fR |
4025 | \fI\s-1THREADS\s0\fR |
3891 | .IX Subsection "THREADS" |
4026 | .IX Subsection "THREADS" |
3892 | .PP |
4027 | .PP |
3893 | All libev functions are reentrant and thread-safe unless explicitly |
4028 | All libev functions are reentrant and thread-safe unless explicitly |
… | |
… | |
3939 | An example use would be to communicate signals or other events that only |
4074 | An example use would be to communicate signals or other events that only |
3940 | work in the default loop by registering the signal watcher with the |
4075 | work in the default loop by registering the signal watcher with the |
3941 | default loop and triggering an \f(CW\*(C`ev_async\*(C'\fR watcher from the default loop |
4076 | default loop and triggering an \f(CW\*(C`ev_async\*(C'\fR watcher from the default loop |
3942 | watcher callback into the event loop interested in the signal. |
4077 | watcher callback into the event loop interested in the signal. |
3943 | .PP |
4078 | .PP |
|
|
4079 | \s-1THREAD\s0 \s-1LOCKING\s0 \s-1EXAMPLE\s0 |
|
|
4080 | .IX Subsection "THREAD LOCKING EXAMPLE" |
|
|
4081 | .PP |
|
|
4082 | Here is a fictitious example of how to run an event loop in a different |
|
|
4083 | thread than where callbacks are being invoked and watchers are |
|
|
4084 | created/added/removed. |
|
|
4085 | .PP |
|
|
4086 | For a real-world example, see the \f(CW\*(C`EV::Loop::Async\*(C'\fR perl module, |
|
|
4087 | which uses exactly this technique (which is suited for many high-level |
|
|
4088 | languages). |
|
|
4089 | .PP |
|
|
4090 | The example uses a pthread mutex to protect the loop data, a condition |
|
|
4091 | variable to wait for callback invocations, an async watcher to notify the |
|
|
4092 | event loop thread and an unspecified mechanism to wake up the main thread. |
|
|
4093 | .PP |
|
|
4094 | First, you need to associate some data with the event loop: |
|
|
4095 | .PP |
|
|
4096 | .Vb 6 |
|
|
4097 | \& typedef struct { |
|
|
4098 | \& mutex_t lock; /* global loop lock */ |
|
|
4099 | \& ev_async async_w; |
|
|
4100 | \& thread_t tid; |
|
|
4101 | \& cond_t invoke_cv; |
|
|
4102 | \& } userdata; |
|
|
4103 | \& |
|
|
4104 | \& void prepare_loop (EV_P) |
|
|
4105 | \& { |
|
|
4106 | \& // for simplicity, we use a static userdata struct. |
|
|
4107 | \& static userdata u; |
|
|
4108 | \& |
|
|
4109 | \& ev_async_init (&u\->async_w, async_cb); |
|
|
4110 | \& ev_async_start (EV_A_ &u\->async_w); |
|
|
4111 | \& |
|
|
4112 | \& pthread_mutex_init (&u\->lock, 0); |
|
|
4113 | \& pthread_cond_init (&u\->invoke_cv, 0); |
|
|
4114 | \& |
|
|
4115 | \& // now associate this with the loop |
|
|
4116 | \& ev_set_userdata (EV_A_ u); |
|
|
4117 | \& ev_set_invoke_pending_cb (EV_A_ l_invoke); |
|
|
4118 | \& ev_set_loop_release_cb (EV_A_ l_release, l_acquire); |
|
|
4119 | \& |
|
|
4120 | \& // then create the thread running ev_loop |
|
|
4121 | \& pthread_create (&u\->tid, 0, l_run, EV_A); |
|
|
4122 | \& } |
|
|
4123 | .Ve |
|
|
4124 | .PP |
|
|
4125 | The callback for the \f(CW\*(C`ev_async\*(C'\fR watcher does nothing: the watcher is used |
|
|
4126 | solely to wake up the event loop so it takes notice of any new watchers |
|
|
4127 | that might have been added: |
|
|
4128 | .PP |
|
|
4129 | .Vb 5 |
|
|
4130 | \& static void |
|
|
4131 | \& async_cb (EV_P_ ev_async *w, int revents) |
|
|
4132 | \& { |
|
|
4133 | \& // just used for the side effects |
|
|
4134 | \& } |
|
|
4135 | .Ve |
|
|
4136 | .PP |
|
|
4137 | The \f(CW\*(C`l_release\*(C'\fR and \f(CW\*(C`l_acquire\*(C'\fR callbacks simply unlock/lock the mutex |
|
|
4138 | protecting the loop data, respectively. |
|
|
4139 | .PP |
|
|
4140 | .Vb 6 |
|
|
4141 | \& static void |
|
|
4142 | \& l_release (EV_P) |
|
|
4143 | \& { |
|
|
4144 | \& userdata *u = ev_userdata (EV_A); |
|
|
4145 | \& pthread_mutex_unlock (&u\->lock); |
|
|
4146 | \& } |
|
|
4147 | \& |
|
|
4148 | \& static void |
|
|
4149 | \& l_acquire (EV_P) |
|
|
4150 | \& { |
|
|
4151 | \& userdata *u = ev_userdata (EV_A); |
|
|
4152 | \& pthread_mutex_lock (&u\->lock); |
|
|
4153 | \& } |
|
|
4154 | .Ve |
|
|
4155 | .PP |
|
|
4156 | The event loop thread first acquires the mutex, and then jumps straight |
|
|
4157 | into \f(CW\*(C`ev_loop\*(C'\fR: |
|
|
4158 | .PP |
|
|
4159 | .Vb 4 |
|
|
4160 | \& void * |
|
|
4161 | \& l_run (void *thr_arg) |
|
|
4162 | \& { |
|
|
4163 | \& struct ev_loop *loop = (struct ev_loop *)thr_arg; |
|
|
4164 | \& |
|
|
4165 | \& l_acquire (EV_A); |
|
|
4166 | \& pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0); |
|
|
4167 | \& ev_loop (EV_A_ 0); |
|
|
4168 | \& l_release (EV_A); |
|
|
4169 | \& |
|
|
4170 | \& return 0; |
|
|
4171 | \& } |
|
|
4172 | .Ve |
|
|
4173 | .PP |
|
|
4174 | Instead of invoking all pending watchers, the \f(CW\*(C`l_invoke\*(C'\fR callback will |
|
|
4175 | signal the main thread via some unspecified mechanism (signals? pipe |
|
|
4176 | writes? \f(CW\*(C`Async::Interrupt\*(C'\fR?) and then waits until all pending watchers |
|
|
4177 | have been called (in a while loop because a) spurious wakeups are possible |
|
|
4178 | and b) skipping inter-thread-communication when there are no pending |
|
|
4179 | watchers is very beneficial): |
|
|
4180 | .PP |
|
|
4181 | .Vb 4 |
|
|
4182 | \& static void |
|
|
4183 | \& l_invoke (EV_P) |
|
|
4184 | \& { |
|
|
4185 | \& userdata *u = ev_userdata (EV_A); |
|
|
4186 | \& |
|
|
4187 | \& while (ev_pending_count (EV_A)) |
|
|
4188 | \& { |
|
|
4189 | \& wake_up_other_thread_in_some_magic_or_not_so_magic_way (); |
|
|
4190 | \& pthread_cond_wait (&u\->invoke_cv, &u\->lock); |
|
|
4191 | \& } |
|
|
4192 | \& } |
|
|
4193 | .Ve |
|
|
4194 | .PP |
|
|
4195 | Now, whenever the main thread gets told to invoke pending watchers, it |
|
|
4196 | will grab the lock, call \f(CW\*(C`ev_invoke_pending\*(C'\fR and then signal the loop |
|
|
4197 | thread to continue: |
|
|
4198 | .PP |
|
|
4199 | .Vb 4 |
|
|
4200 | \& static void |
|
|
4201 | \& real_invoke_pending (EV_P) |
|
|
4202 | \& { |
|
|
4203 | \& userdata *u = ev_userdata (EV_A); |
|
|
4204 | \& |
|
|
4205 | \& pthread_mutex_lock (&u\->lock); |
|
|
4206 | \& ev_invoke_pending (EV_A); |
|
|
4207 | \& pthread_cond_signal (&u\->invoke_cv); |
|
|
4208 | \& pthread_mutex_unlock (&u\->lock); |
|
|
4209 | \& } |
|
|
4210 | .Ve |
|
|
4211 | .PP |
|
|
4212 | Whenever you want to start/stop a watcher or do other modifications to an |
|
|
4213 | event loop, you will now have to lock: |
|
|
4214 | .PP |
|
|
4215 | .Vb 2 |
|
|
4216 | \& ev_timer timeout_watcher; |
|
|
4217 | \& userdata *u = ev_userdata (EV_A); |
|
|
4218 | \& |
|
|
4219 | \& ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.); |
|
|
4220 | \& |
|
|
4221 | \& pthread_mutex_lock (&u\->lock); |
|
|
4222 | \& ev_timer_start (EV_A_ &timeout_watcher); |
|
|
4223 | \& ev_async_send (EV_A_ &u\->async_w); |
|
|
4224 | \& pthread_mutex_unlock (&u\->lock); |
|
|
4225 | .Ve |
|
|
4226 | .PP |
|
|
4227 | Note that sending the \f(CW\*(C`ev_async\*(C'\fR watcher is required because otherwise |
|
|
4228 | an event loop currently blocking in the kernel will have no knowledge |
|
|
4229 | about the newly added timer. By waking up the loop it will pick up any new |
|
|
4230 | watchers in the next event loop iteration. |
|
|
4231 | .PP |
3944 | \fI\s-1COROUTINES\s0\fR |
4232 | \fI\s-1COROUTINES\s0\fR |
3945 | .IX Subsection "COROUTINES" |
4233 | .IX Subsection "COROUTINES" |
3946 | .PP |
4234 | .PP |
3947 | Libev is very accommodating to coroutines (\*(L"cooperative threads\*(R"): |
4235 | Libev is very accommodating to coroutines (\*(L"cooperative threads\*(R"): |
3948 | libev fully supports nesting calls to its functions from different |
4236 | libev fully supports nesting calls to its functions from different |
3949 | coroutines (e.g. you can call \f(CW\*(C`ev_loop\*(C'\fR on the same loop from two |
4237 | coroutines (e.g. you can call \f(CW\*(C`ev_loop\*(C'\fR on the same loop from two |
3950 | different coroutines, and switch freely between both coroutines running the |
4238 | different coroutines, and switch freely between both coroutines running |
3951 | loop, as long as you don't confuse yourself). The only exception is that |
4239 | the loop, as long as you don't confuse yourself). The only exception is |
3952 | you must not do this from \f(CW\*(C`ev_periodic\*(C'\fR reschedule callbacks. |
4240 | that you must not do this from \f(CW\*(C`ev_periodic\*(C'\fR reschedule callbacks. |
3953 | .PP |
4241 | .PP |
3954 | Care has been taken to ensure that libev does not keep local state inside |
4242 | Care has been taken to ensure that libev does not keep local state inside |
3955 | \&\f(CW\*(C`ev_loop\*(C'\fR, and other calls do not usually allow for coroutine switches as |
4243 | \&\f(CW\*(C`ev_loop\*(C'\fR, and other calls do not usually allow for coroutine switches as |
3956 | they do not call any callbacks. |
4244 | they do not call any callbacks. |
3957 | .Sh "\s-1COMPILER\s0 \s-1WARNINGS\s0" |
4245 | .SS "\s-1COMPILER\s0 \s-1WARNINGS\s0" |
3958 | .IX Subsection "COMPILER WARNINGS" |
4246 | .IX Subsection "COMPILER WARNINGS" |
3959 | Depending on your compiler and compiler settings, you might get no or a |
4247 | Depending on your compiler and compiler settings, you might get no or a |
3960 | lot of warnings when compiling libev code. Some people are apparently |
4248 | lot of warnings when compiling libev code. Some people are apparently |
3961 | scared by this. |
4249 | scared by this. |
3962 | .PP |
4250 | .PP |
… | |
… | |
3979 | While libev is written to generate as few warnings as possible, |
4267 | While libev is written to generate as few warnings as possible, |
3980 | \&\*(L"warn-free\*(R" code is not a goal, and it is recommended not to build libev |
4268 | \&\*(L"warn-free\*(R" code is not a goal, and it is recommended not to build libev |
3981 | with any compiler warnings enabled unless you are prepared to cope with |
4269 | with any compiler warnings enabled unless you are prepared to cope with |
3982 | them (e.g. by ignoring them). Remember that warnings are just that: |
4270 | them (e.g. by ignoring them). Remember that warnings are just that: |
3983 | warnings, not errors, or proof of bugs. |
4271 | warnings, not errors, or proof of bugs. |
3984 | .Sh "\s-1VALGRIND\s0" |
4272 | .SS "\s-1VALGRIND\s0" |
3985 | .IX Subsection "VALGRIND" |
4273 | .IX Subsection "VALGRIND" |
3986 | Valgrind has a special section here because it is a popular tool that is |
4274 | Valgrind has a special section here because it is a popular tool that is |
3987 | highly useful. Unfortunately, valgrind reports are very hard to interpret. |
4275 | highly useful. Unfortunately, valgrind reports are very hard to interpret. |
3988 | .PP |
4276 | .PP |
3989 | If you think you found a bug (memory leak, uninitialised data access etc.) |
4277 | If you think you found a bug (memory leak, uninitialised data access etc.) |
… | |
… | |
4014 | .PP |
4302 | .PP |
4015 | If you need, for some reason, empty reports from valgrind for your project |
4303 | If you need, for some reason, empty reports from valgrind for your project |
4016 | I suggest using suppression lists. |
4304 | I suggest using suppression lists. |
4017 | .SH "PORTABILITY NOTES" |
4305 | .SH "PORTABILITY NOTES" |
4018 | .IX Header "PORTABILITY NOTES" |
4306 | .IX Header "PORTABILITY NOTES" |
4019 | .Sh "\s-1WIN32\s0 \s-1PLATFORM\s0 \s-1LIMITATIONS\s0 \s-1AND\s0 \s-1WORKAROUNDS\s0" |
4307 | .SS "\s-1WIN32\s0 \s-1PLATFORM\s0 \s-1LIMITATIONS\s0 \s-1AND\s0 \s-1WORKAROUNDS\s0" |
4020 | .IX Subsection "WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS" |
4308 | .IX Subsection "WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS" |
4021 | Win32 doesn't support any of the standards (e.g. \s-1POSIX\s0) that libev |
4309 | Win32 doesn't support any of the standards (e.g. \s-1POSIX\s0) that libev |
4022 | requires, and its I/O model is fundamentally incompatible with the \s-1POSIX\s0 |
4310 | requires, and its I/O model is fundamentally incompatible with the \s-1POSIX\s0 |
4023 | model. Libev still offers limited functionality on this platform in |
4311 | model. Libev still offers limited functionality on this platform in |
4024 | the form of the \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR backend, and only supports socket |
4312 | the form of the \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR backend, and only supports socket |
… | |
… | |
4111 | (another arbitrary limit), but is broken in many versions of the Microsoft |
4399 | (another arbitrary limit), but is broken in many versions of the Microsoft |
4112 | runtime libraries. This might get you to about \f(CW512\fR or \f(CW2048\fR sockets |
4400 | runtime libraries. This might get you to about \f(CW512\fR or \f(CW2048\fR sockets |
4113 | (depending on windows version and/or the phase of the moon). To get more, |
4401 | (depending on windows version and/or the phase of the moon). To get more, |
4114 | you need to wrap all I/O functions and provide your own fd management, but |
4402 | you need to wrap all I/O functions and provide your own fd management, but |
4115 | the cost of calling select (O(nA\*^X)) will likely make this unworkable. |
4403 | the cost of calling select (O(nA\*^X)) will likely make this unworkable. |
4116 | .Sh "\s-1PORTABILITY\s0 \s-1REQUIREMENTS\s0" |
4404 | .SS "\s-1PORTABILITY\s0 \s-1REQUIREMENTS\s0" |
4117 | .IX Subsection "PORTABILITY REQUIREMENTS" |
4405 | .IX Subsection "PORTABILITY REQUIREMENTS" |
4118 | In addition to a working ISO-C implementation and of course the |
4406 | In addition to a working ISO-C implementation and of course the |
4119 | backend-specific APIs, libev relies on a few additional extensions: |
4407 | backend-specific APIs, libev relies on a few additional extensions: |
4120 | .ie n .IP """void (*)(ev_watcher_type *, int revents)""\fR must have compatible calling conventions regardless of \f(CW""ev_watcher_type *""." 4 |
4408 | .ie n .IP """void (*)(ev_watcher_type *, int revents)"" must have compatible calling conventions regardless of ""ev_watcher_type *""." 4 |
4121 | .el .IP "\f(CWvoid (*)(ev_watcher_type *, int revents)\fR must have compatible calling conventions regardless of \f(CWev_watcher_type *\fR." 4 |
4409 | .el .IP "\f(CWvoid (*)(ev_watcher_type *, int revents)\fR must have compatible calling conventions regardless of \f(CWev_watcher_type *\fR." 4 |
4122 | .IX Item "void (*)(ev_watcher_type *, int revents) must have compatible calling conventions regardless of ev_watcher_type *." |
4410 | .IX Item "void (*)(ev_watcher_type *, int revents) must have compatible calling conventions regardless of ev_watcher_type *." |
4123 | Libev assumes not only that all watcher pointers have the same internal |
4411 | Libev assumes not only that all watcher pointers have the same internal |
4124 | structure (guaranteed by \s-1POSIX\s0 but not by \s-1ISO\s0 C for example), but it also |
4412 | structure (guaranteed by \s-1POSIX\s0 but not by \s-1ISO\s0 C for example), but it also |
4125 | assumes that the same (machine) code can be used to call any watcher |
4413 | assumes that the same (machine) code can be used to call any watcher |
… | |
… | |
4157 | .el .IP "\f(CWdouble\fR must hold a time value in seconds with enough accuracy" 4 |
4445 | .el .IP "\f(CWdouble\fR must hold a time value in seconds with enough accuracy" 4 |
4158 | .IX Item "double must hold a time value in seconds with enough accuracy" |
4446 | .IX Item "double must hold a time value in seconds with enough accuracy" |
4159 | The type \f(CW\*(C`double\*(C'\fR is used to represent timestamps. It is required to |
4447 | The type \f(CW\*(C`double\*(C'\fR is used to represent timestamps. It is required to |
4160 | have at least 51 bits of mantissa (and 9 bits of exponent), which is good |
4448 | have at least 51 bits of mantissa (and 9 bits of exponent), which is good |
4161 | enough for at least into the year 4000. This requirement is fulfilled by |
4449 | enough for at least into the year 4000. This requirement is fulfilled by |
4162 | implementations implementing \s-1IEEE\s0 754 (basically all existing ones). |
4450 | implementations implementing \s-1IEEE\s0 754, which is basically all existing |
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4451 | ones. With \s-1IEEE\s0 754 doubles, you get microsecond accuracy until at least |
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4452 | 2200. |
4163 | .PP |
4453 | .PP |
4164 | If you know of other additional requirements drop me a note. |
4454 | If you know of other additional requirements drop me a note. |
4165 | .SH "ALGORITHMIC COMPLEXITIES" |
4455 | .SH "ALGORITHMIC COMPLEXITIES" |
4166 | .IX Header "ALGORITHMIC COMPLEXITIES" |
4456 | .IX Header "ALGORITHMIC COMPLEXITIES" |
4167 | In this section the complexities of (many of) the algorithms used inside |
4457 | In this section the complexities of (many of) the algorithms used inside |