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Comparing libev/ev.3 (file contents):
Revision 1.31 by root, Wed Nov 28 11:31:34 2007 UTC vs.
Revision 1.34 by root, Thu Nov 29 12:21:21 2007 UTC

… …
127.\} 127.\}
128.rm #[ #] #H #V #F C 128.rm #[ #] #H #V #F C
129.\" ======================================================================== 129.\" ========================================================================
130.\" 130.\"
131.IX Title ""<STANDARD INPUT>" 1" 131.IX Title ""<STANDARD INPUT>" 1"
132.TH "<STANDARD INPUT>" 1 "2007-11-28" "perl v5.8.8" "User Contributed Perl Documentation" 132.TH "<STANDARD INPUT>" 1 "2007-11-29" "perl v5.8.8" "User Contributed Perl Documentation"
133.SH "NAME" 133.SH "NAME"
134libev \- a high performance full\-featured event loop written in C 134libev \- a high performance full\-featured event loop written in C
135.SH "SYNOPSIS" 135.SH "SYNOPSIS"
136.IX Header "SYNOPSIS" 136.IX Header "SYNOPSIS"
137.Vb 1 137.Vb 1
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305might be supported on the current system, you would need to look at 305might be supported on the current system, you would need to look at
306\&\f(CW\*(C`ev_embeddable_backends () & ev_supported_backends ()\*(C'\fR, likewise for 306\&\f(CW\*(C`ev_embeddable_backends () & ev_supported_backends ()\*(C'\fR, likewise for
307recommended ones. 307recommended ones.
308.Sp 308.Sp
309See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. 309See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info.
310.IP "ev_set_allocator (void *(*cb)(void *ptr, size_t size))" 4 310.IP "ev_set_allocator (void *(*cb)(void *ptr, long size))" 4
311.IX Item "ev_set_allocator (void *(*cb)(void *ptr, size_t size))" 311.IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))"
312Sets the allocation function to use (the prototype and semantics are 312Sets the allocation function to use (the prototype is similar \- the
313identical to the realloc C function). It is used to allocate and free 313semantics is identical \- to the realloc C function). It is used to
314memory (no surprises here). If it returns zero when memory needs to be 314allocate and free memory (no surprises here). If it returns zero when
315allocated, the library might abort or take some potentially destructive 315memory needs to be allocated, the library might abort or take some
316action. The default is your system realloc function. 316potentially destructive action. The default is your system realloc
317function.
317.Sp 318.Sp
318You could override this function in high-availability programs to, say, 319You could override this function in high-availability programs to, say,
319free some memory if it cannot allocate memory, to use a special allocator, 320free some memory if it cannot allocate memory, to use a special allocator,
320or even to sleep a while and retry until some memory is available. 321or even to sleep a while and retry until some memory is available.
321.Sp 322.Sp
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1070.IP "ev_timer_again (loop)" 4 1071.IP "ev_timer_again (loop)" 4
1071.IX Item "ev_timer_again (loop)" 1072.IX Item "ev_timer_again (loop)"
1072This will act as if the timer timed out and restart it again if it is 1073This will act as if the timer timed out and restart it again if it is
1073repeating. The exact semantics are: 1074repeating. The exact semantics are:
1074.Sp 1075.Sp
1076If the timer is pending, its pending status is cleared.
1077.Sp
1075If the timer is started but nonrepeating, stop it. 1078If the timer is started but nonrepeating, stop it (as if it timed out).
1076.Sp 1079.Sp
1077If the timer is repeating, either start it if necessary (with the repeat 1080If the timer is repeating, either start it if necessary (with the
1078value), or reset the running timer to the repeat value. 1081\&\f(CW\*(C`repeat\*(C'\fR value), or reset the running timer to the \f(CW\*(C`repeat\*(C'\fR value.
1079.Sp 1082.Sp
1080This sounds a bit complicated, but here is a useful and typical 1083This sounds a bit complicated, but here is a useful and typical
1081example: Imagine you have a tcp connection and you want a so-called 1084example: Imagine you have a tcp connection and you want a so-called idle
1082idle timeout, that is, you want to be called when there have been, 1085timeout, that is, you want to be called when there have been, say, 60
1083say, 60 seconds of inactivity on the socket. The easiest way to do 1086seconds of inactivity on the socket. The easiest way to do this is to
1084this is to configure an \f(CW\*(C`ev_timer\*(C'\fR with \f(CW\*(C`after\*(C'\fR=\f(CW\*(C`repeat\*(C'\fR=\f(CW60\fR and calling 1087configure an \f(CW\*(C`ev_timer\*(C'\fR with a \f(CW\*(C`repeat\*(C'\fR value of \f(CW60\fR and then call
1085\&\f(CW\*(C`ev_timer_again\*(C'\fR each time you successfully read or write some data. If 1088\&\f(CW\*(C`ev_timer_again\*(C'\fR each time you successfully read or write some data. If
1086you go into an idle state where you do not expect data to travel on the 1089you go into an idle state where you do not expect data to travel on the
1087socket, you can stop the timer, and again will automatically restart it if 1090socket, you can \f(CW\*(C`ev_timer_stop\*(C'\fR the timer, and \f(CW\*(C`ev_timer_again\*(C'\fR will
1088need be. 1091automatically restart it if need be.
1089.Sp 1092.Sp
1090You can also ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR altogether 1093That means you can ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR
1091and only ever use the \f(CW\*(C`repeat\*(C'\fR value: 1094altogether and only ever use the \f(CW\*(C`repeat\*(C'\fR value and \f(CW\*(C`ev_timer_again\*(C'\fR:
1092.Sp 1095.Sp
1093.Vb 8 1096.Vb 8
1094\& ev_timer_init (timer, callback, 0., 5.); 1097\& ev_timer_init (timer, callback, 0., 5.);
1095\& ev_timer_again (loop, timer); 1098\& ev_timer_again (loop, timer);
1096\& ... 1099\& ...
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1099\& ... 1102\& ...
1100\& timer->again = 10.; 1103\& timer->again = 10.;
1101\& ev_timer_again (loop, timer); 1104\& ev_timer_again (loop, timer);
1102.Ve 1105.Ve
1103.Sp 1106.Sp
1104This is more efficient then stopping/starting the timer eahc time you want 1107This is more slightly efficient then stopping/starting the timer each time
1105to modify its timeout value. 1108you want to modify its timeout value.
1106.IP "ev_tstamp repeat [read\-write]" 4 1109.IP "ev_tstamp repeat [read\-write]" 4
1107.IX Item "ev_tstamp repeat [read-write]" 1110.IX Item "ev_tstamp repeat [read-write]"
1108The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out 1111The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out
1109or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any), 1112or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any),
1110which is also when any modifications are taken into account. 1113which is also when any modifications are taken into account.
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1382The path does not need to exist: changing from \*(L"path exists\*(R" to \*(L"path does 1385The path does not need to exist: changing from \*(L"path exists\*(R" to \*(L"path does
1383not exist\*(R" is a status change like any other. The condition \*(L"path does 1386not exist\*(R" is a status change like any other. The condition \*(L"path does
1384not exist\*(R" is signified by the \f(CW\*(C`st_nlink\*(C'\fR field being zero (which is 1387not exist\*(R" is signified by the \f(CW\*(C`st_nlink\*(C'\fR field being zero (which is
1385otherwise always forced to be at least one) and all the other fields of 1388otherwise always forced to be at least one) and all the other fields of
1386the stat buffer having unspecified contents. 1389the stat buffer having unspecified contents.
1390.PP
1391The path \fIshould\fR be absolute and \fImust not\fR end in a slash. If it is
1392relative and your working directory changes, the behaviour is undefined.
1387.PP 1393.PP
1388Since there is no standard to do this, the portable implementation simply 1394Since there is no standard to do this, the portable implementation simply
1389calls \f(CW\*(C`stat (2)\*(C'\fR regularly on the path to see if it changed somehow. You 1395calls \f(CW\*(C`stat (2)\*(C'\fR regularly on the path to see if it changed somehow. You
1390can specify a recommended polling interval for this case. If you specify 1396can specify a recommended polling interval for this case. If you specify
1391a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable, 1397a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable,

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