… | |
… | |
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 "2007-11-24" "perl v5.8.8" "User Contributed Perl Documentation" |
132 | .TH "<STANDARD INPUT>" 1 "2007-11-27" "perl v5.8.8" "User Contributed Perl Documentation" |
133 | .SH "NAME" |
133 | .SH "NAME" |
134 | libev \- a high performance full\-featured event loop written in C |
134 | libev \- 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 |
… | |
… | |
240 | might be supported on the current system, you would need to look at |
240 | might be supported on the current system, you would need to look at |
241 | \&\f(CW\*(C`ev_embeddable_backends () & ev_supported_backends ()\*(C'\fR, likewise for |
241 | \&\f(CW\*(C`ev_embeddable_backends () & ev_supported_backends ()\*(C'\fR, likewise for |
242 | recommended ones. |
242 | recommended ones. |
243 | .Sp |
243 | .Sp |
244 | See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
244 | See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info. |
245 | .IP "ev_set_allocator (void *(*cb)(void *ptr, long size))" 4 |
245 | .IP "ev_set_allocator (void *(*cb)(void *ptr, size_t size))" 4 |
246 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size))" |
246 | .IX Item "ev_set_allocator (void *(*cb)(void *ptr, size_t size))" |
247 | Sets the allocation function to use (the prototype is similar to the |
247 | Sets the allocation function to use (the prototype and semantics are |
248 | realloc C function, the semantics are identical). It is used to allocate |
248 | identical to the realloc C function). It is used to allocate and free |
249 | and free memory (no surprises here). If it returns zero when memory |
249 | memory (no surprises here). If it returns zero when memory needs to be |
250 | needs to be allocated, the library might abort or take some potentially |
250 | allocated, the library might abort or take some potentially destructive |
251 | destructive action. The default is your system realloc function. |
251 | action. The default is your system realloc function. |
252 | .Sp |
252 | .Sp |
253 | You could override this function in high-availability programs to, say, |
253 | You could override this function in high-availability programs to, say, |
254 | free some memory if it cannot allocate memory, to use a special allocator, |
254 | free some memory if it cannot allocate memory, to use a special allocator, |
255 | or even to sleep a while and retry until some memory is available. |
255 | or even to sleep a while and retry until some memory is available. |
256 | .Sp |
256 | .Sp |
257 | Example: replace the libev allocator with one that waits a bit and then |
257 | Example: replace the libev allocator with one that waits a bit and then |
258 | retries: better than mine). |
258 | retries: better than mine). |
259 | .Sp |
259 | .Sp |
260 | .Vb 6 |
260 | .Vb 6 |
261 | \& static void * |
261 | \& static void * |
262 | \& persistent_realloc (void *ptr, long size) |
262 | \& persistent_realloc (void *ptr, size_t size) |
263 | \& { |
263 | \& { |
264 | \& for (;;) |
264 | \& for (;;) |
265 | \& { |
265 | \& { |
266 | \& void *newptr = realloc (ptr, size); |
266 | \& void *newptr = realloc (ptr, size); |
267 | .Ve |
267 | .Ve |
… | |
… | |
458 | \& fatal ("no epoll found here, maybe it hides under your chair"); |
458 | \& fatal ("no epoll found here, maybe it hides under your chair"); |
459 | .Ve |
459 | .Ve |
460 | .IP "ev_default_destroy ()" 4 |
460 | .IP "ev_default_destroy ()" 4 |
461 | .IX Item "ev_default_destroy ()" |
461 | .IX Item "ev_default_destroy ()" |
462 | Destroys the default loop again (frees all memory and kernel state |
462 | Destroys the default loop again (frees all memory and kernel state |
463 | etc.). This stops all registered event watchers (by not touching them in |
463 | etc.). None of the active event watchers will be stopped in the normal |
464 | any way whatsoever, although you cannot rely on this :). |
464 | sense, so e.g. \f(CW\*(C`ev_is_active\*(C'\fR might still return true. It is your |
|
|
465 | responsibility to either stop all watchers cleanly yoursef \fIbefore\fR |
|
|
466 | calling this function, or cope with the fact afterwards (which is usually |
|
|
467 | the easiest thing, youc na just ignore the watchers and/or \f(CW\*(C`free ()\*(C'\fR them |
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|
468 | for example). |
465 | .IP "ev_loop_destroy (loop)" 4 |
469 | .IP "ev_loop_destroy (loop)" 4 |
466 | .IX Item "ev_loop_destroy (loop)" |
470 | .IX Item "ev_loop_destroy (loop)" |
467 | Like \f(CW\*(C`ev_default_destroy\*(C'\fR, but destroys an event loop created by an |
471 | Like \f(CW\*(C`ev_default_destroy\*(C'\fR, but destroys an event loop created by an |
468 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
472 | earlier call to \f(CW\*(C`ev_loop_new\*(C'\fR. |
469 | .IP "ev_default_fork ()" 4 |
473 | .IP "ev_default_fork ()" 4 |
… | |
… | |
680 | The signal specified in the \f(CW\*(C`ev_signal\*(C'\fR watcher has been received by a thread. |
684 | The signal specified in the \f(CW\*(C`ev_signal\*(C'\fR watcher has been received by a thread. |
681 | .ie n .IP """EV_CHILD""" 4 |
685 | .ie n .IP """EV_CHILD""" 4 |
682 | .el .IP "\f(CWEV_CHILD\fR" 4 |
686 | .el .IP "\f(CWEV_CHILD\fR" 4 |
683 | .IX Item "EV_CHILD" |
687 | .IX Item "EV_CHILD" |
684 | The pid specified in the \f(CW\*(C`ev_child\*(C'\fR watcher has received a status change. |
688 | The pid specified in the \f(CW\*(C`ev_child\*(C'\fR watcher has received a status change. |
|
|
689 | .ie n .IP """EV_STAT""" 4 |
|
|
690 | .el .IP "\f(CWEV_STAT\fR" 4 |
|
|
691 | .IX Item "EV_STAT" |
|
|
692 | The path specified in the \f(CW\*(C`ev_stat\*(C'\fR watcher changed its attributes somehow. |
685 | .ie n .IP """EV_IDLE""" 4 |
693 | .ie n .IP """EV_IDLE""" 4 |
686 | .el .IP "\f(CWEV_IDLE\fR" 4 |
694 | .el .IP "\f(CWEV_IDLE\fR" 4 |
687 | .IX Item "EV_IDLE" |
695 | .IX Item "EV_IDLE" |
688 | The \f(CW\*(C`ev_idle\*(C'\fR watcher has determined that you have nothing better to do. |
696 | The \f(CW\*(C`ev_idle\*(C'\fR watcher has determined that you have nothing better to do. |
689 | .ie n .IP """EV_PREPARE""" 4 |
697 | .ie n .IP """EV_PREPARE""" 4 |
… | |
… | |
699 | \&\f(CW\*(C`ev_loop\*(C'\fR has gathered them, but before it invokes any callbacks for any |
707 | \&\f(CW\*(C`ev_loop\*(C'\fR has gathered them, but before it invokes any callbacks for any |
700 | received events. Callbacks of both watcher types can start and stop as |
708 | received events. Callbacks of both watcher types can start and stop as |
701 | many watchers as they want, and all of them will be taken into account |
709 | many watchers as they want, and all of them will be taken into account |
702 | (for example, a \f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep |
710 | (for example, a \f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep |
703 | \&\f(CW\*(C`ev_loop\*(C'\fR from blocking). |
711 | \&\f(CW\*(C`ev_loop\*(C'\fR from blocking). |
|
|
712 | .ie n .IP """EV_EMBED""" 4 |
|
|
713 | .el .IP "\f(CWEV_EMBED\fR" 4 |
|
|
714 | .IX Item "EV_EMBED" |
|
|
715 | The embedded event loop specified in the \f(CW\*(C`ev_embed\*(C'\fR watcher needs attention. |
|
|
716 | .ie n .IP """EV_FORK""" 4 |
|
|
717 | .el .IP "\f(CWEV_FORK\fR" 4 |
|
|
718 | .IX Item "EV_FORK" |
|
|
719 | The event loop has been resumed in the child process after fork (see |
|
|
720 | \&\f(CW\*(C`ev_fork\*(C'\fR). |
704 | .ie n .IP """EV_ERROR""" 4 |
721 | .ie n .IP """EV_ERROR""" 4 |
705 | .el .IP "\f(CWEV_ERROR\fR" 4 |
722 | .el .IP "\f(CWEV_ERROR\fR" 4 |
706 | .IX Item "EV_ERROR" |
723 | .IX Item "EV_ERROR" |
707 | An unspecified error has occured, the watcher has been stopped. This might |
724 | An unspecified error has occured, the watcher has been stopped. This might |
708 | happen because the watcher could not be properly started because libev |
725 | happen because the watcher could not be properly started because libev |
… | |
… | |
713 | Libev will usually signal a few \*(L"dummy\*(R" events together with an error, |
730 | Libev will usually signal a few \*(L"dummy\*(R" events together with an error, |
714 | for example it might indicate that a fd is readable or writable, and if |
731 | for example it might indicate that a fd is readable or writable, and if |
715 | your callbacks is well-written it can just attempt the operation and cope |
732 | your callbacks is well-written it can just attempt the operation and cope |
716 | with the error from \fIread()\fR or \fIwrite()\fR. This will not work in multithreaded |
733 | with the error from \fIread()\fR or \fIwrite()\fR. This will not work in multithreaded |
717 | programs, though, so beware. |
734 | programs, though, so beware. |
718 | .Sh "\s-1SUMMARY\s0 \s-1OF\s0 \s-1GENERIC\s0 \s-1WATCHER\s0 \s-1FUNCTIONS\s0" |
735 | .Sh "\s-1GENERIC\s0 \s-1WATCHER\s0 \s-1FUNCTIONS\s0" |
719 | .IX Subsection "SUMMARY OF GENERIC WATCHER FUNCTIONS" |
736 | .IX Subsection "GENERIC WATCHER FUNCTIONS" |
720 | In the following description, \f(CW\*(C`TYPE\*(C'\fR stands for the watcher type, |
737 | In the following description, \f(CW\*(C`TYPE\*(C'\fR stands for the watcher type, |
721 | e.g. \f(CW\*(C`timer\*(C'\fR for \f(CW\*(C`ev_timer\*(C'\fR watchers and \f(CW\*(C`io\*(C'\fR for \f(CW\*(C`ev_io\*(C'\fR watchers. |
738 | e.g. \f(CW\*(C`timer\*(C'\fR for \f(CW\*(C`ev_timer\*(C'\fR watchers and \f(CW\*(C`io\*(C'\fR for \f(CW\*(C`ev_io\*(C'\fR watchers. |
722 | .ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4 |
739 | .ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4 |
723 | .el .IP "\f(CWev_init\fR (ev_TYPE *watcher, callback)" 4 |
740 | .el .IP "\f(CWev_init\fR (ev_TYPE *watcher, callback)" 4 |
724 | .IX Item "ev_init (ev_TYPE *watcher, callback)" |
741 | .IX Item "ev_init (ev_TYPE *watcher, callback)" |
… | |
… | |
730 | which rolls both calls into one. |
747 | which rolls both calls into one. |
731 | .Sp |
748 | .Sp |
732 | You can reinitialise a watcher at any time as long as it has been stopped |
749 | You can reinitialise a watcher at any time as long as it has been stopped |
733 | (or never started) and there are no pending events outstanding. |
750 | (or never started) and there are no pending events outstanding. |
734 | .Sp |
751 | .Sp |
735 | The callbakc is always of type \f(CW\*(C`void (*)(ev_loop *loop, ev_TYPE *watcher, |
752 | The callback is always of type \f(CW\*(C`void (*)(ev_loop *loop, ev_TYPE *watcher, |
736 | int revents)\*(C'\fR. |
753 | int revents)\*(C'\fR. |
737 | .ie n .IP """ev_TYPE_set"" (ev_TYPE *, [args])" 4 |
754 | .ie n .IP """ev_TYPE_set"" (ev_TYPE *, [args])" 4 |
738 | .el .IP "\f(CWev_TYPE_set\fR (ev_TYPE *, [args])" 4 |
755 | .el .IP "\f(CWev_TYPE_set\fR (ev_TYPE *, [args])" 4 |
739 | .IX Item "ev_TYPE_set (ev_TYPE *, [args])" |
756 | .IX Item "ev_TYPE_set (ev_TYPE *, [args])" |
740 | This macro initialises the type-specific parts of a watcher. You need to |
757 | This macro initialises the type-specific parts of a watcher. You need to |
… | |
… | |
817 | More interesting and less C\-conformant ways of catsing your callback type |
834 | More interesting and less C\-conformant ways of catsing your callback type |
818 | have been omitted.... |
835 | have been omitted.... |
819 | .SH "WATCHER TYPES" |
836 | .SH "WATCHER TYPES" |
820 | .IX Header "WATCHER TYPES" |
837 | .IX Header "WATCHER TYPES" |
821 | This section describes each watcher in detail, but will not repeat |
838 | This section describes each watcher in detail, but will not repeat |
822 | information given in the last section. |
839 | information given in the last section. Any initialisation/set macros, |
|
|
840 | functions and members specific to the watcher type are explained. |
|
|
841 | .PP |
|
|
842 | Members are additionally marked with either \fI[read\-only]\fR, meaning that, |
|
|
843 | while the watcher is active, you can look at the member and expect some |
|
|
844 | sensible content, but you must not modify it (you can modify it while the |
|
|
845 | watcher is stopped to your hearts content), or \fI[read\-write]\fR, which |
|
|
846 | means you can expect it to have some sensible content while the watcher |
|
|
847 | is active, but you can also modify it. Modifying it may not do something |
|
|
848 | sensible or take immediate effect (or do anything at all), but libev will |
|
|
849 | not crash or malfunction in any way. |
823 | .ie n .Sh """ev_io"" \- is this file descriptor readable or writable" |
850 | .ie n .Sh """ev_io"" \- is this file descriptor readable or writable?" |
824 | .el .Sh "\f(CWev_io\fP \- is this file descriptor readable or writable" |
851 | .el .Sh "\f(CWev_io\fP \- is this file descriptor readable or writable?" |
825 | .IX Subsection "ev_io - is this file descriptor readable or writable" |
852 | .IX Subsection "ev_io - is this file descriptor readable or writable?" |
826 | I/O watchers check whether a file descriptor is readable or writable |
853 | I/O watchers check whether a file descriptor is readable or writable |
827 | in each iteration of the event loop (This behaviour is called |
854 | in each iteration of the event loop, or, more precisely, when reading |
828 | level-triggering because you keep receiving events as long as the |
855 | would not block the process and writing would at least be able to write |
829 | condition persists. Remember you can stop the watcher if you don't want to |
856 | some data. This behaviour is called level-triggering because you keep |
830 | act on the event and neither want to receive future events). |
857 | receiving events as long as the condition persists. Remember you can stop |
|
|
858 | the watcher if you don't want to act on the event and neither want to |
|
|
859 | receive future events. |
831 | .PP |
860 | .PP |
832 | In general you can register as many read and/or write event watchers per |
861 | In general you can register as many read and/or write event watchers per |
833 | fd as you want (as long as you don't confuse yourself). Setting all file |
862 | fd as you want (as long as you don't confuse yourself). Setting all file |
834 | descriptors to non-blocking mode is also usually a good idea (but not |
863 | descriptors to non-blocking mode is also usually a good idea (but not |
835 | required if you know what you are doing). |
864 | required if you know what you are doing). |
836 | .PP |
865 | .PP |
837 | You have to be careful with dup'ed file descriptors, though. Some backends |
866 | You have to be careful with dup'ed file descriptors, though. Some backends |
838 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
867 | (the linux epoll backend is a notable example) cannot handle dup'ed file |
839 | descriptors correctly if you register interest in two or more fds pointing |
868 | descriptors correctly if you register interest in two or more fds pointing |
840 | to the same underlying file/socket etc. description (that is, they share |
869 | to the same underlying file/socket/etc. description (that is, they share |
841 | the same underlying \*(L"file open\*(R"). |
870 | the same underlying \*(L"file open\*(R"). |
842 | .PP |
871 | .PP |
843 | If you must do this, then force the use of a known-to-be-good backend |
872 | If you must do this, then force the use of a known-to-be-good backend |
844 | (at the time of this writing, this includes only \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR and |
873 | (at the time of this writing, this includes only \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR and |
845 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR). |
874 | \&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR). |
|
|
875 | .PP |
|
|
876 | Another thing you have to watch out for is that it is quite easy to |
|
|
877 | receive \*(L"spurious\*(R" readyness notifications, that is your callback might |
|
|
878 | be called with \f(CW\*(C`EV_READ\*(C'\fR but a subsequent \f(CW\*(C`read\*(C'\fR(2) will actually block |
|
|
879 | because there is no data. Not only are some backends known to create a |
|
|
880 | lot of those (for example solaris ports), it is very easy to get into |
|
|
881 | this situation even with a relatively standard program structure. Thus |
|
|
882 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
|
|
883 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
|
|
884 | .PP |
|
|
885 | If you cannot run the fd in non-blocking mode (for example you should not |
|
|
886 | play around with an Xlib connection), then you have to seperately re-test |
|
|
887 | wether a file descriptor is really ready with a known-to-be good interface |
|
|
888 | such as poll (fortunately in our Xlib example, Xlib already does this on |
|
|
889 | its own, so its quite safe to use). |
846 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
890 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
847 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
891 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
848 | .PD 0 |
892 | .PD 0 |
849 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
893 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
850 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
894 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
851 | .PD |
895 | .PD |
852 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The fd is the file descriptor to rceeive |
896 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The \f(CW\*(C`fd\*(C'\fR is the file descriptor to |
853 | events for and events is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or \f(CW\*(C`EV_READ | |
897 | rceeive events for and events is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or |
854 | EV_WRITE\*(C'\fR to receive the given events. |
898 | \&\f(CW\*(C`EV_READ | EV_WRITE\*(C'\fR to receive the given events. |
855 | .Sp |
899 | .IP "int fd [read\-only]" 4 |
856 | Please note that most of the more scalable backend mechanisms (for example |
900 | .IX Item "int fd [read-only]" |
857 | epoll and solaris ports) can result in spurious readyness notifications |
901 | The file descriptor being watched. |
858 | for file descriptors, so you practically need to use non-blocking I/O (and |
902 | .IP "int events [read\-only]" 4 |
859 | treat callback invocation as hint only), or retest separately with a safe |
903 | .IX Item "int events [read-only]" |
860 | interface before doing I/O (XLib can do this), or force the use of either |
904 | The events being watched. |
861 | \&\f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR, which don't suffer from this |
|
|
862 | problem. Also note that it is quite easy to have your callback invoked |
|
|
863 | when the readyness condition is no longer valid even when employing |
|
|
864 | typical ways of handling events, so its a good idea to use non-blocking |
|
|
865 | I/O unconditionally. |
|
|
866 | .PP |
905 | .PP |
867 | Example: call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
906 | Example: call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
868 | readable, but only once. Since it is likely line\-buffered, you could |
907 | readable, but only once. Since it is likely line\-buffered, you could |
869 | attempt to read a whole line in the callback: |
908 | attempt to read a whole line in the callback: |
870 | .PP |
909 | .PP |
… | |
… | |
883 | \& struct ev_io stdin_readable; |
922 | \& struct ev_io stdin_readable; |
884 | \& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
923 | \& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ); |
885 | \& ev_io_start (loop, &stdin_readable); |
924 | \& ev_io_start (loop, &stdin_readable); |
886 | \& ev_loop (loop, 0); |
925 | \& ev_loop (loop, 0); |
887 | .Ve |
926 | .Ve |
888 | .ie n .Sh """ev_timer"" \- relative and optionally recurring timeouts" |
927 | .ie n .Sh """ev_timer"" \- relative and optionally repeating timeouts" |
889 | .el .Sh "\f(CWev_timer\fP \- relative and optionally recurring timeouts" |
928 | .el .Sh "\f(CWev_timer\fP \- relative and optionally repeating timeouts" |
890 | .IX Subsection "ev_timer - relative and optionally recurring timeouts" |
929 | .IX Subsection "ev_timer - relative and optionally repeating timeouts" |
891 | Timer watchers are simple relative timers that generate an event after a |
930 | Timer watchers are simple relative timers that generate an event after a |
892 | given time, and optionally repeating in regular intervals after that. |
931 | given time, and optionally repeating in regular intervals after that. |
893 | .PP |
932 | .PP |
894 | The timers are based on real time, that is, if you register an event that |
933 | The timers are based on real time, that is, if you register an event that |
895 | times out after an hour and you reset your system clock to last years |
934 | times out after an hour and you reset your system clock to last years |
… | |
… | |
935 | .Sp |
974 | .Sp |
936 | If the timer is repeating, either start it if necessary (with the repeat |
975 | If the timer is repeating, either start it if necessary (with the repeat |
937 | value), or reset the running timer to the repeat value. |
976 | value), or reset the running timer to the repeat value. |
938 | .Sp |
977 | .Sp |
939 | This sounds a bit complicated, but here is a useful and typical |
978 | This sounds a bit complicated, but here is a useful and typical |
940 | example: Imagine you have a tcp connection and you want a so-called idle |
979 | example: Imagine you have a tcp connection and you want a so-called |
941 | timeout, that is, you want to be called when there have been, say, 60 |
980 | idle timeout, that is, you want to be called when there have been, |
942 | seconds of inactivity on the socket. The easiest way to do this is to |
981 | say, 60 seconds of inactivity on the socket. The easiest way to do |
943 | configure an \f(CW\*(C`ev_timer\*(C'\fR with after=repeat=60 and calling ev_timer_again each |
982 | this 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 |
944 | time you successfully read or write some data. If you go into an idle |
983 | \&\f(CW\*(C`ev_timer_again\*(C'\fR each time you successfully read or write some data. If |
945 | state where you do not expect data to travel on the socket, you can stop |
984 | you go into an idle state where you do not expect data to travel on the |
946 | the timer, and again will automatically restart it if need be. |
985 | socket, you can stop the timer, and again will automatically restart it if |
|
|
986 | need be. |
|
|
987 | .Sp |
|
|
988 | You can also ignore the \f(CW\*(C`after\*(C'\fR value and \f(CW\*(C`ev_timer_start\*(C'\fR altogether |
|
|
989 | and only ever use the \f(CW\*(C`repeat\*(C'\fR value: |
|
|
990 | .Sp |
|
|
991 | .Vb 8 |
|
|
992 | \& ev_timer_init (timer, callback, 0., 5.); |
|
|
993 | \& ev_timer_again (loop, timer); |
|
|
994 | \& ... |
|
|
995 | \& timer->again = 17.; |
|
|
996 | \& ev_timer_again (loop, timer); |
|
|
997 | \& ... |
|
|
998 | \& timer->again = 10.; |
|
|
999 | \& ev_timer_again (loop, timer); |
|
|
1000 | .Ve |
|
|
1001 | .Sp |
|
|
1002 | This is more efficient then stopping/starting the timer eahc time you want |
|
|
1003 | to modify its timeout value. |
|
|
1004 | .IP "ev_tstamp repeat [read\-write]" 4 |
|
|
1005 | .IX Item "ev_tstamp repeat [read-write]" |
|
|
1006 | The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out |
|
|
1007 | or \f(CW\*(C`ev_timer_again\*(C'\fR is called and determines the next timeout (if any), |
|
|
1008 | which is also when any modifications are taken into account. |
947 | .PP |
1009 | .PP |
948 | Example: create a timer that fires after 60 seconds. |
1010 | Example: create a timer that fires after 60 seconds. |
949 | .PP |
1011 | .PP |
950 | .Vb 5 |
1012 | .Vb 5 |
951 | \& static void |
1013 | \& static void |
… | |
… | |
982 | .Vb 3 |
1044 | .Vb 3 |
983 | \& // and in some piece of code that gets executed on any "activity": |
1045 | \& // and in some piece of code that gets executed on any "activity": |
984 | \& // reset the timeout to start ticking again at 10 seconds |
1046 | \& // reset the timeout to start ticking again at 10 seconds |
985 | \& ev_timer_again (&mytimer); |
1047 | \& ev_timer_again (&mytimer); |
986 | .Ve |
1048 | .Ve |
987 | .ie n .Sh """ev_periodic"" \- to cron or not to cron" |
1049 | .ie n .Sh """ev_periodic"" \- to cron or not to cron?" |
988 | .el .Sh "\f(CWev_periodic\fP \- to cron or not to cron" |
1050 | .el .Sh "\f(CWev_periodic\fP \- to cron or not to cron?" |
989 | .IX Subsection "ev_periodic - to cron or not to cron" |
1051 | .IX Subsection "ev_periodic - to cron or not to cron?" |
990 | Periodic watchers are also timers of a kind, but they are very versatile |
1052 | Periodic watchers are also timers of a kind, but they are very versatile |
991 | (and unfortunately a bit complex). |
1053 | (and unfortunately a bit complex). |
992 | .PP |
1054 | .PP |
993 | Unlike \f(CW\*(C`ev_timer\*(C'\fR's, they are not based on real time (or relative time) |
1055 | Unlike \f(CW\*(C`ev_timer\*(C'\fR's, they are not based on real time (or relative time) |
994 | but on wallclock time (absolute time). You can tell a periodic watcher |
1056 | but on wallclock time (absolute time). You can tell a periodic watcher |
995 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
1057 | to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a |
996 | periodic watcher to trigger in 10 seconds (by specifiying e.g. c<ev_now () |
1058 | periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now () |
997 | + 10.>) and then reset your system clock to the last year, then it will |
1059 | + 10.\*(C'\fR) and then reset your system clock to the last year, then it will |
998 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
1060 | take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger |
999 | roughly 10 seconds later and of course not if you reset your system time |
1061 | roughly 10 seconds later and of course not if you reset your system time |
1000 | again). |
1062 | again). |
1001 | .PP |
1063 | .PP |
1002 | They can also be used to implement vastly more complex timers, such as |
1064 | They can also be used to implement vastly more complex timers, such as |
… | |
… | |
1083 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1145 | .IX Item "ev_periodic_again (loop, ev_periodic *)" |
1084 | Simply stops and restarts the periodic watcher again. This is only useful |
1146 | Simply stops and restarts the periodic watcher again. This is only useful |
1085 | when you changed some parameters or the reschedule callback would return |
1147 | when you changed some parameters or the reschedule callback would return |
1086 | a different time than the last time it was called (e.g. in a crond like |
1148 | a different time than the last time it was called (e.g. in a crond like |
1087 | program when the crontabs have changed). |
1149 | program when the crontabs have changed). |
|
|
1150 | .IP "ev_tstamp interval [read\-write]" 4 |
|
|
1151 | .IX Item "ev_tstamp interval [read-write]" |
|
|
1152 | The current interval value. Can be modified any time, but changes only |
|
|
1153 | take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being |
|
|
1154 | called. |
|
|
1155 | .IP "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read\-write]" 4 |
|
|
1156 | .IX Item "ev_tstamp (*reschedule_cb)(struct ev_periodic *w, ev_tstamp now) [read-write]" |
|
|
1157 | The current reschedule callback, or \f(CW0\fR, if this functionality is |
|
|
1158 | switched off. Can be changed any time, but changes only take effect when |
|
|
1159 | the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called. |
1088 | .PP |
1160 | .PP |
1089 | Example: call a callback every hour, or, more precisely, whenever the |
1161 | Example: call a callback every hour, or, more precisely, whenever the |
1090 | system clock is divisible by 3600. The callback invocation times have |
1162 | system clock is divisible by 3600. The callback invocation times have |
1091 | potentially a lot of jittering, but good long-term stability. |
1163 | potentially a lot of jittering, but good long-term stability. |
1092 | .PP |
1164 | .PP |
… | |
… | |
1128 | \& struct ev_periodic hourly_tick; |
1200 | \& struct ev_periodic hourly_tick; |
1129 | \& ev_periodic_init (&hourly_tick, clock_cb, |
1201 | \& ev_periodic_init (&hourly_tick, clock_cb, |
1130 | \& fmod (ev_now (loop), 3600.), 3600., 0); |
1202 | \& fmod (ev_now (loop), 3600.), 3600., 0); |
1131 | \& ev_periodic_start (loop, &hourly_tick); |
1203 | \& ev_periodic_start (loop, &hourly_tick); |
1132 | .Ve |
1204 | .Ve |
1133 | .ie n .Sh """ev_signal"" \- signal me when a signal gets signalled" |
1205 | .ie n .Sh """ev_signal"" \- signal me when a signal gets signalled!" |
1134 | .el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled" |
1206 | .el .Sh "\f(CWev_signal\fP \- signal me when a signal gets signalled!" |
1135 | .IX Subsection "ev_signal - signal me when a signal gets signalled" |
1207 | .IX Subsection "ev_signal - signal me when a signal gets signalled!" |
1136 | Signal watchers will trigger an event when the process receives a specific |
1208 | Signal watchers will trigger an event when the process receives a specific |
1137 | signal one or more times. Even though signals are very asynchronous, libev |
1209 | signal one or more times. Even though signals are very asynchronous, libev |
1138 | will try it's best to deliver signals synchronously, i.e. as part of the |
1210 | will try it's best to deliver signals synchronously, i.e. as part of the |
1139 | normal event processing, like any other event. |
1211 | normal event processing, like any other event. |
1140 | .PP |
1212 | .PP |
… | |
… | |
1150 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1222 | .IP "ev_signal_set (ev_signal *, int signum)" 4 |
1151 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
1223 | .IX Item "ev_signal_set (ev_signal *, int signum)" |
1152 | .PD |
1224 | .PD |
1153 | Configures the watcher to trigger on the given signal number (usually one |
1225 | Configures the watcher to trigger on the given signal number (usually one |
1154 | of the \f(CW\*(C`SIGxxx\*(C'\fR constants). |
1226 | of the \f(CW\*(C`SIGxxx\*(C'\fR constants). |
|
|
1227 | .IP "int signum [read\-only]" 4 |
|
|
1228 | .IX Item "int signum [read-only]" |
|
|
1229 | The signal the watcher watches out for. |
1155 | .ie n .Sh """ev_child"" \- wait for pid status changes" |
1230 | .ie n .Sh """ev_child"" \- watch out for process status changes" |
1156 | .el .Sh "\f(CWev_child\fP \- wait for pid status changes" |
1231 | .el .Sh "\f(CWev_child\fP \- watch out for process status changes" |
1157 | .IX Subsection "ev_child - wait for pid status changes" |
1232 | .IX Subsection "ev_child - watch out for process status changes" |
1158 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1233 | Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to |
1159 | some child status changes (most typically when a child of yours dies). |
1234 | some child status changes (most typically when a child of yours dies). |
1160 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
1235 | .IP "ev_child_init (ev_child *, callback, int pid)" 4 |
1161 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
1236 | .IX Item "ev_child_init (ev_child *, callback, int pid)" |
1162 | .PD 0 |
1237 | .PD 0 |
… | |
… | |
1167 | \&\fIany\fR process if \f(CW\*(C`pid\*(C'\fR is specified as \f(CW0\fR). The callback can look |
1242 | \&\fIany\fR process if \f(CW\*(C`pid\*(C'\fR is specified as \f(CW0\fR). The callback can look |
1168 | at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watcher structure to see |
1243 | at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watcher structure to see |
1169 | the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems |
1244 | the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems |
1170 | \&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the |
1245 | \&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the |
1171 | process causing the status change. |
1246 | process causing the status change. |
|
|
1247 | .IP "int pid [read\-only]" 4 |
|
|
1248 | .IX Item "int pid [read-only]" |
|
|
1249 | The process id this watcher watches out for, or \f(CW0\fR, meaning any process id. |
|
|
1250 | .IP "int rpid [read\-write]" 4 |
|
|
1251 | .IX Item "int rpid [read-write]" |
|
|
1252 | The process id that detected a status change. |
|
|
1253 | .IP "int rstatus [read\-write]" 4 |
|
|
1254 | .IX Item "int rstatus [read-write]" |
|
|
1255 | The process exit/trace status caused by \f(CW\*(C`rpid\*(C'\fR (see your systems |
|
|
1256 | \&\f(CW\*(C`waitpid\*(C'\fR and \f(CW\*(C`sys/wait.h\*(C'\fR documentation for details). |
1172 | .PP |
1257 | .PP |
1173 | Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
1258 | Example: try to exit cleanly on \s-1SIGINT\s0 and \s-1SIGTERM\s0. |
1174 | .PP |
1259 | .PP |
1175 | .Vb 5 |
1260 | .Vb 5 |
1176 | \& static void |
1261 | \& static void |
… | |
… | |
1183 | .Vb 3 |
1268 | .Vb 3 |
1184 | \& struct ev_signal signal_watcher; |
1269 | \& struct ev_signal signal_watcher; |
1185 | \& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1270 | \& ev_signal_init (&signal_watcher, sigint_cb, SIGINT); |
1186 | \& ev_signal_start (loop, &sigint_cb); |
1271 | \& ev_signal_start (loop, &sigint_cb); |
1187 | .Ve |
1272 | .Ve |
|
|
1273 | .ie n .Sh """ev_stat"" \- did the file attributes just change?" |
|
|
1274 | .el .Sh "\f(CWev_stat\fP \- did the file attributes just change?" |
|
|
1275 | .IX Subsection "ev_stat - did the file attributes just change?" |
|
|
1276 | This watches a filesystem path for attribute changes. That is, it calls |
|
|
1277 | \&\f(CW\*(C`stat\*(C'\fR regularly (or when the \s-1OS\s0 says it changed) and sees if it changed |
|
|
1278 | compared to the last time, invoking the callback if it did. |
|
|
1279 | .PP |
|
|
1280 | The path does not need to exist: changing from \*(L"path exists\*(R" to \*(L"path does |
|
|
1281 | not exist\*(R" is a status change like any other. The condition \*(L"path does |
|
|
1282 | not exist\*(R" is signified by the \f(CW\*(C`st_nlink\*(C'\fR field being zero (which is |
|
|
1283 | otherwise always forced to be at least one) and all the other fields of |
|
|
1284 | the stat buffer having unspecified contents. |
|
|
1285 | .PP |
|
|
1286 | Since there is no standard to do this, the portable implementation simply |
|
|
1287 | calls \f(CW\*(C`stat (2)\*(C'\fR regulalry on the path to see if it changed somehow. You |
|
|
1288 | can specify a recommended polling interval for this case. If you specify |
|
|
1289 | a polling interval of \f(CW0\fR (highly recommended!) then a \fIsuitable, |
|
|
1290 | unspecified default\fR value will be used (which you can expect to be around |
|
|
1291 | five seconds, although this might change dynamically). Libev will also |
|
|
1292 | impose a minimum interval which is currently around \f(CW0.1\fR, but thats |
|
|
1293 | usually overkill. |
|
|
1294 | .PP |
|
|
1295 | This watcher type is not meant for massive numbers of stat watchers, |
|
|
1296 | as even with OS-supported change notifications, this can be |
|
|
1297 | resource\-intensive. |
|
|
1298 | .PP |
|
|
1299 | At the time of this writing, no specific \s-1OS\s0 backends are implemented, but |
|
|
1300 | if demand increases, at least a kqueue and inotify backend will be added. |
|
|
1301 | .IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4 |
|
|
1302 | .IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" |
|
|
1303 | .PD 0 |
|
|
1304 | .IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4 |
|
|
1305 | .IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" |
|
|
1306 | .PD |
|
|
1307 | Configures the watcher to wait for status changes of the given |
|
|
1308 | \&\f(CW\*(C`path\*(C'\fR. The \f(CW\*(C`interval\*(C'\fR is a hint on how quickly a change is expected to |
|
|
1309 | be detected and should normally be specified as \f(CW0\fR to let libev choose |
|
|
1310 | a suitable value. The memory pointed to by \f(CW\*(C`path\*(C'\fR must point to the same |
|
|
1311 | path for as long as the watcher is active. |
|
|
1312 | .Sp |
|
|
1313 | The callback will be receive \f(CW\*(C`EV_STAT\*(C'\fR when a change was detected, |
|
|
1314 | relative to the attributes at the time the watcher was started (or the |
|
|
1315 | last change was detected). |
|
|
1316 | .IP "ev_stat_stat (ev_stat *)" 4 |
|
|
1317 | .IX Item "ev_stat_stat (ev_stat *)" |
|
|
1318 | Updates the stat buffer immediately with new values. If you change the |
|
|
1319 | watched path in your callback, you could call this fucntion to avoid |
|
|
1320 | detecting this change (while introducing a race condition). Can also be |
|
|
1321 | useful simply to find out the new values. |
|
|
1322 | .IP "ev_statdata attr [read\-only]" 4 |
|
|
1323 | .IX Item "ev_statdata attr [read-only]" |
|
|
1324 | The most-recently detected attributes of the file. Although the type is of |
|
|
1325 | \&\f(CW\*(C`ev_statdata\*(C'\fR, this is usually the (or one of the) \f(CW\*(C`struct stat\*(C'\fR types |
|
|
1326 | suitable for your system. If the \f(CW\*(C`st_nlink\*(C'\fR member is \f(CW0\fR, then there |
|
|
1327 | was some error while \f(CW\*(C`stat\*(C'\fRing the file. |
|
|
1328 | .IP "ev_statdata prev [read\-only]" 4 |
|
|
1329 | .IX Item "ev_statdata prev [read-only]" |
|
|
1330 | The previous attributes of the file. The callback gets invoked whenever |
|
|
1331 | \&\f(CW\*(C`prev\*(C'\fR != \f(CW\*(C`attr\*(C'\fR. |
|
|
1332 | .IP "ev_tstamp interval [read\-only]" 4 |
|
|
1333 | .IX Item "ev_tstamp interval [read-only]" |
|
|
1334 | The specified interval. |
|
|
1335 | .IP "const char *path [read\-only]" 4 |
|
|
1336 | .IX Item "const char *path [read-only]" |
|
|
1337 | The filesystem path that is being watched. |
|
|
1338 | .PP |
|
|
1339 | Example: Watch \f(CW\*(C`/etc/passwd\*(C'\fR for attribute changes. |
|
|
1340 | .PP |
|
|
1341 | .Vb 15 |
|
|
1342 | \& static void |
|
|
1343 | \& passwd_cb (struct ev_loop *loop, ev_stat *w, int revents) |
|
|
1344 | \& { |
|
|
1345 | \& /* /etc/passwd changed in some way */ |
|
|
1346 | \& if (w->attr.st_nlink) |
|
|
1347 | \& { |
|
|
1348 | \& printf ("passwd current size %ld\en", (long)w->attr.st_size); |
|
|
1349 | \& printf ("passwd current atime %ld\en", (long)w->attr.st_mtime); |
|
|
1350 | \& printf ("passwd current mtime %ld\en", (long)w->attr.st_mtime); |
|
|
1351 | \& } |
|
|
1352 | \& else |
|
|
1353 | \& /* you shalt not abuse printf for puts */ |
|
|
1354 | \& puts ("wow, /etc/passwd is not there, expect problems. " |
|
|
1355 | \& "if this is windows, they already arrived\en"); |
|
|
1356 | \& } |
|
|
1357 | .Ve |
|
|
1358 | .PP |
|
|
1359 | .Vb 2 |
|
|
1360 | \& ... |
|
|
1361 | \& ev_stat passwd; |
|
|
1362 | .Ve |
|
|
1363 | .PP |
|
|
1364 | .Vb 2 |
|
|
1365 | \& ev_stat_init (&passwd, passwd_cb, "/etc/passwd"); |
|
|
1366 | \& ev_stat_start (loop, &passwd); |
|
|
1367 | .Ve |
1188 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do" |
1368 | .ie n .Sh """ev_idle"" \- when you've got nothing better to do..." |
1189 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do" |
1369 | .el .Sh "\f(CWev_idle\fP \- when you've got nothing better to do..." |
1190 | .IX Subsection "ev_idle - when you've got nothing better to do" |
1370 | .IX Subsection "ev_idle - when you've got nothing better to do..." |
1191 | Idle watchers trigger events when there are no other events are pending |
1371 | Idle watchers trigger events when there are no other events are pending |
1192 | (prepare, check and other idle watchers do not count). That is, as long |
1372 | (prepare, check and other idle watchers do not count). That is, as long |
1193 | as your process is busy handling sockets or timeouts (or even signals, |
1373 | as your process is busy handling sockets or timeouts (or even signals, |
1194 | imagine) it will not be triggered. But when your process is idle all idle |
1374 | imagine) it will not be triggered. But when your process is idle all idle |
1195 | watchers are being called again and again, once per event loop iteration \- |
1375 | watchers are being called again and again, once per event loop iteration \- |
… | |
… | |
1225 | .Vb 3 |
1405 | .Vb 3 |
1226 | \& struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle)); |
1406 | \& struct ev_idle *idle_watcher = malloc (sizeof (struct ev_idle)); |
1227 | \& ev_idle_init (idle_watcher, idle_cb); |
1407 | \& ev_idle_init (idle_watcher, idle_cb); |
1228 | \& ev_idle_start (loop, idle_cb); |
1408 | \& ev_idle_start (loop, idle_cb); |
1229 | .Ve |
1409 | .Ve |
1230 | .ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop" |
1410 | .ie n .Sh """ev_prepare""\fP and \f(CW""ev_check"" \- customise your event loop!" |
1231 | .el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop" |
1411 | .el .Sh "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop!" |
1232 | .IX Subsection "ev_prepare and ev_check - customise your event loop" |
1412 | .IX Subsection "ev_prepare and ev_check - customise your event loop!" |
1233 | Prepare and check watchers are usually (but not always) used in tandem: |
1413 | Prepare and check watchers are usually (but not always) used in tandem: |
1234 | prepare watchers get invoked before the process blocks and check watchers |
1414 | prepare watchers get invoked before the process blocks and check watchers |
1235 | afterwards. |
1415 | afterwards. |
1236 | .PP |
1416 | .PP |
|
|
1417 | You \fImust not\fR call \f(CW\*(C`ev_loop\*(C'\fR or similar functions that enter |
|
|
1418 | the current event loop from either \f(CW\*(C`ev_prepare\*(C'\fR or \f(CW\*(C`ev_check\*(C'\fR |
|
|
1419 | watchers. Other loops than the current one are fine, however. The |
|
|
1420 | rationale behind this is that you do not need to check for recursion in |
|
|
1421 | those watchers, i.e. the sequence will always be \f(CW\*(C`ev_prepare\*(C'\fR, blocking, |
|
|
1422 | \&\f(CW\*(C`ev_check\*(C'\fR so if you have one watcher of each kind they will always be |
|
|
1423 | called in pairs bracketing the blocking call. |
|
|
1424 | .PP |
1237 | Their main purpose is to integrate other event mechanisms into libev and |
1425 | Their main purpose is to integrate other event mechanisms into libev and |
1238 | their use is somewhat advanced. This could be used, for example, to track |
1426 | their use is somewhat advanced. This could be used, for example, to track |
1239 | variable changes, implement your own watchers, integrate net-snmp or a |
1427 | variable changes, implement your own watchers, integrate net-snmp or a |
1240 | coroutine library and lots more. |
1428 | coroutine library and lots more. They are also occasionally useful if |
|
|
1429 | you cache some data and want to flush it before blocking (for example, |
|
|
1430 | in X programs you might want to do an \f(CW\*(C`XFlush ()\*(C'\fR in an \f(CW\*(C`ev_prepare\*(C'\fR |
|
|
1431 | watcher). |
1241 | .PP |
1432 | .PP |
1242 | This is done by examining in each prepare call which file descriptors need |
1433 | This is done by examining in each prepare call which file descriptors need |
1243 | to be watched by the other library, registering \f(CW\*(C`ev_io\*(C'\fR watchers for |
1434 | to be watched by the other library, registering \f(CW\*(C`ev_io\*(C'\fR watchers for |
1244 | them and starting an \f(CW\*(C`ev_timer\*(C'\fR watcher for any timeouts (many libraries |
1435 | them and starting an \f(CW\*(C`ev_timer\*(C'\fR watcher for any timeouts (many libraries |
1245 | provide just this functionality). Then, in the check watcher you check for |
1436 | provide just this functionality). Then, in the check watcher you check for |
… | |
… | |
1264 | .PD |
1455 | .PD |
1265 | Initialises and configures the prepare or check watcher \- they have no |
1456 | Initialises and configures the prepare or check watcher \- they have no |
1266 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1457 | parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR |
1267 | macros, but using them is utterly, utterly and completely pointless. |
1458 | macros, but using them is utterly, utterly and completely pointless. |
1268 | .PP |
1459 | .PP |
1269 | Example: *TODO*. |
1460 | Example: To include a library such as adns, you would add \s-1IO\s0 watchers |
|
|
1461 | and a timeout watcher in a prepare handler, as required by libadns, and |
|
|
1462 | in a check watcher, destroy them and call into libadns. What follows is |
|
|
1463 | pseudo-code only of course: |
|
|
1464 | .PP |
|
|
1465 | .Vb 2 |
|
|
1466 | \& static ev_io iow [nfd]; |
|
|
1467 | \& static ev_timer tw; |
|
|
1468 | .Ve |
|
|
1469 | .PP |
|
|
1470 | .Vb 9 |
|
|
1471 | \& static void |
|
|
1472 | \& io_cb (ev_loop *loop, ev_io *w, int revents) |
|
|
1473 | \& { |
|
|
1474 | \& // set the relevant poll flags |
|
|
1475 | \& // could also call adns_processreadable etc. here |
|
|
1476 | \& struct pollfd *fd = (struct pollfd *)w->data; |
|
|
1477 | \& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN; |
|
|
1478 | \& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT; |
|
|
1479 | \& } |
|
|
1480 | .Ve |
|
|
1481 | .PP |
|
|
1482 | .Vb 7 |
|
|
1483 | \& // create io watchers for each fd and a timer before blocking |
|
|
1484 | \& static void |
|
|
1485 | \& adns_prepare_cb (ev_loop *loop, ev_prepare *w, int revents) |
|
|
1486 | \& { |
|
|
1487 | \& int timeout = 3600000;truct pollfd fds [nfd]; |
|
|
1488 | \& // actual code will need to loop here and realloc etc. |
|
|
1489 | \& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ())); |
|
|
1490 | .Ve |
|
|
1491 | .PP |
|
|
1492 | .Vb 3 |
|
|
1493 | \& /* the callback is illegal, but won't be called as we stop during check */ |
|
|
1494 | \& ev_timer_init (&tw, 0, timeout * 1e-3); |
|
|
1495 | \& ev_timer_start (loop, &tw); |
|
|
1496 | .Ve |
|
|
1497 | .PP |
|
|
1498 | .Vb 6 |
|
|
1499 | \& // create on ev_io per pollfd |
|
|
1500 | \& for (int i = 0; i < nfd; ++i) |
|
|
1501 | \& { |
|
|
1502 | \& ev_io_init (iow + i, io_cb, fds [i].fd, |
|
|
1503 | \& ((fds [i].events & POLLIN ? EV_READ : 0) |
|
|
1504 | \& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); |
|
|
1505 | .Ve |
|
|
1506 | .PP |
|
|
1507 | .Vb 5 |
|
|
1508 | \& fds [i].revents = 0; |
|
|
1509 | \& iow [i].data = fds + i; |
|
|
1510 | \& ev_io_start (loop, iow + i); |
|
|
1511 | \& } |
|
|
1512 | \& } |
|
|
1513 | .Ve |
|
|
1514 | .PP |
|
|
1515 | .Vb 5 |
|
|
1516 | \& // stop all watchers after blocking |
|
|
1517 | \& static void |
|
|
1518 | \& adns_check_cb (ev_loop *loop, ev_check *w, int revents) |
|
|
1519 | \& { |
|
|
1520 | \& ev_timer_stop (loop, &tw); |
|
|
1521 | .Ve |
|
|
1522 | .PP |
|
|
1523 | .Vb 2 |
|
|
1524 | \& for (int i = 0; i < nfd; ++i) |
|
|
1525 | \& ev_io_stop (loop, iow + i); |
|
|
1526 | .Ve |
|
|
1527 | .PP |
|
|
1528 | .Vb 2 |
|
|
1529 | \& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); |
|
|
1530 | \& } |
|
|
1531 | .Ve |
1270 | .ie n .Sh """ev_embed"" \- when one backend isn't enough" |
1532 | .ie n .Sh """ev_embed"" \- when one backend isn't enough..." |
1271 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough" |
1533 | .el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." |
1272 | .IX Subsection "ev_embed - when one backend isn't enough" |
1534 | .IX Subsection "ev_embed - when one backend isn't enough..." |
1273 | This is a rather advanced watcher type that lets you embed one event loop |
1535 | This is a rather advanced watcher type that lets you embed one event loop |
1274 | into another (currently only \f(CW\*(C`ev_io\*(C'\fR events are supported in the embedded |
1536 | into another (currently only \f(CW\*(C`ev_io\*(C'\fR events are supported in the embedded |
1275 | loop, other types of watchers might be handled in a delayed or incorrect |
1537 | loop, other types of watchers might be handled in a delayed or incorrect |
1276 | fashion and must not be used). |
1538 | fashion and must not be used). |
1277 | .PP |
1539 | .PP |
… | |
… | |
1357 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
1619 | .IP "ev_embed_sweep (loop, ev_embed *)" 4 |
1358 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
1620 | .IX Item "ev_embed_sweep (loop, ev_embed *)" |
1359 | Make a single, non-blocking sweep over the embedded loop. This works |
1621 | Make a single, non-blocking sweep over the embedded loop. This works |
1360 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
1622 | similarly to \f(CW\*(C`ev_loop (embedded_loop, EVLOOP_NONBLOCK)\*(C'\fR, but in the most |
1361 | apropriate way for embedded loops. |
1623 | apropriate way for embedded loops. |
|
|
1624 | .IP "struct ev_loop *loop [read\-only]" 4 |
|
|
1625 | .IX Item "struct ev_loop *loop [read-only]" |
|
|
1626 | The embedded event loop. |
|
|
1627 | .ie n .Sh """ev_fork"" \- the audacity to resume the event loop after a fork" |
|
|
1628 | .el .Sh "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork" |
|
|
1629 | .IX Subsection "ev_fork - the audacity to resume the event loop after a fork" |
|
|
1630 | Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because |
|
|
1631 | whoever is a good citizen cared to tell libev about it by calling |
|
|
1632 | \&\f(CW\*(C`ev_default_fork\*(C'\fR or \f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the |
|
|
1633 | event loop blocks next and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called, |
|
|
1634 | and only in the child after the fork. If whoever good citizen calling |
|
|
1635 | \&\f(CW\*(C`ev_default_fork\*(C'\fR cheats and calls it in the wrong process, the fork |
|
|
1636 | handlers will be invoked, too, of course. |
|
|
1637 | .IP "ev_fork_init (ev_signal *, callback)" 4 |
|
|
1638 | .IX Item "ev_fork_init (ev_signal *, callback)" |
|
|
1639 | Initialises and configures the fork watcher \- it has no parameters of any |
|
|
1640 | kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless, |
|
|
1641 | believe me. |
1362 | .SH "OTHER FUNCTIONS" |
1642 | .SH "OTHER FUNCTIONS" |
1363 | .IX Header "OTHER FUNCTIONS" |
1643 | .IX Header "OTHER FUNCTIONS" |
1364 | There are some other functions of possible interest. Described. Here. Now. |
1644 | There are some other functions of possible interest. Described. Here. Now. |
1365 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
1645 | .IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4 |
1366 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
1646 | .IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" |
… | |
… | |
1428 | .IP "* The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need to use the libev header file and library." 4 |
1708 | .IP "* The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need to use the libev header file and library." 4 |
1429 | .IX Item "The libev emulation is not ABI compatible to libevent, you need to use the libev header file and library." |
1709 | .IX Item "The libev emulation is not ABI compatible to libevent, you need to use the libev header file and library." |
1430 | .PD |
1710 | .PD |
1431 | .SH "\*(C+ SUPPORT" |
1711 | .SH "\*(C+ SUPPORT" |
1432 | .IX Header " SUPPORT" |
1712 | .IX Header " SUPPORT" |
1433 | \&\s-1TBD\s0. |
1713 | Libev comes with some simplistic wrapper classes for \*(C+ that mainly allow |
|
|
1714 | you to use some convinience methods to start/stop watchers and also change |
|
|
1715 | the callback model to a model using method callbacks on objects. |
|
|
1716 | .PP |
|
|
1717 | To use it, |
|
|
1718 | .PP |
|
|
1719 | .Vb 1 |
|
|
1720 | \& #include <ev++.h> |
|
|
1721 | .Ve |
|
|
1722 | .PP |
|
|
1723 | (it is not installed by default). This automatically includes \fIev.h\fR |
|
|
1724 | and puts all of its definitions (many of them macros) into the global |
|
|
1725 | namespace. All \*(C+ specific things are put into the \f(CW\*(C`ev\*(C'\fR namespace. |
|
|
1726 | .PP |
|
|
1727 | It should support all the same embedding options as \fIev.h\fR, most notably |
|
|
1728 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
|
|
1729 | .PP |
|
|
1730 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
|
|
1731 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
|
|
1732 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
|
|
1733 | .IX Item "ev::READ, ev::WRITE etc." |
|
|
1734 | These are just enum values with the same values as the \f(CW\*(C`EV_READ\*(C'\fR etc. |
|
|
1735 | macros from \fIev.h\fR. |
|
|
1736 | .ie n .IP """ev::tstamp""\fR, \f(CW""ev::now""" 4 |
|
|
1737 | .el .IP "\f(CWev::tstamp\fR, \f(CWev::now\fR" 4 |
|
|
1738 | .IX Item "ev::tstamp, ev::now" |
|
|
1739 | Aliases to the same types/functions as with the \f(CW\*(C`ev_\*(C'\fR prefix. |
|
|
1740 | .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 |
|
|
1741 | .el .IP "\f(CWev::io\fR, \f(CWev::timer\fR, \f(CWev::periodic\fR, \f(CWev::idle\fR, \f(CWev::sig\fR etc." 4 |
|
|
1742 | .IX Item "ev::io, ev::timer, ev::periodic, ev::idle, ev::sig etc." |
|
|
1743 | For each \f(CW\*(C`ev_TYPE\*(C'\fR watcher in \fIev.h\fR there is a corresponding class of |
|
|
1744 | the same name in the \f(CW\*(C`ev\*(C'\fR namespace, with the exception of \f(CW\*(C`ev_signal\*(C'\fR |
|
|
1745 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
|
|
1746 | defines by many implementations. |
|
|
1747 | .Sp |
|
|
1748 | All of those classes have these methods: |
|
|
1749 | .RS 4 |
|
|
1750 | .IP "ev::TYPE::TYPE (object *, object::method *)" 4 |
|
|
1751 | .IX Item "ev::TYPE::TYPE (object *, object::method *)" |
|
|
1752 | .PD 0 |
|
|
1753 | .IP "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" 4 |
|
|
1754 | .IX Item "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" |
|
|
1755 | .IP "ev::TYPE::~TYPE" 4 |
|
|
1756 | .IX Item "ev::TYPE::~TYPE" |
|
|
1757 | .PD |
|
|
1758 | The constructor takes a pointer to an object and a method pointer to |
|
|
1759 | the event handler callback to call in this class. The constructor calls |
|
|
1760 | \&\f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the \f(CW\*(C`set\*(C'\fR method |
|
|
1761 | before starting it. If you do not specify a loop then the constructor |
|
|
1762 | automatically associates the default loop with this watcher. |
|
|
1763 | .Sp |
|
|
1764 | The destructor automatically stops the watcher if it is active. |
|
|
1765 | .IP "w\->set (struct ev_loop *)" 4 |
|
|
1766 | .IX Item "w->set (struct ev_loop *)" |
|
|
1767 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
|
|
1768 | do this when the watcher is inactive (and not pending either). |
|
|
1769 | .IP "w\->set ([args])" 4 |
|
|
1770 | .IX Item "w->set ([args])" |
|
|
1771 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
|
|
1772 | called at least once. Unlike the C counterpart, an active watcher gets |
|
|
1773 | automatically stopped and restarted. |
|
|
1774 | .IP "w\->start ()" 4 |
|
|
1775 | .IX Item "w->start ()" |
|
|
1776 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument as the |
|
|
1777 | constructor already takes the loop. |
|
|
1778 | .IP "w\->stop ()" 4 |
|
|
1779 | .IX Item "w->stop ()" |
|
|
1780 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
|
|
1781 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
|
|
1782 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
|
|
1783 | .IX Item "w->again () ev::timer, ev::periodic only" |
|
|
1784 | For \f(CW\*(C`ev::timer\*(C'\fR and \f(CW\*(C`ev::periodic\*(C'\fR, this invokes the corresponding |
|
|
1785 | \&\f(CW\*(C`ev_TYPE_again\*(C'\fR function. |
|
|
1786 | .ie n .IP "w\->sweep () ""ev::embed"" only" 4 |
|
|
1787 | .el .IP "w\->sweep () \f(CWev::embed\fR only" 4 |
|
|
1788 | .IX Item "w->sweep () ev::embed only" |
|
|
1789 | Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR. |
|
|
1790 | .ie n .IP "w\->update () ""ev::stat"" only" 4 |
|
|
1791 | .el .IP "w\->update () \f(CWev::stat\fR only" 4 |
|
|
1792 | .IX Item "w->update () ev::stat only" |
|
|
1793 | Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR. |
|
|
1794 | .RE |
|
|
1795 | .RS 4 |
|
|
1796 | .RE |
|
|
1797 | .PP |
|
|
1798 | Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in |
|
|
1799 | the constructor. |
|
|
1800 | .PP |
|
|
1801 | .Vb 4 |
|
|
1802 | \& class myclass |
|
|
1803 | \& { |
|
|
1804 | \& ev_io io; void io_cb (ev::io &w, int revents); |
|
|
1805 | \& ev_idle idle void idle_cb (ev::idle &w, int revents); |
|
|
1806 | .Ve |
|
|
1807 | .PP |
|
|
1808 | .Vb 2 |
|
|
1809 | \& myclass (); |
|
|
1810 | \& } |
|
|
1811 | .Ve |
|
|
1812 | .PP |
|
|
1813 | .Vb 6 |
|
|
1814 | \& myclass::myclass (int fd) |
|
|
1815 | \& : io (this, &myclass::io_cb), |
|
|
1816 | \& idle (this, &myclass::idle_cb) |
|
|
1817 | \& { |
|
|
1818 | \& io.start (fd, ev::READ); |
|
|
1819 | \& } |
|
|
1820 | .Ve |
|
|
1821 | .SH "MACRO MAGIC" |
|
|
1822 | .IX Header "MACRO MAGIC" |
|
|
1823 | Libev can be compiled with a variety of options, the most fundemantal is |
|
|
1824 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines wether (most) functions and |
|
|
1825 | callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
|
|
1826 | .PP |
|
|
1827 | To make it easier to write programs that cope with either variant, the |
|
|
1828 | following macros are defined: |
|
|
1829 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
|
|
1830 | .el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4 |
|
|
1831 | .IX Item "EV_A, EV_A_" |
|
|
1832 | This provides the loop \fIargument\fR for functions, if one is required (\*(L"ev |
|
|
1833 | loop argument\*(R"). The \f(CW\*(C`EV_A\*(C'\fR form is used when this is the sole argument, |
|
|
1834 | \&\f(CW\*(C`EV_A_\*(C'\fR is used when other arguments are following. Example: |
|
|
1835 | .Sp |
|
|
1836 | .Vb 3 |
|
|
1837 | \& ev_unref (EV_A); |
|
|
1838 | \& ev_timer_add (EV_A_ watcher); |
|
|
1839 | \& ev_loop (EV_A_ 0); |
|
|
1840 | .Ve |
|
|
1841 | .Sp |
|
|
1842 | It assumes the variable \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR is in scope, |
|
|
1843 | which is often provided by the following macro. |
|
|
1844 | .ie n .IP """EV_P""\fR, \f(CW""EV_P_""" 4 |
|
|
1845 | .el .IP "\f(CWEV_P\fR, \f(CWEV_P_\fR" 4 |
|
|
1846 | .IX Item "EV_P, EV_P_" |
|
|
1847 | This provides the loop \fIparameter\fR for functions, if one is required (\*(L"ev |
|
|
1848 | loop parameter\*(R"). The \f(CW\*(C`EV_P\*(C'\fR form is used when this is the sole parameter, |
|
|
1849 | \&\f(CW\*(C`EV_P_\*(C'\fR is used when other parameters are following. Example: |
|
|
1850 | .Sp |
|
|
1851 | .Vb 2 |
|
|
1852 | \& // this is how ev_unref is being declared |
|
|
1853 | \& static void ev_unref (EV_P); |
|
|
1854 | .Ve |
|
|
1855 | .Sp |
|
|
1856 | .Vb 2 |
|
|
1857 | \& // this is how you can declare your typical callback |
|
|
1858 | \& static void cb (EV_P_ ev_timer *w, int revents) |
|
|
1859 | .Ve |
|
|
1860 | .Sp |
|
|
1861 | It declares a parameter \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR, quite |
|
|
1862 | suitable for use with \f(CW\*(C`EV_A\*(C'\fR. |
|
|
1863 | .ie n .IP """EV_DEFAULT""\fR, \f(CW""EV_DEFAULT_""" 4 |
|
|
1864 | .el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4 |
|
|
1865 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
|
|
1866 | Similar to the other two macros, this gives you the value of the default |
|
|
1867 | loop, if multiple loops are supported (\*(L"ev loop default\*(R"). |
|
|
1868 | .PP |
|
|
1869 | Example: Declare and initialise a check watcher, working regardless of |
|
|
1870 | wether multiple loops are supported or not. |
|
|
1871 | .PP |
|
|
1872 | .Vb 5 |
|
|
1873 | \& static void |
|
|
1874 | \& check_cb (EV_P_ ev_timer *w, int revents) |
|
|
1875 | \& { |
|
|
1876 | \& ev_check_stop (EV_A_ w); |
|
|
1877 | \& } |
|
|
1878 | .Ve |
|
|
1879 | .PP |
|
|
1880 | .Vb 4 |
|
|
1881 | \& ev_check check; |
|
|
1882 | \& ev_check_init (&check, check_cb); |
|
|
1883 | \& ev_check_start (EV_DEFAULT_ &check); |
|
|
1884 | \& ev_loop (EV_DEFAULT_ 0); |
|
|
1885 | .Ve |
|
|
1886 | .SH "EMBEDDING" |
|
|
1887 | .IX Header "EMBEDDING" |
|
|
1888 | Libev can (and often is) directly embedded into host |
|
|
1889 | applications. Examples of applications that embed it include the Deliantra |
|
|
1890 | Game Server, the \s-1EV\s0 perl module, the \s-1GNU\s0 Virtual Private Ethernet (gvpe) |
|
|
1891 | and rxvt\-unicode. |
|
|
1892 | .PP |
|
|
1893 | The goal is to enable you to just copy the neecssary files into your |
|
|
1894 | source directory without having to change even a single line in them, so |
|
|
1895 | you can easily upgrade by simply copying (or having a checked-out copy of |
|
|
1896 | libev somewhere in your source tree). |
|
|
1897 | .Sh "\s-1FILESETS\s0" |
|
|
1898 | .IX Subsection "FILESETS" |
|
|
1899 | Depending on what features you need you need to include one or more sets of files |
|
|
1900 | in your app. |
|
|
1901 | .PP |
|
|
1902 | \fI\s-1CORE\s0 \s-1EVENT\s0 \s-1LOOP\s0\fR |
|
|
1903 | .IX Subsection "CORE EVENT LOOP" |
|
|
1904 | .PP |
|
|
1905 | To include only the libev core (all the \f(CW\*(C`ev_*\*(C'\fR functions), with manual |
|
|
1906 | configuration (no autoconf): |
|
|
1907 | .PP |
|
|
1908 | .Vb 2 |
|
|
1909 | \& #define EV_STANDALONE 1 |
|
|
1910 | \& #include "ev.c" |
|
|
1911 | .Ve |
|
|
1912 | .PP |
|
|
1913 | This will automatically include \fIev.h\fR, too, and should be done in a |
|
|
1914 | single C source file only to provide the function implementations. To use |
|
|
1915 | it, do the same for \fIev.h\fR in all files wishing to use this \s-1API\s0 (best |
|
|
1916 | done by writing a wrapper around \fIev.h\fR that you can include instead and |
|
|
1917 | where you can put other configuration options): |
|
|
1918 | .PP |
|
|
1919 | .Vb 2 |
|
|
1920 | \& #define EV_STANDALONE 1 |
|
|
1921 | \& #include "ev.h" |
|
|
1922 | .Ve |
|
|
1923 | .PP |
|
|
1924 | Both header files and implementation files can be compiled with a \*(C+ |
|
|
1925 | compiler (at least, thats a stated goal, and breakage will be treated |
|
|
1926 | as a bug). |
|
|
1927 | .PP |
|
|
1928 | You need the following files in your source tree, or in a directory |
|
|
1929 | in your include path (e.g. in libev/ when using \-Ilibev): |
|
|
1930 | .PP |
|
|
1931 | .Vb 4 |
|
|
1932 | \& ev.h |
|
|
1933 | \& ev.c |
|
|
1934 | \& ev_vars.h |
|
|
1935 | \& ev_wrap.h |
|
|
1936 | .Ve |
|
|
1937 | .PP |
|
|
1938 | .Vb 1 |
|
|
1939 | \& ev_win32.c required on win32 platforms only |
|
|
1940 | .Ve |
|
|
1941 | .PP |
|
|
1942 | .Vb 5 |
|
|
1943 | \& ev_select.c only when select backend is enabled (which is by default) |
|
|
1944 | \& ev_poll.c only when poll backend is enabled (disabled by default) |
|
|
1945 | \& ev_epoll.c only when the epoll backend is enabled (disabled by default) |
|
|
1946 | \& ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
|
|
1947 | \& ev_port.c only when the solaris port backend is enabled (disabled by default) |
|
|
1948 | .Ve |
|
|
1949 | .PP |
|
|
1950 | \&\fIev.c\fR includes the backend files directly when enabled, so you only need |
|
|
1951 | to compile this single file. |
|
|
1952 | .PP |
|
|
1953 | \fI\s-1LIBEVENT\s0 \s-1COMPATIBILITY\s0 \s-1API\s0\fR |
|
|
1954 | .IX Subsection "LIBEVENT COMPATIBILITY API" |
|
|
1955 | .PP |
|
|
1956 | To include the libevent compatibility \s-1API\s0, also include: |
|
|
1957 | .PP |
|
|
1958 | .Vb 1 |
|
|
1959 | \& #include "event.c" |
|
|
1960 | .Ve |
|
|
1961 | .PP |
|
|
1962 | in the file including \fIev.c\fR, and: |
|
|
1963 | .PP |
|
|
1964 | .Vb 1 |
|
|
1965 | \& #include "event.h" |
|
|
1966 | .Ve |
|
|
1967 | .PP |
|
|
1968 | in the files that want to use the libevent \s-1API\s0. This also includes \fIev.h\fR. |
|
|
1969 | .PP |
|
|
1970 | You need the following additional files for this: |
|
|
1971 | .PP |
|
|
1972 | .Vb 2 |
|
|
1973 | \& event.h |
|
|
1974 | \& event.c |
|
|
1975 | .Ve |
|
|
1976 | .PP |
|
|
1977 | \fI\s-1AUTOCONF\s0 \s-1SUPPORT\s0\fR |
|
|
1978 | .IX Subsection "AUTOCONF SUPPORT" |
|
|
1979 | .PP |
|
|
1980 | Instead of using \f(CW\*(C`EV_STANDALONE=1\*(C'\fR and providing your config in |
|
|
1981 | whatever way you want, you can also \f(CW\*(C`m4_include([libev.m4])\*(C'\fR in your |
|
|
1982 | \&\fIconfigure.ac\fR and leave \f(CW\*(C`EV_STANDALONE\*(C'\fR undefined. \fIev.c\fR will then |
|
|
1983 | include \fIconfig.h\fR and configure itself accordingly. |
|
|
1984 | .PP |
|
|
1985 | For this of course you need the m4 file: |
|
|
1986 | .PP |
|
|
1987 | .Vb 1 |
|
|
1988 | \& libev.m4 |
|
|
1989 | .Ve |
|
|
1990 | .Sh "\s-1PREPROCESSOR\s0 \s-1SYMBOLS/MACROS\s0" |
|
|
1991 | .IX Subsection "PREPROCESSOR SYMBOLS/MACROS" |
|
|
1992 | Libev can be configured via a variety of preprocessor symbols you have to define |
|
|
1993 | before including any of its files. The default is not to build for multiplicity |
|
|
1994 | and only include the select backend. |
|
|
1995 | .IP "\s-1EV_STANDALONE\s0" 4 |
|
|
1996 | .IX Item "EV_STANDALONE" |
|
|
1997 | Must always be \f(CW1\fR if you do not use autoconf configuration, which |
|
|
1998 | keeps libev from including \fIconfig.h\fR, and it also defines dummy |
|
|
1999 | implementations for some libevent functions (such as logging, which is not |
|
|
2000 | supported). It will also not define any of the structs usually found in |
|
|
2001 | \&\fIevent.h\fR that are not directly supported by the libev core alone. |
|
|
2002 | .IP "\s-1EV_USE_MONOTONIC\s0" 4 |
|
|
2003 | .IX Item "EV_USE_MONOTONIC" |
|
|
2004 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
|
|
2005 | monotonic clock option at both compiletime and runtime. Otherwise no use |
|
|
2006 | of the monotonic clock option will be attempted. If you enable this, you |
|
|
2007 | usually have to link against librt or something similar. Enabling it when |
|
|
2008 | the functionality isn't available is safe, though, althoguh you have |
|
|
2009 | to make sure you link against any libraries where the \f(CW\*(C`clock_gettime\*(C'\fR |
|
|
2010 | function is hiding in (often \fI\-lrt\fR). |
|
|
2011 | .IP "\s-1EV_USE_REALTIME\s0" 4 |
|
|
2012 | .IX Item "EV_USE_REALTIME" |
|
|
2013 | If defined to be \f(CW1\fR, libev will try to detect the availability of the |
|
|
2014 | realtime clock option at compiletime (and assume its availability at |
|
|
2015 | runtime if successful). Otherwise no use of the realtime clock option will |
|
|
2016 | be attempted. This effectively replaces \f(CW\*(C`gettimeofday\*(C'\fR by \f(CW\*(C`clock_get |
|
|
2017 | (CLOCK_REALTIME, ...)\*(C'\fR and will not normally affect correctness. See tzhe note about libraries |
|
|
2018 | in the description of \f(CW\*(C`EV_USE_MONOTONIC\*(C'\fR, though. |
|
|
2019 | .IP "\s-1EV_USE_SELECT\s0" 4 |
|
|
2020 | .IX Item "EV_USE_SELECT" |
|
|
2021 | If undefined or defined to be \f(CW1\fR, libev will compile in support for the |
|
|
2022 | \&\f(CW\*(C`select\*(C'\fR(2) backend. No attempt at autodetection will be done: if no |
|
|
2023 | other method takes over, select will be it. Otherwise the select backend |
|
|
2024 | will not be compiled in. |
|
|
2025 | .IP "\s-1EV_SELECT_USE_FD_SET\s0" 4 |
|
|
2026 | .IX Item "EV_SELECT_USE_FD_SET" |
|
|
2027 | If defined to \f(CW1\fR, then the select backend will use the system \f(CW\*(C`fd_set\*(C'\fR |
|
|
2028 | structure. This is useful if libev doesn't compile due to a missing |
|
|
2029 | \&\f(CW\*(C`NFDBITS\*(C'\fR or \f(CW\*(C`fd_mask\*(C'\fR definition or it misguesses the bitset layout on |
|
|
2030 | exotic systems. This usually limits the range of file descriptors to some |
|
|
2031 | low limit such as 1024 or might have other limitations (winsocket only |
|
|
2032 | allows 64 sockets). The \f(CW\*(C`FD_SETSIZE\*(C'\fR macro, set before compilation, might |
|
|
2033 | influence the size of the \f(CW\*(C`fd_set\*(C'\fR used. |
|
|
2034 | .IP "\s-1EV_SELECT_IS_WINSOCKET\s0" 4 |
|
|
2035 | .IX Item "EV_SELECT_IS_WINSOCKET" |
|
|
2036 | When defined to \f(CW1\fR, the select backend will assume that |
|
|
2037 | select/socket/connect etc. don't understand file descriptors but |
|
|
2038 | wants osf handles on win32 (this is the case when the select to |
|
|
2039 | be used is the winsock select). This means that it will call |
|
|
2040 | \&\f(CW\*(C`_get_osfhandle\*(C'\fR on the fd to convert it to an \s-1OS\s0 handle. Otherwise, |
|
|
2041 | it is assumed that all these functions actually work on fds, even |
|
|
2042 | on win32. Should not be defined on non\-win32 platforms. |
|
|
2043 | .IP "\s-1EV_USE_POLL\s0" 4 |
|
|
2044 | .IX Item "EV_USE_POLL" |
|
|
2045 | If defined to be \f(CW1\fR, libev will compile in support for the \f(CW\*(C`poll\*(C'\fR(2) |
|
|
2046 | backend. Otherwise it will be enabled on non\-win32 platforms. It |
|
|
2047 | takes precedence over select. |
|
|
2048 | .IP "\s-1EV_USE_EPOLL\s0" 4 |
|
|
2049 | .IX Item "EV_USE_EPOLL" |
|
|
2050 | If defined to be \f(CW1\fR, libev will compile in support for the Linux |
|
|
2051 | \&\f(CW\*(C`epoll\*(C'\fR(7) backend. Its availability will be detected at runtime, |
|
|
2052 | otherwise another method will be used as fallback. This is the |
|
|
2053 | preferred backend for GNU/Linux systems. |
|
|
2054 | .IP "\s-1EV_USE_KQUEUE\s0" 4 |
|
|
2055 | .IX Item "EV_USE_KQUEUE" |
|
|
2056 | If defined to be \f(CW1\fR, libev will compile in support for the \s-1BSD\s0 style |
|
|
2057 | \&\f(CW\*(C`kqueue\*(C'\fR(2) backend. Its actual availability will be detected at runtime, |
|
|
2058 | otherwise another method will be used as fallback. This is the preferred |
|
|
2059 | backend for \s-1BSD\s0 and BSD-like systems, although on most BSDs kqueue only |
|
|
2060 | supports some types of fds correctly (the only platform we found that |
|
|
2061 | supports ptys for example was NetBSD), so kqueue might be compiled in, but |
|
|
2062 | not be used unless explicitly requested. The best way to use it is to find |
|
|
2063 | out whether kqueue supports your type of fd properly and use an embedded |
|
|
2064 | kqueue loop. |
|
|
2065 | .IP "\s-1EV_USE_PORT\s0" 4 |
|
|
2066 | .IX Item "EV_USE_PORT" |
|
|
2067 | If defined to be \f(CW1\fR, libev will compile in support for the Solaris |
|
|
2068 | 10 port style backend. Its availability will be detected at runtime, |
|
|
2069 | otherwise another method will be used as fallback. This is the preferred |
|
|
2070 | backend for Solaris 10 systems. |
|
|
2071 | .IP "\s-1EV_USE_DEVPOLL\s0" 4 |
|
|
2072 | .IX Item "EV_USE_DEVPOLL" |
|
|
2073 | reserved for future expansion, works like the \s-1USE\s0 symbols above. |
|
|
2074 | .IP "\s-1EV_H\s0" 4 |
|
|
2075 | .IX Item "EV_H" |
|
|
2076 | The name of the \fIev.h\fR header file used to include it. The default if |
|
|
2077 | undefined is \f(CW\*(C`<ev.h>\*(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This |
|
|
2078 | can be used to virtually rename the \fIev.h\fR header file in case of conflicts. |
|
|
2079 | .IP "\s-1EV_CONFIG_H\s0" 4 |
|
|
2080 | .IX Item "EV_CONFIG_H" |
|
|
2081 | If \f(CW\*(C`EV_STANDALONE\*(C'\fR isn't \f(CW1\fR, this variable can be used to override |
|
|
2082 | \&\fIev.c\fR's idea of where to find the \fIconfig.h\fR file, similarly to |
|
|
2083 | \&\f(CW\*(C`EV_H\*(C'\fR, above. |
|
|
2084 | .IP "\s-1EV_EVENT_H\s0" 4 |
|
|
2085 | .IX Item "EV_EVENT_H" |
|
|
2086 | Similarly to \f(CW\*(C`EV_H\*(C'\fR, this macro can be used to override \fIevent.c\fR's idea |
|
|
2087 | of how the \fIevent.h\fR header can be found. |
|
|
2088 | .IP "\s-1EV_PROTOTYPES\s0" 4 |
|
|
2089 | .IX Item "EV_PROTOTYPES" |
|
|
2090 | If defined to be \f(CW0\fR, then \fIev.h\fR will not define any function |
|
|
2091 | prototypes, but still define all the structs and other symbols. This is |
|
|
2092 | occasionally useful if you want to provide your own wrapper functions |
|
|
2093 | around libev functions. |
|
|
2094 | .IP "\s-1EV_MULTIPLICITY\s0" 4 |
|
|
2095 | .IX Item "EV_MULTIPLICITY" |
|
|
2096 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
|
|
2097 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
|
|
2098 | additional independent event loops. Otherwise there will be no support |
|
|
2099 | for multiple event loops and there is no first event loop pointer |
|
|
2100 | argument. Instead, all functions act on the single default loop. |
|
|
2101 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
|
|
2102 | .IX Item "EV_PERIODIC_ENABLE" |
|
|
2103 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
|
|
2104 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
|
|
2105 | code. |
|
|
2106 | .IP "\s-1EV_EMBED_ENABLE\s0" 4 |
|
|
2107 | .IX Item "EV_EMBED_ENABLE" |
|
|
2108 | If undefined or defined to be \f(CW1\fR, then embed watchers are supported. If |
|
|
2109 | defined to be \f(CW0\fR, then they are not. |
|
|
2110 | .IP "\s-1EV_STAT_ENABLE\s0" 4 |
|
|
2111 | .IX Item "EV_STAT_ENABLE" |
|
|
2112 | If undefined or defined to be \f(CW1\fR, then stat watchers are supported. If |
|
|
2113 | defined to be \f(CW0\fR, then they are not. |
|
|
2114 | .IP "\s-1EV_FORK_ENABLE\s0" 4 |
|
|
2115 | .IX Item "EV_FORK_ENABLE" |
|
|
2116 | If undefined or defined to be \f(CW1\fR, then fork watchers are supported. If |
|
|
2117 | defined to be \f(CW0\fR, then they are not. |
|
|
2118 | .IP "\s-1EV_MINIMAL\s0" 4 |
|
|
2119 | .IX Item "EV_MINIMAL" |
|
|
2120 | If you need to shave off some kilobytes of code at the expense of some |
|
|
2121 | speed, define this symbol to \f(CW1\fR. Currently only used for gcc to override |
|
|
2122 | some inlining decisions, saves roughly 30% codesize of amd64. |
|
|
2123 | .IP "\s-1EV_PID_HASHSIZE\s0" 4 |
|
|
2124 | .IX Item "EV_PID_HASHSIZE" |
|
|
2125 | \&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by |
|
|
2126 | pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_MINIMAL\*(C'\fR), usually more |
|
|
2127 | than enough. If you need to manage thousands of children you might want to |
|
|
2128 | increase this value. |
|
|
2129 | .IP "\s-1EV_COMMON\s0" 4 |
|
|
2130 | .IX Item "EV_COMMON" |
|
|
2131 | By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining |
|
|
2132 | this macro to a something else you can include more and other types of |
|
|
2133 | members. You have to define it each time you include one of the files, |
|
|
2134 | though, and it must be identical each time. |
|
|
2135 | .Sp |
|
|
2136 | For example, the perl \s-1EV\s0 module uses something like this: |
|
|
2137 | .Sp |
|
|
2138 | .Vb 3 |
|
|
2139 | \& #define EV_COMMON \e |
|
|
2140 | \& SV *self; /* contains this struct */ \e |
|
|
2141 | \& SV *cb_sv, *fh /* note no trailing ";" */ |
|
|
2142 | .Ve |
|
|
2143 | .IP "\s-1EV_CB_DECLARE\s0 (type)" 4 |
|
|
2144 | .IX Item "EV_CB_DECLARE (type)" |
|
|
2145 | .PD 0 |
|
|
2146 | .IP "\s-1EV_CB_INVOKE\s0 (watcher, revents)" 4 |
|
|
2147 | .IX Item "EV_CB_INVOKE (watcher, revents)" |
|
|
2148 | .IP "ev_set_cb (ev, cb)" 4 |
|
|
2149 | .IX Item "ev_set_cb (ev, cb)" |
|
|
2150 | .PD |
|
|
2151 | Can be used to change the callback member declaration in each watcher, |
|
|
2152 | and the way callbacks are invoked and set. Must expand to a struct member |
|
|
2153 | definition and a statement, respectively. See the \fIev.v\fR header file for |
|
|
2154 | their default definitions. One possible use for overriding these is to |
|
|
2155 | avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use |
|
|
2156 | method calls instead of plain function calls in \*(C+. |
|
|
2157 | .Sh "\s-1EXAMPLES\s0" |
|
|
2158 | .IX Subsection "EXAMPLES" |
|
|
2159 | For a real-world example of a program the includes libev |
|
|
2160 | verbatim, you can have a look at the \s-1EV\s0 perl module |
|
|
2161 | (<http://software.schmorp.de/pkg/EV.html>). It has the libev files in |
|
|
2162 | the \fIlibev/\fR subdirectory and includes them in the \fI\s-1EV/EVAPI\s0.h\fR (public |
|
|
2163 | interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file |
|
|
2164 | will be compiled. It is pretty complex because it provides its own header |
|
|
2165 | file. |
|
|
2166 | .Sp |
|
|
2167 | The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file |
|
|
2168 | that everybody includes and which overrides some autoconf choices: |
|
|
2169 | .Sp |
|
|
2170 | .Vb 4 |
|
|
2171 | \& #define EV_USE_POLL 0 |
|
|
2172 | \& #define EV_MULTIPLICITY 0 |
|
|
2173 | \& #define EV_PERIODICS 0 |
|
|
2174 | \& #define EV_CONFIG_H <config.h> |
|
|
2175 | .Ve |
|
|
2176 | .Sp |
|
|
2177 | .Vb 1 |
|
|
2178 | \& #include "ev++.h" |
|
|
2179 | .Ve |
|
|
2180 | .Sp |
|
|
2181 | And a \fIev_cpp.C\fR implementation file that contains libev proper and is compiled: |
|
|
2182 | .Sp |
|
|
2183 | .Vb 2 |
|
|
2184 | \& #include "ev_cpp.h" |
|
|
2185 | \& #include "ev.c" |
|
|
2186 | .Ve |
|
|
2187 | .SH "COMPLEXITIES" |
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2188 | .IX Header "COMPLEXITIES" |
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2189 | In this section the complexities of (many of) the algorithms used inside |
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2190 | libev will be explained. For complexity discussions about backends see the |
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2191 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
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2192 | .RS 4 |
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2193 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
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2194 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
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2195 | .PD 0 |
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2196 | .IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4 |
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2197 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
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2198 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
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2199 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
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2200 | .IP "Stopping check/prepare/idle watchers: O(1)" 4 |
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2201 | .IX Item "Stopping check/prepare/idle watchers: O(1)" |
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2202 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))" 4 |
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2203 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % 16))" |
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2204 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
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2205 | .IX Item "Finding the next timer per loop iteration: O(1)" |
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2206 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
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2207 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
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2208 | .IP "Activating one watcher: O(1)" 4 |
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2209 | .IX Item "Activating one watcher: O(1)" |
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2210 | .RE |
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2211 | .RS 4 |
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2212 | .PD |
1434 | .SH "AUTHOR" |
2213 | .SH "AUTHOR" |
1435 | .IX Header "AUTHOR" |
2214 | .IX Header "AUTHOR" |
1436 | Marc Lehmann <libev@schmorp.de>. |
2215 | Marc Lehmann <libev@schmorp.de>. |