… | |
… | |
131 | .\} |
131 | .\} |
132 | .rm #[ #] #H #V #F C |
132 | .rm #[ #] #H #V #F C |
133 | .\" ======================================================================== |
133 | .\" ======================================================================== |
134 | .\" |
134 | .\" |
135 | .IX Title "LIBEV 3" |
135 | .IX Title "LIBEV 3" |
136 | .TH LIBEV 3 "2019-12-20" "libev-4.27" "libev - high performance full featured event loop" |
136 | .TH LIBEV 3 "2021-01-11" "libev-4.33" "libev - high performance full featured event loop" |
137 | .\" For nroff, turn off justification. Always turn off hyphenation; it makes |
137 | .\" For nroff, turn off justification. Always turn off hyphenation; it makes |
138 | .\" way too many mistakes in technical documents. |
138 | .\" way too many mistakes in technical documents. |
139 | .if n .ad l |
139 | .if n .ad l |
140 | .nh |
140 | .nh |
141 | .SH "NAME" |
141 | .SH "NAME" |
… | |
… | |
593 | threads that are not interested in handling them. |
593 | threads that are not interested in handling them. |
594 | .Sp |
594 | .Sp |
595 | Signalfd will not be used by default as this changes your signal mask, and |
595 | Signalfd will not be used by default as this changes your signal mask, and |
596 | there are a lot of shoddy libraries and programs (glib's threadpool for |
596 | there are a lot of shoddy libraries and programs (glib's threadpool for |
597 | example) that can't properly initialise their signal masks. |
597 | example) that can't properly initialise their signal masks. |
|
|
598 | .ie n .IP """EVFLAG_NOSIGMASK""" 4 |
|
|
599 | .el .IP "\f(CWEVFLAG_NOSIGMASK\fR" 4 |
|
|
600 | .IX Item "EVFLAG_NOSIGMASK" |
|
|
601 | When this flag is specified, then libev will avoid to modify the signal |
|
|
602 | mask. Specifically, this means you have to make sure signals are unblocked |
|
|
603 | when you want to receive them. |
|
|
604 | .Sp |
|
|
605 | This behaviour is useful when you want to do your own signal handling, or |
|
|
606 | want to handle signals only in specific threads and want to avoid libev |
|
|
607 | unblocking the signals. |
|
|
608 | .Sp |
|
|
609 | It's also required by \s-1POSIX\s0 in a threaded program, as libev calls |
|
|
610 | \&\f(CW\*(C`sigprocmask\*(C'\fR, whose behaviour is officially unspecified. |
598 | .ie n .IP """EVFLAG_NOTIMERFD""" 4 |
611 | .ie n .IP """EVFLAG_NOTIMERFD""" 4 |
599 | .el .IP "\f(CWEVFLAG_NOTIMERFD\fR" 4 |
612 | .el .IP "\f(CWEVFLAG_NOTIMERFD\fR" 4 |
600 | .IX Item "EVFLAG_NOTIMERFD" |
613 | .IX Item "EVFLAG_NOTIMERFD" |
601 | When this flag is specified, the libev will avoid using a \f(CW\*(C`timerfd\*(C'\fR to |
614 | When this flag is specified, the libev will avoid using a \f(CW\*(C`timerfd\*(C'\fR to |
602 | detect time jumps. It will still be able to detect time jumps, but takes |
615 | detect time jumps. It will still be able to detect time jumps, but takes |
603 | longer and has a lower accuracy in doing so, but saves a file descriptor |
616 | longer and has a lower accuracy in doing so, but saves a file descriptor |
604 | per loop. |
617 | per loop. |
605 | .ie n .IP """EVFLAG_NOSIGMASK""" 4 |
|
|
606 | .el .IP "\f(CWEVFLAG_NOSIGMASK\fR" 4 |
|
|
607 | .IX Item "EVFLAG_NOSIGMASK" |
|
|
608 | When this flag is specified, then libev will avoid to modify the signal |
|
|
609 | mask. Specifically, this means you have to make sure signals are unblocked |
|
|
610 | when you want to receive them. |
|
|
611 | .Sp |
618 | .Sp |
612 | This behaviour is useful when you want to do your own signal handling, or |
619 | The current implementation only tries to use a \f(CW\*(C`timerfd\*(C'\fR when the first |
613 | want to handle signals only in specific threads and want to avoid libev |
620 | \&\f(CW\*(C`ev_periodic\*(C'\fR watcher is started and falls back on other methods if it |
614 | unblocking the signals. |
621 | cannot be created, but this behaviour might change in the future. |
615 | .Sp |
|
|
616 | It's also required by \s-1POSIX\s0 in a threaded program, as libev calls |
|
|
617 | \&\f(CW\*(C`sigprocmask\*(C'\fR, whose behaviour is officially unspecified. |
|
|
618 | .Sp |
|
|
619 | This flag's behaviour will become the default in future versions of libev. |
|
|
620 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
622 | .ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 |
621 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
623 | .el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 |
622 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
624 | .IX Item "EVBACKEND_SELECT (value 1, portable select backend)" |
623 | This is your standard \fBselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
625 | This is your standard \fBselect\fR\|(2) backend. Not \fIcompletely\fR standard, as |
624 | libev tries to roll its own fd_set with no limits on the number of fds, |
626 | libev tries to roll its own fd_set with no limits on the number of fds, |
… | |
… | |
1085 | \& \- Queue all expired timers. |
1087 | \& \- Queue all expired timers. |
1086 | \& \- Queue all expired periodics. |
1088 | \& \- Queue all expired periodics. |
1087 | \& \- Queue all idle watchers with priority higher than that of pending events. |
1089 | \& \- Queue all idle watchers with priority higher than that of pending events. |
1088 | \& \- Queue all check watchers. |
1090 | \& \- Queue all check watchers. |
1089 | \& \- Call all queued watchers in reverse order (i.e. check watchers first). |
1091 | \& \- Call all queued watchers in reverse order (i.e. check watchers first). |
1090 | \& Signals and child watchers are implemented as I/O watchers, and will |
1092 | \& Signals, async and child watchers are implemented as I/O watchers, and |
1091 | \& be handled here by queueing them when their watcher gets executed. |
1093 | \& will be handled here by queueing them when their watcher gets executed. |
1092 | \& \- If ev_break has been called, or EVRUN_ONCE or EVRUN_NOWAIT |
1094 | \& \- If ev_break has been called, or EVRUN_ONCE or EVRUN_NOWAIT |
1093 | \& were used, or there are no active watchers, goto FINISH, otherwise |
1095 | \& were used, or there are no active watchers, goto FINISH, otherwise |
1094 | \& continue with step LOOP. |
1096 | \& continue with step LOOP. |
1095 | \& FINISH: |
1097 | \& FINISH: |
1096 | \& \- Reset the ev_break status iff it was EVBREAK_ONE. |
1098 | \& \- Reset the ev_break status iff it was EVBREAK_ONE. |
… | |
… | |
1347 | with a watcher-specific start function (\f(CW\*(C`ev_TYPE_start (loop, watcher |
1349 | with a watcher-specific start function (\f(CW\*(C`ev_TYPE_start (loop, watcher |
1348 | *)\*(C'\fR), and you can stop watching for events at any time by calling the |
1350 | *)\*(C'\fR), and you can stop watching for events at any time by calling the |
1349 | corresponding stop function (\f(CW\*(C`ev_TYPE_stop (loop, watcher *)\*(C'\fR. |
1351 | corresponding stop function (\f(CW\*(C`ev_TYPE_stop (loop, watcher *)\*(C'\fR. |
1350 | .PP |
1352 | .PP |
1351 | As long as your watcher is active (has been started but not stopped) you |
1353 | As long as your watcher is active (has been started but not stopped) you |
1352 | must not touch the values stored in it. Most specifically you must never |
1354 | must not touch the values stored in it except when explicitly documented |
1353 | reinitialise it or call its \f(CW\*(C`ev_TYPE_set\*(C'\fR macro. |
1355 | otherwise. Most specifically you must never reinitialise it or call its |
|
|
1356 | \&\f(CW\*(C`ev_TYPE_set\*(C'\fR macro. |
1354 | .PP |
1357 | .PP |
1355 | Each and every callback receives the event loop pointer as first, the |
1358 | Each and every callback receives the event loop pointer as first, the |
1356 | registered watcher structure as second, and a bitset of received events as |
1359 | registered watcher structure as second, and a bitset of received events as |
1357 | third argument. |
1360 | third argument. |
1358 | .PP |
1361 | .PP |
… | |
… | |
1529 | therefore a good idea to always call its \f(CW\*(C`ev_TYPE_stop\*(C'\fR function. |
1532 | therefore a good idea to always call its \f(CW\*(C`ev_TYPE_stop\*(C'\fR function. |
1530 | .IP "bool ev_is_active (ev_TYPE *watcher)" 4 |
1533 | .IP "bool ev_is_active (ev_TYPE *watcher)" 4 |
1531 | .IX Item "bool ev_is_active (ev_TYPE *watcher)" |
1534 | .IX Item "bool ev_is_active (ev_TYPE *watcher)" |
1532 | Returns a true value iff the watcher is active (i.e. it has been started |
1535 | Returns a true value iff the watcher is active (i.e. it has been started |
1533 | and not yet been stopped). As long as a watcher is active you must not modify |
1536 | and not yet been stopped). As long as a watcher is active you must not modify |
1534 | it. |
1537 | it unless documented otherwise. |
1535 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
1538 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
1536 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
1539 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
1537 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
1540 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
1538 | events but its callback has not yet been invoked). As long as a watcher |
1541 | events but its callback has not yet been invoked). As long as a watcher |
1539 | is pending (but not active) you must not call an init function on it (but |
1542 | is pending (but not active) you must not call an init function on it (but |
… | |
… | |
1765 | .IX Header "WATCHER TYPES" |
1768 | .IX Header "WATCHER TYPES" |
1766 | This section describes each watcher in detail, but will not repeat |
1769 | This section describes each watcher in detail, but will not repeat |
1767 | information given in the last section. Any initialisation/set macros, |
1770 | information given in the last section. Any initialisation/set macros, |
1768 | functions and members specific to the watcher type are explained. |
1771 | functions and members specific to the watcher type are explained. |
1769 | .PP |
1772 | .PP |
1770 | Members are additionally marked with either \fI[read\-only]\fR, meaning that, |
1773 | Most members are additionally marked with either \fI[read\-only]\fR, meaning |
1771 | while the watcher is active, you can look at the member and expect some |
1774 | that, while the watcher is active, you can look at the member and expect |
1772 | sensible content, but you must not modify it (you can modify it while the |
1775 | some sensible content, but you must not modify it (you can modify it while |
1773 | watcher is stopped to your hearts content), or \fI[read\-write]\fR, which |
1776 | the watcher is stopped to your hearts content), or \fI[read\-write]\fR, which |
1774 | means you can expect it to have some sensible content while the watcher |
1777 | means you can expect it to have some sensible content while the watcher is |
1775 | is active, but you can also modify it. Modifying it may not do something |
1778 | active, but you can also modify it (within the same thread as the event |
|
|
1779 | loop, i.e. without creating data races). Modifying it may not do something |
1776 | sensible or take immediate effect (or do anything at all), but libev will |
1780 | sensible or take immediate effect (or do anything at all), but libev will |
1777 | not crash or malfunction in any way. |
1781 | not crash or malfunction in any way. |
|
|
1782 | .PP |
|
|
1783 | In any case, the documentation for each member will explain what the |
|
|
1784 | effects are, and if there are any additional access restrictions. |
1778 | .ie n .SS """ev_io"" \- is this file descriptor readable or writable?" |
1785 | .ie n .SS """ev_io"" \- is this file descriptor readable or writable?" |
1779 | .el .SS "\f(CWev_io\fP \- is this file descriptor readable or writable?" |
1786 | .el .SS "\f(CWev_io\fP \- is this file descriptor readable or writable?" |
1780 | .IX Subsection "ev_io - is this file descriptor readable or writable?" |
1787 | .IX Subsection "ev_io - is this file descriptor readable or writable?" |
1781 | I/O watchers check whether a file descriptor is readable or writable |
1788 | I/O watchers check whether a file descriptor is readable or writable |
1782 | in each iteration of the event loop, or, more precisely, when reading |
1789 | in each iteration of the event loop, or, more precisely, when reading |
… | |
… | |
1948 | .PD 0 |
1955 | .PD 0 |
1949 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
1956 | .IP "ev_io_set (ev_io *, int fd, int events)" 4 |
1950 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
1957 | .IX Item "ev_io_set (ev_io *, int fd, int events)" |
1951 | .PD |
1958 | .PD |
1952 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The \f(CW\*(C`fd\*(C'\fR is the file descriptor to |
1959 | Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The \f(CW\*(C`fd\*(C'\fR is the file descriptor to |
1953 | receive events for and \f(CW\*(C`events\*(C'\fR is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or |
1960 | receive events for and \f(CW\*(C`events\*(C'\fR is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR, both |
1954 | \&\f(CW\*(C`EV_READ | EV_WRITE\*(C'\fR, to express the desire to receive the given events. |
1961 | \&\f(CW\*(C`EV_READ | EV_WRITE\*(C'\fR or \f(CW0\fR, to express the desire to receive the given |
|
|
1962 | events. |
|
|
1963 | .Sp |
|
|
1964 | Note that setting the \f(CW\*(C`events\*(C'\fR to \f(CW0\fR and starting the watcher is |
|
|
1965 | supported, but not specially optimized \- if your program sometimes happens |
|
|
1966 | to generate this combination this is fine, but if it is easy to avoid |
|
|
1967 | starting an io watcher watching for no events you should do so. |
|
|
1968 | .IP "ev_io_modify (ev_io *, int events)" 4 |
|
|
1969 | .IX Item "ev_io_modify (ev_io *, int events)" |
|
|
1970 | Similar to \f(CW\*(C`ev_io_set\*(C'\fR, but only changes the requested events. Using this |
|
|
1971 | might be faster with some backends, as libev can assume that the \f(CW\*(C`fd\*(C'\fR |
|
|
1972 | still refers to the same underlying file description, something it cannot |
|
|
1973 | do when using \f(CW\*(C`ev_io_set\*(C'\fR. |
1955 | .IP "int fd [read\-only]" 4 |
1974 | .IP "int fd [no\-modify]" 4 |
1956 | .IX Item "int fd [read-only]" |
1975 | .IX Item "int fd [no-modify]" |
1957 | The file descriptor being watched. |
1976 | The file descriptor being watched. While it can be read at any time, you |
|
|
1977 | must not modify this member even when the watcher is stopped \- always use |
|
|
1978 | \&\f(CW\*(C`ev_io_set\*(C'\fR for that. |
1958 | .IP "int events [read\-only]" 4 |
1979 | .IP "int events [no\-modify]" 4 |
1959 | .IX Item "int events [read-only]" |
1980 | .IX Item "int events [no-modify]" |
1960 | The events being watched. |
1981 | The set of events the fd is being watched for, among other flags. Remember |
|
|
1982 | that this is a bit set \- to test for \f(CW\*(C`EV_READ\*(C'\fR, use \f(CW\*(C`w\->events & |
|
|
1983 | EV_READ\*(C'\fR, and similarly for \f(CW\*(C`EV_WRITE\*(C'\fR. |
|
|
1984 | .Sp |
|
|
1985 | As with \f(CW\*(C`fd\*(C'\fR, you must not modify this member even when the watcher is |
|
|
1986 | stopped, always use \f(CW\*(C`ev_io_set\*(C'\fR or \f(CW\*(C`ev_io_modify\*(C'\fR for that. |
1961 | .PP |
1987 | .PP |
1962 | \fIExamples\fR |
1988 | \fIExamples\fR |
1963 | .IX Subsection "Examples" |
1989 | .IX Subsection "Examples" |
1964 | .PP |
1990 | .PP |
1965 | Example: Call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
1991 | Example: Call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well |
… | |
… | |
3976 | .PP |
4002 | .PP |
3977 | First, you need to associate some data with the event loop: |
4003 | First, you need to associate some data with the event loop: |
3978 | .PP |
4004 | .PP |
3979 | .Vb 6 |
4005 | .Vb 6 |
3980 | \& typedef struct { |
4006 | \& typedef struct { |
3981 | \& mutex_t lock; /* global loop lock */ |
4007 | \& pthread_mutex_t lock; /* global loop lock */ |
|
|
4008 | \& pthread_t tid; |
|
|
4009 | \& pthread_cond_t invoke_cv; |
3982 | \& ev_async async_w; |
4010 | \& ev_async async_w; |
3983 | \& thread_t tid; |
|
|
3984 | \& cond_t invoke_cv; |
|
|
3985 | \& } userdata; |
4011 | \& } userdata; |
3986 | \& |
4012 | \& |
3987 | \& void prepare_loop (EV_P) |
4013 | \& void prepare_loop (EV_P) |
3988 | \& { |
4014 | \& { |
3989 | \& // for simplicity, we use a static userdata struct. |
4015 | \& // for simplicity, we use a static userdata struct. |
3990 | \& static userdata u; |
4016 | \& static userdata u; |
3991 | \& |
4017 | \& |
3992 | \& ev_async_init (&u\->async_w, async_cb); |
4018 | \& ev_async_init (&u.async_w, async_cb); |
3993 | \& ev_async_start (EV_A_ &u\->async_w); |
4019 | \& ev_async_start (EV_A_ &u.async_w); |
3994 | \& |
4020 | \& |
3995 | \& pthread_mutex_init (&u\->lock, 0); |
4021 | \& pthread_mutex_init (&u.lock, 0); |
3996 | \& pthread_cond_init (&u\->invoke_cv, 0); |
4022 | \& pthread_cond_init (&u.invoke_cv, 0); |
3997 | \& |
4023 | \& |
3998 | \& // now associate this with the loop |
4024 | \& // now associate this with the loop |
3999 | \& ev_set_userdata (EV_A_ u); |
4025 | \& ev_set_userdata (EV_A_ &u); |
4000 | \& ev_set_invoke_pending_cb (EV_A_ l_invoke); |
4026 | \& ev_set_invoke_pending_cb (EV_A_ l_invoke); |
4001 | \& ev_set_loop_release_cb (EV_A_ l_release, l_acquire); |
4027 | \& ev_set_loop_release_cb (EV_A_ l_release, l_acquire); |
4002 | \& |
4028 | \& |
4003 | \& // then create the thread running ev_run |
4029 | \& // then create the thread running ev_run |
4004 | \& pthread_create (&u\->tid, 0, l_run, EV_A); |
4030 | \& pthread_create (&u.tid, 0, l_run, EV_A); |
4005 | \& } |
4031 | \& } |
4006 | .Ve |
4032 | .Ve |
4007 | .PP |
4033 | .PP |
4008 | The callback for the \f(CW\*(C`ev_async\*(C'\fR watcher does nothing: the watcher is used |
4034 | The callback for the \f(CW\*(C`ev_async\*(C'\fR watcher does nothing: the watcher is used |
4009 | solely to wake up the event loop so it takes notice of any new watchers |
4035 | solely to wake up the event loop so it takes notice of any new watchers |
… | |
… | |
4393 | gets automatically stopped and restarted when reconfiguring it with this |
4419 | gets automatically stopped and restarted when reconfiguring it with this |
4394 | method. |
4420 | method. |
4395 | .Sp |
4421 | .Sp |
4396 | For \f(CW\*(C`ev::embed\*(C'\fR watchers this method is called \f(CW\*(C`set_embed\*(C'\fR, to avoid |
4422 | For \f(CW\*(C`ev::embed\*(C'\fR watchers this method is called \f(CW\*(C`set_embed\*(C'\fR, to avoid |
4397 | clashing with the \f(CW\*(C`set (loop)\*(C'\fR method. |
4423 | clashing with the \f(CW\*(C`set (loop)\*(C'\fR method. |
|
|
4424 | .Sp |
|
|
4425 | For \f(CW\*(C`ev::io\*(C'\fR watchers there is an additional \f(CW\*(C`set\*(C'\fR method that acepts a |
|
|
4426 | new event mask only, and internally calls \f(CW\*(C`ev_io_modfify\*(C'\fR. |
4398 | .IP "w\->start ()" 4 |
4427 | .IP "w\->start ()" 4 |
4399 | .IX Item "w->start ()" |
4428 | .IX Item "w->start ()" |
4400 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
4429 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
4401 | constructor already stores the event loop. |
4430 | constructor already stores the event loop. |
4402 | .IP "w\->start ([arguments])" 4 |
4431 | .IP "w\->start ([arguments])" 4 |