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Revision 1.117 by root, Fri Dec 20 20:51:46 2019 UTC vs.
Revision 1.119 by root, Wed Jan 22 02:00:13 2020 UTC

… …
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 "2020-01-22" "libev-4.31" "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"
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593threads that are not interested in handling them. 593threads that are not interested in handling them.
594.Sp 594.Sp
595Signalfd will not be used by default as this changes your signal mask, and 595Signalfd will not be used by default as this changes your signal mask, and
596there are a lot of shoddy libraries and programs (glib's threadpool for 596there are a lot of shoddy libraries and programs (glib's threadpool for
597example) that can't properly initialise their signal masks. 597example) 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"
601When this flag is specified, then libev will avoid to modify the signal
602mask. Specifically, this means you have to make sure signals are unblocked
603when you want to receive them.
604.Sp
605This behaviour is useful when you want to do your own signal handling, or
606want to handle signals only in specific threads and want to avoid libev
607unblocking the signals.
608.Sp
609It'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"
601When this flag is specified, the libev will avoid using a \f(CW\*(C`timerfd\*(C'\fR to 614When this flag is specified, the libev will avoid using a \f(CW\*(C`timerfd\*(C'\fR to
602detect time jumps. It will still be able to detect time jumps, but takes 615detect time jumps. It will still be able to detect time jumps, but takes
603longer and has a lower accuracy in doing so, but saves a file descriptor 616longer and has a lower accuracy in doing so, but saves a file descriptor
604per loop. 617per loop.
605.ie n .IP """EVFLAG_NOSIGMASK""" 4
606.el .IP "\f(CWEVFLAG_NOSIGMASK\fR" 4
607.IX Item "EVFLAG_NOSIGMASK"
608When this flag is specified, then libev will avoid to modify the signal
609mask. Specifically, this means you have to make sure signals are unblocked
610when you want to receive them.
611.Sp 618.Sp
612This behaviour is useful when you want to do your own signal handling, or 619The current implementation only tries to use a \f(CW\*(C`timerfd\*(C'\fR when the first
613want 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
614unblocking the signals. 621cannot be created, but this behaviour might change in the future.
615.Sp
616It'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
619This 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)"
623This is your standard \fBselect\fR\|(2) backend. Not \fIcompletely\fR standard, as 625This is your standard \fBselect\fR\|(2) backend. Not \fIcompletely\fR standard, as
624libev tries to roll its own fd_set with no limits on the number of fds, 626libev tries to roll its own fd_set with no limits on the number of fds,
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1765.IX Header "WATCHER TYPES" 1767.IX Header "WATCHER TYPES"
1766This section describes each watcher in detail, but will not repeat 1768This section describes each watcher in detail, but will not repeat
1767information given in the last section. Any initialisation/set macros, 1769information given in the last section. Any initialisation/set macros,
1768functions and members specific to the watcher type are explained. 1770functions and members specific to the watcher type are explained.
1769.PP 1771.PP
1770Members are additionally marked with either \fI[read\-only]\fR, meaning that, 1772Most members are additionally marked with either \fI[read\-only]\fR, meaning
1771while the watcher is active, you can look at the member and expect some 1773that, while the watcher is active, you can look at the member and expect
1772sensible content, but you must not modify it (you can modify it while the 1774some sensible content, but you must not modify it (you can modify it while
1773watcher is stopped to your hearts content), or \fI[read\-write]\fR, which 1775the watcher is stopped to your hearts content), or \fI[read\-write]\fR, which
1774means you can expect it to have some sensible content while the watcher 1776means you can expect it to have some sensible content while the watcher
1775is active, but you can also modify it. Modifying it may not do something 1777is active, but you can also modify it. Modifying it may not do something
1776sensible or take immediate effect (or do anything at all), but libev will 1778sensible or take immediate effect (or do anything at all), but libev will
1777not crash or malfunction in any way. 1779not crash or malfunction in any way.
1780.PP
1781In any case, the documentation for each member will explain what the
1782effects are, and if there are any additional access restrictions.
1778.ie n .SS """ev_io"" \- is this file descriptor readable or writable?" 1783.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?" 1784.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?" 1785.IX Subsection "ev_io - is this file descriptor readable or writable?"
1781I/O watchers check whether a file descriptor is readable or writable 1786I/O watchers check whether a file descriptor is readable or writable
1782in each iteration of the event loop, or, more precisely, when reading 1787in each iteration of the event loop, or, more precisely, when reading
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1950.IX Item "ev_io_set (ev_io *, int fd, int events)" 1955.IX Item "ev_io_set (ev_io *, int fd, int events)"
1951.PD 1956.PD
1952Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The \f(CW\*(C`fd\*(C'\fR is the file descriptor to 1957Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The \f(CW\*(C`fd\*(C'\fR is the file descriptor to
1953receive 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 1958receive 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
1954\&\f(CW\*(C`EV_READ | EV_WRITE\*(C'\fR, to express the desire to receive the given events. 1959\&\f(CW\*(C`EV_READ | EV_WRITE\*(C'\fR, to express the desire to receive the given events.
1960.IP "ev_io_modify (ev_io *, int events)" 4
1961.IX Item "ev_io_modify (ev_io *, int events)"
1962Similar to \f(CW\*(C`ev_io_set\*(C'\fR, but only changes the event mask. Using this might
1963be faster with some backends, as libev can assume that the \f(CW\*(C`fd\*(C'\fR still
1964refers to the same underlying file description, something it cannot do
1965when using \f(CW\*(C`ev_io_set\*(C'\fR.
1955.IP "int fd [read\-only]" 4 1966.IP "int fd [no\-modify]" 4
1956.IX Item "int fd [read-only]" 1967.IX Item "int fd [no-modify]"
1957The file descriptor being watched. 1968The file descriptor being watched. While it can be read at any time, you
1969must not modify this member even when the watcher is stopped \- always use
1970\&\f(CW\*(C`ev_io_set\*(C'\fR for that.
1958.IP "int events [read\-only]" 4 1971.IP "int events [no\-modify]" 4
1959.IX Item "int events [read-only]" 1972.IX Item "int events [no-modify]"
1960The events being watched. 1973The set of events being watched, among other flags. This field is a
1974bit set \- to test for \f(CW\*(C`EV_READ\*(C'\fR, use \f(CW\*(C`w\->events & EV_READ\*(C'\fR, and
1975similarly for \f(CW\*(C`EV_WRITE\*(C'\fR.
1976.Sp
1977As with \f(CW\*(C`fd\*(C'\fR, you must not modify this member even when the watcher is
1978stopped, always use \f(CW\*(C`ev_io_set\*(C'\fR or \f(CW\*(C`ev_io_modify\*(C'\fR for that.
1961.PP 1979.PP
1962\fIExamples\fR 1980\fIExamples\fR
1963.IX Subsection "Examples" 1981.IX Subsection "Examples"
1964.PP 1982.PP
1965Example: Call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well 1983Example: Call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well

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