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122.\} 131.\}
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124.\" ======================================================================== 133.\" ========================================================================
125.\" 134.\"
126.IX Title "LIBEV 3" 135.IX Title "LIBEV 3"
127.TH LIBEV 3 "2013-06-07" "libev-4.15" "libev - high performance full featured event loop" 136.TH LIBEV 3 "2013-10-29" "libev-4.15" "libev - high performance full featured event loop"
128.\" For nroff, turn off justification. Always turn off hyphenation; it makes 137.\" For nroff, turn off justification. Always turn off hyphenation; it makes
129.\" way too many mistakes in technical documents. 138.\" way too many mistakes in technical documents.
130.if n .ad l 139.if n .ad l
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132.SH "NAME" 141.SH "NAME"
… …
134.SH "SYNOPSIS" 143.SH "SYNOPSIS"
135.IX Header "SYNOPSIS" 144.IX Header "SYNOPSIS"
136.Vb 1 145.Vb 1
137\& #include <ev.h> 146\& #include <ev.h>
138.Ve 147.Ve
139.SS "\s-1EXAMPLE\s0 \s-1PROGRAM\s0" 148.SS "\s-1EXAMPLE PROGRAM\s0"
140.IX Subsection "EXAMPLE PROGRAM" 149.IX Subsection "EXAMPLE PROGRAM"
141.Vb 2 150.Vb 2
142\& // a single header file is required 151\& // a single header file is required
143\& #include <ev.h> 152\& #include <ev.h>
144\& 153\&
… …
212throughout this document. 221throughout this document.
213.SH "WHAT TO READ WHEN IN A HURRY" 222.SH "WHAT TO READ WHEN IN A HURRY"
214.IX Header "WHAT TO READ WHEN IN A HURRY" 223.IX Header "WHAT TO READ WHEN IN A HURRY"
215This manual tries to be very detailed, but unfortunately, this also makes 224This manual tries to be very detailed, but unfortunately, this also makes
216it very long. If you just want to know the basics of libev, I suggest 225it very long. If you just want to know the basics of libev, I suggest
217reading \*(L"\s-1ANATOMY\s0 \s-1OF\s0 A \s-1WATCHER\s0\*(R", then the \*(L"\s-1EXAMPLE\s0 \s-1PROGRAM\s0\*(R" above and 226reading \*(L"\s-1ANATOMY OF A WATCHER\*(R"\s0, then the \*(L"\s-1EXAMPLE PROGRAM\*(R"\s0 above and
218look up the missing functions in \*(L"\s-1GLOBAL\s0 \s-1FUNCTIONS\s0\*(R" and the \f(CW\*(C`ev_io\*(C'\fR and 227look up the missing functions in \*(L"\s-1GLOBAL FUNCTIONS\*(R"\s0 and the \f(CW\*(C`ev_io\*(C'\fR and
219\&\f(CW\*(C`ev_timer\*(C'\fR sections in \*(L"\s-1WATCHER\s0 \s-1TYPES\s0\*(R". 228\&\f(CW\*(C`ev_timer\*(C'\fR sections in \*(L"\s-1WATCHER TYPES\*(R"\s0.
220.SH "ABOUT LIBEV" 229.SH "ABOUT LIBEV"
221.IX Header "ABOUT LIBEV" 230.IX Header "ABOUT LIBEV"
222Libev is an event loop: you register interest in certain events (such as a 231Libev is an event loop: you register interest in certain events (such as a
223file descriptor being readable or a timeout occurring), and it will manage 232file descriptor being readable or a timeout occurring), and it will manage
224these event sources and provide your program with events. 233these event sources and provide your program with events.
… …
255more info about various configuration options please have a look at 264more info about various configuration options please have a look at
256\&\fB\s-1EMBED\s0\fR section in this manual. If libev was configured without support 265\&\fB\s-1EMBED\s0\fR section in this manual. If libev was configured without support
257for multiple event loops, then all functions taking an initial argument of 266for multiple event loops, then all functions taking an initial argument of
258name \f(CW\*(C`loop\*(C'\fR (which is always of type \f(CW\*(C`struct ev_loop *\*(C'\fR) will not have 267name \f(CW\*(C`loop\*(C'\fR (which is always of type \f(CW\*(C`struct ev_loop *\*(C'\fR) will not have
259this argument. 268this argument.
260.SS "\s-1TIME\s0 \s-1REPRESENTATION\s0" 269.SS "\s-1TIME REPRESENTATION\s0"
261.IX Subsection "TIME REPRESENTATION" 270.IX Subsection "TIME REPRESENTATION"
262Libev represents time as a single floating point number, representing 271Libev represents time as a single floating point number, representing
263the (fractional) number of seconds since the (\s-1POSIX\s0) epoch (in practice 272the (fractional) number of seconds since the (\s-1POSIX\s0) epoch (in practice
264somewhere near the beginning of 1970, details are complicated, don't 273somewhere near the beginning of 1970, details are complicated, don't
265ask). This type is called \f(CW\*(C`ev_tstamp\*(C'\fR, which is what you should use 274ask). This type is called \f(CW\*(C`ev_tstamp\*(C'\fR, which is what you should use
… …
574\&\f(CW\*(C`sigprocmask\*(C'\fR, whose behaviour is officially unspecified. 583\&\f(CW\*(C`sigprocmask\*(C'\fR, whose behaviour is officially unspecified.
575.Sp 584.Sp
576This flag's behaviour will become the default in future versions of libev. 585This flag's behaviour will become the default in future versions of libev.
577.ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4 586.ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4
578.el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4 587.el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4
579.IX Item "EVBACKEND_SELECT (value 1, portable select backend)" 588.IX Item "EVBACKEND_SELECT (value 1, portable select backend)"
580This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as 589This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as
581libev tries to roll its own fd_set with no limits on the number of fds, 590libev tries to roll its own fd_set with no limits on the number of fds,
582but if that fails, expect a fairly low limit on the number of fds when 591but if that fails, expect a fairly low limit on the number of fds when
583using this backend. It doesn't scale too well (O(highest_fd)), but its 592using this backend. It doesn't scale too well (O(highest_fd)), but its
584usually the fastest backend for a low number of (low-numbered :) fds. 593usually the fastest backend for a low number of (low-numbered :) fds.
… …
593This backend maps \f(CW\*(C`EV_READ\*(C'\fR to the \f(CW\*(C`readfds\*(C'\fR set and \f(CW\*(C`EV_WRITE\*(C'\fR to the 602This backend maps \f(CW\*(C`EV_READ\*(C'\fR to the \f(CW\*(C`readfds\*(C'\fR set and \f(CW\*(C`EV_WRITE\*(C'\fR to the
594\&\f(CW\*(C`writefds\*(C'\fR set (and to work around Microsoft Windows bugs, also onto the 603\&\f(CW\*(C`writefds\*(C'\fR set (and to work around Microsoft Windows bugs, also onto the
595\&\f(CW\*(C`exceptfds\*(C'\fR set on that platform). 604\&\f(CW\*(C`exceptfds\*(C'\fR set on that platform).
596.ie n .IP """EVBACKEND_POLL"" (value 2, poll backend, available everywhere except on windows)" 4 605.ie n .IP """EVBACKEND_POLL"" (value 2, poll backend, available everywhere except on windows)" 4
597.el .IP "\f(CWEVBACKEND_POLL\fR (value 2, poll backend, available everywhere except on windows)" 4 606.el .IP "\f(CWEVBACKEND_POLL\fR (value 2, poll backend, available everywhere except on windows)" 4
598.IX Item "EVBACKEND_POLL (value 2, poll backend, available everywhere except on windows)" 607.IX Item "EVBACKEND_POLL (value 2, poll backend, available everywhere except on windows)"
599And this is your standard \fIpoll\fR\|(2) backend. It's more complicated 608And this is your standard \fIpoll\fR\|(2) backend. It's more complicated
600than select, but handles sparse fds better and has no artificial 609than select, but handles sparse fds better and has no artificial
601limit on the number of fds you can use (except it will slow down 610limit on the number of fds you can use (except it will slow down
602considerably with a lot of inactive fds). It scales similarly to select, 611considerably with a lot of inactive fds). It scales similarly to select,
603i.e. O(total_fds). See the entry for \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR, above, for 612i.e. O(total_fds). See the entry for \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR, above, for
… …
605.Sp 614.Sp
606This backend maps \f(CW\*(C`EV_READ\*(C'\fR to \f(CW\*(C`POLLIN | POLLERR | POLLHUP\*(C'\fR, and 615This backend maps \f(CW\*(C`EV_READ\*(C'\fR to \f(CW\*(C`POLLIN | POLLERR | POLLHUP\*(C'\fR, and
607\&\f(CW\*(C`EV_WRITE\*(C'\fR to \f(CW\*(C`POLLOUT | POLLERR | POLLHUP\*(C'\fR. 616\&\f(CW\*(C`EV_WRITE\*(C'\fR to \f(CW\*(C`POLLOUT | POLLERR | POLLHUP\*(C'\fR.
608.ie n .IP """EVBACKEND_EPOLL"" (value 4, Linux)" 4 617.ie n .IP """EVBACKEND_EPOLL"" (value 4, Linux)" 4
609.el .IP "\f(CWEVBACKEND_EPOLL\fR (value 4, Linux)" 4 618.el .IP "\f(CWEVBACKEND_EPOLL\fR (value 4, Linux)" 4
610.IX Item "EVBACKEND_EPOLL (value 4, Linux)" 619.IX Item "EVBACKEND_EPOLL (value 4, Linux)"
611Use the linux-specific \fIepoll\fR\|(7) interface (for both pre\- and post\-2.6.9 620Use the linux-specific \fIepoll\fR\|(7) interface (for both pre\- and post\-2.6.9
612kernels). 621kernels).
613.Sp 622.Sp
614For few fds, this backend is a bit little slower than poll and select, but 623For few fds, this backend is a bit little slower than poll and select, but
615it scales phenomenally better. While poll and select usually scale like 624it scales phenomenally better. While poll and select usually scale like
… …
668.Sp 677.Sp
669This backend maps \f(CW\*(C`EV_READ\*(C'\fR and \f(CW\*(C`EV_WRITE\*(C'\fR in the same way as 678This backend maps \f(CW\*(C`EV_READ\*(C'\fR and \f(CW\*(C`EV_WRITE\*(C'\fR in the same way as
670\&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR. 679\&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR.
671.ie n .IP """EVBACKEND_KQUEUE"" (value 8, most \s-1BSD\s0 clones)" 4 680.ie n .IP """EVBACKEND_KQUEUE"" (value 8, most \s-1BSD\s0 clones)" 4
672.el .IP "\f(CWEVBACKEND_KQUEUE\fR (value 8, most \s-1BSD\s0 clones)" 4 681.el .IP "\f(CWEVBACKEND_KQUEUE\fR (value 8, most \s-1BSD\s0 clones)" 4
673.IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)" 682.IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)"
674Kqueue deserves special mention, as at the time of this writing, it 683Kqueue deserves special mention, as at the time of this writing, it
675was broken on all BSDs except NetBSD (usually it doesn't work reliably 684was broken on all BSDs except NetBSD (usually it doesn't work reliably
676with anything but sockets and pipes, except on Darwin, where of course 685with anything but sockets and pipes, except on Darwin, where of course
677it's completely useless). Unlike epoll, however, whose brokenness 686it's completely useless). Unlike epoll, however, whose brokenness
678is by design, these kqueue bugs can (and eventually will) be fixed 687is by design, these kqueue bugs can (and eventually will) be fixed
… …
698While nominally embeddable in other event loops, this doesn't work 707While nominally embeddable in other event loops, this doesn't work
699everywhere, so you might need to test for this. And since it is broken 708everywhere, so you might need to test for this. And since it is broken
700almost everywhere, you should only use it when you have a lot of sockets 709almost everywhere, you should only use it when you have a lot of sockets
701(for which it usually works), by embedding it into another event loop 710(for which it usually works), by embedding it into another event loop
702(e.g. \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR (but \f(CW\*(C`poll\*(C'\fR is of course 711(e.g. \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR (but \f(CW\*(C`poll\*(C'\fR is of course
703also broken on \s-1OS\s0 X)) and, did I mention it, using it only for sockets. 712also broken on \s-1OS X\s0)) and, did I mention it, using it only for sockets.
704.Sp 713.Sp
705This backend maps \f(CW\*(C`EV_READ\*(C'\fR into an \f(CW\*(C`EVFILT_READ\*(C'\fR kevent with 714This backend maps \f(CW\*(C`EV_READ\*(C'\fR into an \f(CW\*(C`EVFILT_READ\*(C'\fR kevent with
706\&\f(CW\*(C`NOTE_EOF\*(C'\fR, and \f(CW\*(C`EV_WRITE\*(C'\fR into an \f(CW\*(C`EVFILT_WRITE\*(C'\fR kevent with 715\&\f(CW\*(C`NOTE_EOF\*(C'\fR, and \f(CW\*(C`EV_WRITE\*(C'\fR into an \f(CW\*(C`EVFILT_WRITE\*(C'\fR kevent with
707\&\f(CW\*(C`NOTE_EOF\*(C'\fR. 716\&\f(CW\*(C`NOTE_EOF\*(C'\fR.
708.ie n .IP """EVBACKEND_DEVPOLL"" (value 16, Solaris 8)" 4 717.ie n .IP """EVBACKEND_DEVPOLL"" (value 16, Solaris 8)" 4
… …
712implementation). According to reports, \f(CW\*(C`/dev/poll\*(C'\fR only supports sockets 721implementation). According to reports, \f(CW\*(C`/dev/poll\*(C'\fR only supports sockets
713and is not embeddable, which would limit the usefulness of this backend 722and is not embeddable, which would limit the usefulness of this backend
714immensely. 723immensely.
715.ie n .IP """EVBACKEND_PORT"" (value 32, Solaris 10)" 4 724.ie n .IP """EVBACKEND_PORT"" (value 32, Solaris 10)" 4
716.el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4 725.el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4
717.IX Item "EVBACKEND_PORT (value 32, Solaris 10)" 726.IX Item "EVBACKEND_PORT (value 32, Solaris 10)"
718This uses the Solaris 10 event port mechanism. As with everything on Solaris, 727This uses the Solaris 10 event port mechanism. As with everything on Solaris,
719it's really slow, but it still scales very well (O(active_fds)). 728it's really slow, but it still scales very well (O(active_fds)).
720.Sp 729.Sp
721While this backend scales well, it requires one system call per active 730While this backend scales well, it requires one system call per active
722file descriptor per loop iteration. For small and medium numbers of file 731file descriptor per loop iteration. For small and medium numbers of file
… …
807reinitialise the kernel state for backends that have one. Despite the 816reinitialise the kernel state for backends that have one. Despite the
808name, you can call it anytime, but it makes most sense after forking, in 817name, you can call it anytime, but it makes most sense after forking, in
809the child process. You \fImust\fR call it (or use \f(CW\*(C`EVFLAG_FORKCHECK\*(C'\fR) in the 818the child process. You \fImust\fR call it (or use \f(CW\*(C`EVFLAG_FORKCHECK\*(C'\fR) in the
810child before resuming or calling \f(CW\*(C`ev_run\*(C'\fR. 819child before resuming or calling \f(CW\*(C`ev_run\*(C'\fR.
811.Sp 820.Sp
812Again, you \fIhave\fR to call it on \fIany\fR loop that you want to re-use after 821Again, you \fIhave\fR to call it on \fIany\fR loop that you want to re-use after
813a fork, \fIeven if you do not plan to use the loop in the parent\fR. This is 822a fork, \fIeven if you do not plan to use the loop in the parent\fR. This is
814because some kernel interfaces *cough* \fIkqueue\fR *cough* do funny things 823because some kernel interfaces *cough* \fIkqueue\fR *cough* do funny things
815during fork. 824during fork.
816.Sp 825.Sp
817On the other hand, you only need to call this function in the child 826On the other hand, you only need to call this function in the child
… …
1354example it might indicate that a fd is readable or writable, and if your 1363example it might indicate that a fd is readable or writable, and if your
1355callbacks is well-written it can just attempt the operation and cope with 1364callbacks is well-written it can just attempt the operation and cope with
1356the error from \fIread()\fR or \fIwrite()\fR. This will not work in multi-threaded 1365the error from \fIread()\fR or \fIwrite()\fR. This will not work in multi-threaded
1357programs, though, as the fd could already be closed and reused for another 1366programs, though, as the fd could already be closed and reused for another
1358thing, so beware. 1367thing, so beware.
1359.SS "\s-1GENERIC\s0 \s-1WATCHER\s0 \s-1FUNCTIONS\s0" 1368.SS "\s-1GENERIC WATCHER FUNCTIONS\s0"
1360.IX Subsection "GENERIC WATCHER FUNCTIONS" 1369.IX Subsection "GENERIC WATCHER FUNCTIONS"
1361.ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4 1370.ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4
1362.el .IP "\f(CWev_init\fR (ev_TYPE *watcher, callback)" 4 1371.el .IP "\f(CWev_init\fR (ev_TYPE *watcher, callback)" 4
1363.IX Item "ev_init (ev_TYPE *watcher, callback)" 1372.IX Item "ev_init (ev_TYPE *watcher, callback)"
1364This macro initialises the generic portion of a watcher. The contents 1373This macro initialises the generic portion of a watcher. The contents
… …
1472or might not have been clamped to the valid range. 1481or might not have been clamped to the valid range.
1473.Sp 1482.Sp
1474The default priority used by watchers when no priority has been set is 1483The default priority used by watchers when no priority has been set is
1475always \f(CW0\fR, which is supposed to not be too high and not be too low :). 1484always \f(CW0\fR, which is supposed to not be too high and not be too low :).
1476.Sp 1485.Sp
1477See \*(L"\s-1WATCHER\s0 \s-1PRIORITY\s0 \s-1MODELS\s0\*(R", below, for a more thorough treatment of 1486See \*(L"\s-1WATCHER PRIORITY MODELS\*(R"\s0, below, for a more thorough treatment of
1478priorities. 1487priorities.
1479.IP "ev_invoke (loop, ev_TYPE *watcher, int revents)" 4 1488.IP "ev_invoke (loop, ev_TYPE *watcher, int revents)" 4
1480.IX Item "ev_invoke (loop, ev_TYPE *watcher, int revents)" 1489.IX Item "ev_invoke (loop, ev_TYPE *watcher, int revents)"
1481Invoke the \f(CW\*(C`watcher\*(C'\fR with the given \f(CW\*(C`loop\*(C'\fR and \f(CW\*(C`revents\*(C'\fR. Neither 1490Invoke the \f(CW\*(C`watcher\*(C'\fR with the given \f(CW\*(C`loop\*(C'\fR and \f(CW\*(C`revents\*(C'\fR. Neither
1482\&\f(CW\*(C`loop\*(C'\fR nor \f(CW\*(C`revents\*(C'\fR need to be valid as long as the watcher callback 1491\&\f(CW\*(C`loop\*(C'\fR nor \f(CW\*(C`revents\*(C'\fR need to be valid as long as the watcher callback
… …
1502not started in the first place. 1511not started in the first place.
1503.Sp 1512.Sp
1504See also \f(CW\*(C`ev_feed_fd_event\*(C'\fR and \f(CW\*(C`ev_feed_signal_event\*(C'\fR for related 1513See also \f(CW\*(C`ev_feed_fd_event\*(C'\fR and \f(CW\*(C`ev_feed_signal_event\*(C'\fR for related
1505functions that do not need a watcher. 1514functions that do not need a watcher.
1506.PP 1515.PP
1507See also the \*(L"\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0\*(R" and \*(L"\s-1BUILDING\s0 \s-1YOUR\s0 1516See also the \*(L"\s-1ASSOCIATING CUSTOM DATA WITH A WATCHER\*(R"\s0 and \*(L"\s-1BUILDING YOUR
1508\&\s-1OWN\s0 \s-1COMPOSITE\s0 \s-1WATCHERS\s0\*(R" idioms. 1517OWN COMPOSITE WATCHERS\*(R"\s0 idioms.
1509.SS "\s-1WATCHER\s0 \s-1STATES\s0" 1518.SS "\s-1WATCHER STATES\s0"
1510.IX Subsection "WATCHER STATES" 1519.IX Subsection "WATCHER STATES"
1511There are various watcher states mentioned throughout this manual \- 1520There are various watcher states mentioned throughout this manual \-
1512active, pending and so on. In this section these states and the rules to 1521active, pending and so on. In this section these states and the rules to
1513transition between them will be described in more detail \- and while these 1522transition between them will be described in more detail \- and while these
1514rules might look complicated, they usually do \*(L"the right thing\*(R". 1523rules might look complicated, they usually do \*(L"the right thing\*(R".
… …
1557.Sp 1566.Sp
1558While stopped (and not pending) the watcher is essentially in the 1567While stopped (and not pending) the watcher is essentially in the
1559initialised state, that is, it can be reused, moved, modified in any way 1568initialised state, that is, it can be reused, moved, modified in any way
1560you wish (but when you trash the memory block, you need to \f(CW\*(C`ev_TYPE_init\*(C'\fR 1569you wish (but when you trash the memory block, you need to \f(CW\*(C`ev_TYPE_init\*(C'\fR
1561it again). 1570it again).
1562.SS "\s-1WATCHER\s0 \s-1PRIORITY\s0 \s-1MODELS\s0" 1571.SS "\s-1WATCHER PRIORITY MODELS\s0"
1563.IX Subsection "WATCHER PRIORITY MODELS" 1572.IX Subsection "WATCHER PRIORITY MODELS"
1564Many event loops support \fIwatcher priorities\fR, which are usually small 1573Many event loops support \fIwatcher priorities\fR, which are usually small
1565integers that influence the ordering of event callback invocation 1574integers that influence the ordering of event callback invocation
1566between watchers in some way, all else being equal. 1575between watchers in some way, all else being equal.
1567.PP 1576.PP
… …
1765wish to read \- you would first have to request some data. 1774wish to read \- you would first have to request some data.
1766.PP 1775.PP
1767Since files are typically not-so-well supported by advanced notification 1776Since files are typically not-so-well supported by advanced notification
1768mechanism, libev tries hard to emulate \s-1POSIX\s0 behaviour with respect 1777mechanism, libev tries hard to emulate \s-1POSIX\s0 behaviour with respect
1769to files, even though you should not use it. The reason for this is 1778to files, even though you should not use it. The reason for this is
1770convenience: sometimes you want to watch \s-1STDIN\s0 or \s-1STDOUT\s0, which is 1779convenience: sometimes you want to watch \s-1STDIN\s0 or \s-1STDOUT,\s0 which is
1771usually a tty, often a pipe, but also sometimes files or special devices 1780usually a tty, often a pipe, but also sometimes files or special devices
1772(for example, \f(CW\*(C`epoll\*(C'\fR on Linux works with \fI/dev/random\fR but not with 1781(for example, \f(CW\*(C`epoll\*(C'\fR on Linux works with \fI/dev/random\fR but not with
1773\&\fI/dev/urandom\fR), and even though the file might better be served with 1782\&\fI/dev/urandom\fR), and even though the file might better be served with
1774asynchronous I/O instead of with non-blocking I/O, it is still useful when 1783asynchronous I/O instead of with non-blocking I/O, it is still useful when
1775it \*(L"just works\*(R" instead of freezing. 1784it \*(L"just works\*(R" instead of freezing.
1776.PP 1785.PP
1777So avoid file descriptors pointing to files when you know it (e.g. use 1786So avoid file descriptors pointing to files when you know it (e.g. use
1778libeio), but use them when it is convenient, e.g. for \s-1STDIN/STDOUT\s0, or 1787libeio), but use them when it is convenient, e.g. for \s-1STDIN/STDOUT,\s0 or
1779when you rarely read from a file instead of from a socket, and want to 1788when you rarely read from a file instead of from a socket, and want to
1780reuse the same code path. 1789reuse the same code path.
1781.PP 1790.PP
1782\fIThe special problem of fork\fR 1791\fIThe special problem of fork\fR
1783.IX Subsection "The special problem of fork" 1792.IX Subsection "The special problem of fork"
… …
1793\fIThe special problem of \s-1SIGPIPE\s0\fR 1802\fIThe special problem of \s-1SIGPIPE\s0\fR
1794.IX Subsection "The special problem of SIGPIPE" 1803.IX Subsection "The special problem of SIGPIPE"
1795.PP 1804.PP
1796While not really specific to libev, it is easy to forget about \f(CW\*(C`SIGPIPE\*(C'\fR: 1805While not really specific to libev, it is easy to forget about \f(CW\*(C`SIGPIPE\*(C'\fR:
1797when writing to a pipe whose other end has been closed, your program gets 1806when writing to a pipe whose other end has been closed, your program gets
1798sent a \s-1SIGPIPE\s0, which, by default, aborts your program. For most programs 1807sent a \s-1SIGPIPE,\s0 which, by default, aborts your program. For most programs
1799this is sensible behaviour, for daemons, this is usually undesirable. 1808this is sensible behaviour, for daemons, this is usually undesirable.
1800.PP 1809.PP
1801So when you encounter spurious, unexplained daemon exits, make sure you 1810So when you encounter spurious, unexplained daemon exits, make sure you
1802ignore \s-1SIGPIPE\s0 (and maybe make sure you log the exit status of your daemon 1811ignore \s-1SIGPIPE \s0(and maybe make sure you log the exit status of your daemon
1803somewhere, as that would have given you a big clue). 1812somewhere, as that would have given you a big clue).
1804.PP 1813.PP
1805\fIThe special problem of \fIaccept()\fIing when you can't\fR 1814\fIThe special problem of \fIaccept()\fIing when you can't\fR
1806.IX Subsection "The special problem of accept()ing when you can't" 1815.IX Subsection "The special problem of accept()ing when you can't"
1807.PP 1816.PP
1808Many implementations of the \s-1POSIX\s0 \f(CW\*(C`accept\*(C'\fR function (for example, 1817Many implementations of the \s-1POSIX \s0\f(CW\*(C`accept\*(C'\fR function (for example,
1809found in post\-2004 Linux) have the peculiar behaviour of not removing a 1818found in post\-2004 Linux) have the peculiar behaviour of not removing a
1810connection from the pending queue in all error cases. 1819connection from the pending queue in all error cases.
1811.PP 1820.PP
1812For example, larger servers often run out of file descriptors (because 1821For example, larger servers often run out of file descriptors (because
1813of resource limits), causing \f(CW\*(C`accept\*(C'\fR to fail with \f(CW\*(C`ENFILE\*(C'\fR but not 1822of resource limits), causing \f(CW\*(C`accept\*(C'\fR to fail with \f(CW\*(C`ENFILE\*(C'\fR but not
… …
2418In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`offset\*(C'\fR are both being 2427In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`offset\*(C'\fR are both being
2419ignored. Instead, each time the periodic watcher gets scheduled, the 2428ignored. Instead, each time the periodic watcher gets scheduled, the
2420reschedule callback will be called with the watcher as first, and the 2429reschedule callback will be called with the watcher as first, and the
2421current time as second argument. 2430current time as second argument.
2422.Sp 2431.Sp
2423\&\s-1NOTE:\s0 \fIThis callback \s-1MUST\s0 \s-1NOT\s0 stop or destroy any periodic watcher, ever, 2432\&\s-1NOTE: \s0\fIThis callback \s-1MUST NOT\s0 stop or destroy any periodic watcher, ever,
2424or make \s-1ANY\s0 other event loop modifications whatsoever, unless explicitly 2433or make \s-1ANY\s0 other event loop modifications whatsoever, unless explicitly
2425allowed by documentation here\fR. 2434allowed by documentation here\fR.
2426.Sp 2435.Sp
2427If you need to stop it, return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop 2436If you need to stop it, return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop
2428it afterwards (e.g. by starting an \f(CW\*(C`ev_prepare\*(C'\fR watcher, which is the 2437it afterwards (e.g. by starting an \f(CW\*(C`ev_prepare\*(C'\fR watcher, which is the
… …
2442It must return the next time to trigger, based on the passed time value 2451It must return the next time to trigger, based on the passed time value
2443(that is, the lowest time value larger than to the second argument). It 2452(that is, the lowest time value larger than to the second argument). It
2444will usually be called just before the callback will be triggered, but 2453will usually be called just before the callback will be triggered, but
2445might be called at other times, too. 2454might be called at other times, too.
2446.Sp 2455.Sp
2447\&\s-1NOTE:\s0 \fIThis callback must always return a time that is higher than or 2456\&\s-1NOTE: \s0\fIThis callback must always return a time that is higher than or
2448equal to the passed \f(CI\*(C`now\*(C'\fI value\fR. 2457equal to the passed \f(CI\*(C`now\*(C'\fI value\fR.
2449.Sp 2458.Sp
2450This can be used to create very complex timers, such as a timer that 2459This can be used to create very complex timers, such as a timer that
2451triggers on \*(L"next midnight, local time\*(R". To do this, you would calculate the 2460triggers on \*(L"next midnight, local time\*(R". To do this, you would calculate the
2452next midnight after \f(CW\*(C`now\*(C'\fR and return the timestamp value for this. How 2461next midnight after \f(CW\*(C`now\*(C'\fR and return the timestamp value for this. How
… …
2577The simplest way to ensure that the signal mask is reset in the child is 2586The simplest way to ensure that the signal mask is reset in the child is
2578to install a fork handler with \f(CW\*(C`pthread_atfork\*(C'\fR that resets it. That will 2587to install a fork handler with \f(CW\*(C`pthread_atfork\*(C'\fR that resets it. That will
2579catch fork calls done by libraries (such as the libc) as well. 2588catch fork calls done by libraries (such as the libc) as well.
2580.PP 2589.PP
2581In current versions of libev, the signal will not be blocked indefinitely 2590In current versions of libev, the signal will not be blocked indefinitely
2582unless you use the \f(CW\*(C`signalfd\*(C'\fR \s-1API\s0 (\f(CW\*(C`EV_SIGNALFD\*(C'\fR). While this reduces 2591unless you use the \f(CW\*(C`signalfd\*(C'\fR \s-1API \s0(\f(CW\*(C`EV_SIGNALFD\*(C'\fR). While this reduces
2583the window of opportunity for problems, it will not go away, as libev 2592the window of opportunity for problems, it will not go away, as libev
2584\&\fIhas\fR to modify the signal mask, at least temporarily. 2593\&\fIhas\fR to modify the signal mask, at least temporarily.
2585.PP 2594.PP
2586So I can't stress this enough: \fIIf you do not reset your signal mask when 2595So I can't stress this enough: \fIIf you do not reset your signal mask when
2587you expect it to be empty, you have a race condition in your code\fR. This 2596you expect it to be empty, you have a race condition in your code\fR. This
… …
2617The signal the watcher watches out for. 2626The signal the watcher watches out for.
2618.PP 2627.PP
2619\fIExamples\fR 2628\fIExamples\fR
2620.IX Subsection "Examples" 2629.IX Subsection "Examples"
2621.PP 2630.PP
2622Example: Try to exit cleanly on \s-1SIGINT\s0. 2631Example: Try to exit cleanly on \s-1SIGINT.\s0
2623.PP 2632.PP
2624.Vb 5 2633.Vb 5
2625\& static void 2634\& static void
2626\& sigint_cb (struct ev_loop *loop, ev_signal *w, int revents) 2635\& sigint_cb (struct ev_loop *loop, ev_signal *w, int revents)
2627\& { 2636\& {
… …
2784compilation environment, which means that on systems with large file 2793compilation environment, which means that on systems with large file
2785support disabled by default, you get the 32 bit version of the stat 2794support disabled by default, you get the 32 bit version of the stat
2786structure. When using the library from programs that change the \s-1ABI\s0 to 2795structure. When using the library from programs that change the \s-1ABI\s0 to
2787use 64 bit file offsets the programs will fail. In that case you have to 2796use 64 bit file offsets the programs will fail. In that case you have to
2788compile libev with the same flags to get binary compatibility. This is 2797compile libev with the same flags to get binary compatibility. This is
2789obviously the case with any flags that change the \s-1ABI\s0, but the problem is 2798obviously the case with any flags that change the \s-1ABI,\s0 but the problem is
2790most noticeably displayed with ev_stat and large file support. 2799most noticeably displayed with ev_stat and large file support.
2791.PP 2800.PP
2792The solution for this is to lobby your distribution maker to make large 2801The solution for this is to lobby your distribution maker to make large
2793file interfaces available by default (as e.g. FreeBSD does) and not 2802file interfaces available by default (as e.g. FreeBSD does) and not
2794optional. Libev cannot simply switch on large file support because it has 2803optional. Libev cannot simply switch on large file support because it has
… …
3225.Ve 3234.Ve
3226.PP 3235.PP
3227Method 4: Do not use a prepare or check watcher because the module you 3236Method 4: Do not use a prepare or check watcher because the module you
3228want to embed is not flexible enough to support it. Instead, you can 3237want to embed is not flexible enough to support it. Instead, you can
3229override their poll function. The drawback with this solution is that the 3238override their poll function. The drawback with this solution is that the
3230main loop is now no longer controllable by \s-1EV\s0. The \f(CW\*(C`Glib::EV\*(C'\fR module uses 3239main loop is now no longer controllable by \s-1EV.\s0 The \f(CW\*(C`Glib::EV\*(C'\fR module uses
3231this approach, effectively embedding \s-1EV\s0 as a client into the horrible 3240this approach, effectively embedding \s-1EV\s0 as a client into the horrible
3232libglib event loop. 3241libglib event loop.
3233.PP 3242.PP
3234.Vb 4 3243.Vb 4
3235\& static gint 3244\& static gint
… …
3652\&\f(CW\*(C`EV_ERROR\*(C'\fR, \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or \f(CW\*(C`EV_TIMER\*(C'\fR) and the \f(CW\*(C`arg\*(C'\fR 3661\&\f(CW\*(C`EV_ERROR\*(C'\fR, \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or \f(CW\*(C`EV_TIMER\*(C'\fR) and the \f(CW\*(C`arg\*(C'\fR
3653value passed to \f(CW\*(C`ev_once\*(C'\fR. Note that it is possible to receive \fIboth\fR 3662value passed to \f(CW\*(C`ev_once\*(C'\fR. Note that it is possible to receive \fIboth\fR
3654a timeout and an io event at the same time \- you probably should give io 3663a timeout and an io event at the same time \- you probably should give io
3655events precedence. 3664events precedence.
3656.Sp 3665.Sp
3657Example: wait up to ten seconds for data to appear on \s-1STDIN_FILENO\s0. 3666Example: wait up to ten seconds for data to appear on \s-1STDIN_FILENO.\s0
3658.Sp 3667.Sp
3659.Vb 7 3668.Vb 7
3660\& static void stdin_ready (int revents, void *arg) 3669\& static void stdin_ready (int revents, void *arg)
3661\& { 3670\& {
3662\& if (revents & EV_READ) 3671\& if (revents & EV_READ)
… …
3678.SH "COMMON OR USEFUL IDIOMS (OR BOTH)" 3687.SH "COMMON OR USEFUL IDIOMS (OR BOTH)"
3679.IX Header "COMMON OR USEFUL IDIOMS (OR BOTH)" 3688.IX Header "COMMON OR USEFUL IDIOMS (OR BOTH)"
3680This section explains some common idioms that are not immediately 3689This section explains some common idioms that are not immediately
3681obvious. Note that examples are sprinkled over the whole manual, and this 3690obvious. Note that examples are sprinkled over the whole manual, and this
3682section only contains stuff that wouldn't fit anywhere else. 3691section only contains stuff that wouldn't fit anywhere else.
3683.SS "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" 3692.SS "\s-1ASSOCIATING CUSTOM DATA WITH A WATCHER\s0"
3684.IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" 3693.IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER"
3685Each watcher has, by default, a \f(CW\*(C`void *data\*(C'\fR member that you can read 3694Each watcher has, by default, a \f(CW\*(C`void *data\*(C'\fR member that you can read
3686or modify at any time: libev will completely ignore it. This can be used 3695or modify at any time: libev will completely ignore it. This can be used
3687to associate arbitrary data with your watcher. If you need more data and 3696to associate arbitrary data with your watcher. If you need more data and
3688don't want to allocate memory separately and store a pointer to it in that 3697don't want to allocate memory separately and store a pointer to it in that
… …
3714\& } 3723\& }
3715.Ve 3724.Ve
3716.PP 3725.PP
3717More interesting and less C\-conformant ways of casting your callback 3726More interesting and less C\-conformant ways of casting your callback
3718function type instead have been omitted. 3727function type instead have been omitted.
3719.SS "\s-1BUILDING\s0 \s-1YOUR\s0 \s-1OWN\s0 \s-1COMPOSITE\s0 \s-1WATCHERS\s0" 3728.SS "\s-1BUILDING YOUR OWN COMPOSITE WATCHERS\s0"
3720.IX Subsection "BUILDING YOUR OWN COMPOSITE WATCHERS" 3729.IX Subsection "BUILDING YOUR OWN COMPOSITE WATCHERS"
3721Another common scenario is to use some data structure with multiple 3730Another common scenario is to use some data structure with multiple
3722embedded watchers, in effect creating your own watcher that combines 3731embedded watchers, in effect creating your own watcher that combines
3723multiple libev event sources into one \*(L"super-watcher\*(R": 3732multiple libev event sources into one \*(L"super-watcher\*(R":
3724.PP 3733.PP
… …
3752\& { 3761\& {
3753\& struct my_biggy big = (struct my_biggy *) 3762\& struct my_biggy big = (struct my_biggy *)
3754\& (((char *)w) \- offsetof (struct my_biggy, t2)); 3763\& (((char *)w) \- offsetof (struct my_biggy, t2));
3755\& } 3764\& }
3756.Ve 3765.Ve
3757.SS "\s-1AVOIDING\s0 \s-1FINISHING\s0 \s-1BEFORE\s0 \s-1RETURNING\s0" 3766.SS "\s-1AVOIDING FINISHING BEFORE RETURNING\s0"
3758.IX Subsection "AVOIDING FINISHING BEFORE RETURNING" 3767.IX Subsection "AVOIDING FINISHING BEFORE RETURNING"
3759Often you have structures like this in event-based programs: 3768Often you have structures like this in event-based programs:
3760.PP 3769.PP
3761.Vb 4 3770.Vb 4
3762\& callback () 3771\& callback ()
… …
3795\& ev_feed_event (EV_A_ watcher, 0); 3804\& ev_feed_event (EV_A_ watcher, 0);
3796.Ve 3805.Ve
3797.PP 3806.PP
3798This way, \f(CW\*(C`start_new_request\*(C'\fR can safely return before the callback is 3807This way, \f(CW\*(C`start_new_request\*(C'\fR can safely return before the callback is
3799invoked, while not delaying callback invocation too much. 3808invoked, while not delaying callback invocation too much.
3800.SS "\s-1MODEL/NESTED\s0 \s-1EVENT\s0 \s-1LOOP\s0 \s-1INVOCATIONS\s0 \s-1AND\s0 \s-1EXIT\s0 \s-1CONDITIONS\s0" 3809.SS "\s-1MODEL/NESTED EVENT LOOP INVOCATIONS AND EXIT CONDITIONS\s0"
3801.IX Subsection "MODEL/NESTED EVENT LOOP INVOCATIONS AND EXIT CONDITIONS" 3810.IX Subsection "MODEL/NESTED EVENT LOOP INVOCATIONS AND EXIT CONDITIONS"
3802Often (especially in \s-1GUI\s0 toolkits) there are places where you have 3811Often (especially in \s-1GUI\s0 toolkits) there are places where you have
3803\&\fImodal\fR interaction, which is most easily implemented by recursively 3812\&\fImodal\fR interaction, which is most easily implemented by recursively
3804invoking \f(CW\*(C`ev_run\*(C'\fR. 3813invoking \f(CW\*(C`ev_run\*(C'\fR.
3805.PP 3814.PP
… …
3837\& exit_main_loop = 1; 3846\& exit_main_loop = 1;
3838\& 3847\&
3839\& // exit both 3848\& // exit both
3840\& exit_main_loop = exit_nested_loop = 1; 3849\& exit_main_loop = exit_nested_loop = 1;
3841.Ve 3850.Ve
3842.SS "\s-1THREAD\s0 \s-1LOCKING\s0 \s-1EXAMPLE\s0" 3851.SS "\s-1THREAD LOCKING EXAMPLE\s0"
3843.IX Subsection "THREAD LOCKING EXAMPLE" 3852.IX Subsection "THREAD LOCKING EXAMPLE"
3844Here is a fictitious example of how to run an event loop in a different 3853Here is a fictitious example of how to run an event loop in a different
3845thread from where callbacks are being invoked and watchers are 3854thread from where callbacks are being invoked and watchers are
3846created/added/removed. 3855created/added/removed.
3847.PP 3856.PP
… …
3988.PP 3997.PP
3989Note that sending the \f(CW\*(C`ev_async\*(C'\fR watcher is required because otherwise 3998Note that sending the \f(CW\*(C`ev_async\*(C'\fR watcher is required because otherwise
3990an event loop currently blocking in the kernel will have no knowledge 3999an event loop currently blocking in the kernel will have no knowledge
3991about the newly added timer. By waking up the loop it will pick up any new 4000about the newly added timer. By waking up the loop it will pick up any new
3992watchers in the next event loop iteration. 4001watchers in the next event loop iteration.
3993.SS "\s-1THREADS\s0, \s-1COROUTINES\s0, \s-1CONTINUATIONS\s0, \s-1QUEUES\s0... \s-1INSTEAD\s0 \s-1OF\s0 \s-1CALLBACKS\s0" 4002.SS "\s-1THREADS, COROUTINES, CONTINUATIONS, QUEUES... INSTEAD OF CALLBACKS\s0"
3994.IX Subsection "THREADS, COROUTINES, CONTINUATIONS, QUEUES... INSTEAD OF CALLBACKS" 4003.IX Subsection "THREADS, COROUTINES, CONTINUATIONS, QUEUES... INSTEAD OF CALLBACKS"
3995While the overhead of a callback that e.g. schedules a thread is small, it 4004While the overhead of a callback that e.g. schedules a thread is small, it
3996is still an overhead. If you embed libev, and your main usage is with some 4005is still an overhead. If you embed libev, and your main usage is with some
3997kind of threads or coroutines, you might want to customise libev so that 4006kind of threads or coroutines, you might want to customise libev so that
3998doesn't need callbacks anymore. 4007doesn't need callbacks anymore.
… …
4034You can do similar tricks if you have, say, threads with an event queue \- 4043You can do similar tricks if you have, say, threads with an event queue \-
4035instead of storing a coroutine, you store the queue object and instead of 4044instead of storing a coroutine, you store the queue object and instead of
4036switching to a coroutine, you push the watcher onto the queue and notify 4045switching to a coroutine, you push the watcher onto the queue and notify
4037any waiters. 4046any waiters.
4038.PP 4047.PP
4039To embed libev, see \*(L"\s-1EMBEDDING\s0\*(R", but in short, it's easiest to create two 4048To embed libev, see \*(L"\s-1EMBEDDING\*(R"\s0, but in short, it's easiest to create two
4040files, \fImy_ev.h\fR and \fImy_ev.c\fR that include the respective libev files: 4049files, \fImy_ev.h\fR and \fImy_ev.c\fR that include the respective libev files:
4041.PP 4050.PP
4042.Vb 4 4051.Vb 4
4043\& // my_ev.h 4052\& // my_ev.h
4044\& #define EV_CB_DECLARE(type) struct my_coro *cb; 4053\& #define EV_CB_DECLARE(type) struct my_coro *cb;
… …
4339there are additional modules that implement libev-compatible interfaces 4348there are additional modules that implement libev-compatible interfaces
4340to \f(CW\*(C`libadns\*(C'\fR (\f(CW\*(C`EV::ADNS\*(C'\fR, but \f(CW\*(C`AnyEvent::DNS\*(C'\fR is preferred nowadays), 4349to \f(CW\*(C`libadns\*(C'\fR (\f(CW\*(C`EV::ADNS\*(C'\fR, but \f(CW\*(C`AnyEvent::DNS\*(C'\fR is preferred nowadays),
4341\&\f(CW\*(C`Net::SNMP\*(C'\fR (\f(CW\*(C`Net::SNMP::EV\*(C'\fR) and the \f(CW\*(C`libglib\*(C'\fR event core (\f(CW\*(C`Glib::EV\*(C'\fR 4350\&\f(CW\*(C`Net::SNMP\*(C'\fR (\f(CW\*(C`Net::SNMP::EV\*(C'\fR) and the \f(CW\*(C`libglib\*(C'\fR event core (\f(CW\*(C`Glib::EV\*(C'\fR
4342and \f(CW\*(C`EV::Glib\*(C'\fR). 4351and \f(CW\*(C`EV::Glib\*(C'\fR).
4343.Sp 4352.Sp
4344It can be found and installed via \s-1CPAN\s0, its homepage is at 4353It can be found and installed via \s-1CPAN,\s0 its homepage is at
4345<http://software.schmorp.de/pkg/EV>. 4354<http://software.schmorp.de/pkg/EV>.
4346.IP "Python" 4 4355.IP "Python" 4
4347.IX Item "Python" 4356.IX Item "Python"
4348Python bindings can be found at <http://code.google.com/p/pyev/>. It 4357Python bindings can be found at <http://code.google.com/p/pyev/>. It
4349seems to be quite complete and well-documented. 4358seems to be quite complete and well-documented.
… …
4357Roger Pack reports that using the link order \f(CW\*(C`\-lws2_32 \-lmsvcrt\-ruby\-190\*(C'\fR 4366Roger Pack reports that using the link order \f(CW\*(C`\-lws2_32 \-lmsvcrt\-ruby\-190\*(C'\fR
4358makes rev work even on mingw. 4367makes rev work even on mingw.
4359.IP "Haskell" 4 4368.IP "Haskell" 4
4360.IX Item "Haskell" 4369.IX Item "Haskell"
4361A haskell binding to libev is available at 4370A haskell binding to libev is available at
4362http://hackage.haskell.org/cgi\-bin/hackage\-scripts/package/hlibev <http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hlibev>. 4371<http://hackage.haskell.org/cgi\-bin/hackage\-scripts/package/hlibev>.
4363.IP "D" 4 4372.IP "D" 4
4364.IX Item "D" 4373.IX Item "D"
4365Leandro Lucarella has written a D language binding (\fIev.d\fR) for libev, to 4374Leandro Lucarella has written a D language binding (\fIev.d\fR) for libev, to
4366be found at <http://www.llucax.com.ar/proj/ev.d/index.html>. 4375be found at <http://www.llucax.com.ar/proj/ev.d/index.html>.
4367.IP "Ocaml" 4 4376.IP "Ocaml" 4
4368.IX Item "Ocaml" 4377.IX Item "Ocaml"
4369Erkki Seppala has written Ocaml bindings for libev, to be found at 4378Erkki Seppala has written Ocaml bindings for libev, to be found at
4370http://modeemi.cs.tut.fi/~flux/software/ocaml\-ev/ <http://modeemi.cs.tut.fi/~flux/software/ocaml-ev/>. 4379<http://modeemi.cs.tut.fi/~flux/software/ocaml\-ev/>.
4371.IP "Lua" 4 4380.IP "Lua" 4
4372.IX Item "Lua" 4381.IX Item "Lua"
4373Brian Maher has written a partial interface to libev for lua (at the 4382Brian Maher has written a partial interface to libev for lua (at the
4374time of this writing, only \f(CW\*(C`ev_io\*(C'\fR and \f(CW\*(C`ev_timer\*(C'\fR), to be found at 4383time of this writing, only \f(CW\*(C`ev_io\*(C'\fR and \f(CW\*(C`ev_timer\*(C'\fR), to be found at
4375http://github.com/brimworks/lua\-ev <http://github.com/brimworks/lua-ev>. 4384<http://github.com/brimworks/lua\-ev>.
4376.IP "Javascript" 4 4385.IP "Javascript" 4
4377.IX Item "Javascript" 4386.IX Item "Javascript"
4378Node.js (<http://nodejs.org>) uses libev as the underlying event library. 4387Node.js (<http://nodejs.org>) uses libev as the underlying event library.
4379.IP "Others" 4 4388.IP "Others" 4
4380.IX Item "Others" 4389.IX Item "Others"
… …
4469.SS "\s-1FILESETS\s0" 4478.SS "\s-1FILESETS\s0"
4470.IX Subsection "FILESETS" 4479.IX Subsection "FILESETS"
4471Depending on what features you need you need to include one or more sets of files 4480Depending on what features you need you need to include one or more sets of files
4472in your application. 4481in your application.
4473.PP 4482.PP
4474\fI\s-1CORE\s0 \s-1EVENT\s0 \s-1LOOP\s0\fR 4483\fI\s-1CORE EVENT LOOP\s0\fR
4475.IX Subsection "CORE EVENT LOOP" 4484.IX Subsection "CORE EVENT LOOP"
4476.PP 4485.PP
4477To include only the libev core (all the \f(CW\*(C`ev_*\*(C'\fR functions), with manual 4486To include only the libev core (all the \f(CW\*(C`ev_*\*(C'\fR functions), with manual
4478configuration (no autoconf): 4487configuration (no autoconf):
4479.PP 4488.PP
… …
4482\& #include "ev.c" 4491\& #include "ev.c"
4483.Ve 4492.Ve
4484.PP 4493.PP
4485This will automatically include \fIev.h\fR, too, and should be done in a 4494This will automatically include \fIev.h\fR, too, and should be done in a
4486single C source file only to provide the function implementations. To use 4495single C source file only to provide the function implementations. To use
4487it, do the same for \fIev.h\fR in all files wishing to use this \s-1API\s0 (best 4496it, do the same for \fIev.h\fR in all files wishing to use this \s-1API \s0(best
4488done by writing a wrapper around \fIev.h\fR that you can include instead and 4497done by writing a wrapper around \fIev.h\fR that you can include instead and
4489where you can put other configuration options): 4498where you can put other configuration options):
4490.PP 4499.PP
4491.Vb 2 4500.Vb 2
4492\& #define EV_STANDALONE 1 4501\& #define EV_STANDALONE 1
… …
4516.Ve 4525.Ve
4517.PP 4526.PP
4518\&\fIev.c\fR includes the backend files directly when enabled, so you only need 4527\&\fIev.c\fR includes the backend files directly when enabled, so you only need
4519to compile this single file. 4528to compile this single file.
4520.PP 4529.PP
4521\fI\s-1LIBEVENT\s0 \s-1COMPATIBILITY\s0 \s-1API\s0\fR 4530\fI\s-1LIBEVENT COMPATIBILITY API\s0\fR
4522.IX Subsection "LIBEVENT COMPATIBILITY API" 4531.IX Subsection "LIBEVENT COMPATIBILITY API"
4523.PP 4532.PP
4524To include the libevent compatibility \s-1API\s0, also include: 4533To include the libevent compatibility \s-1API,\s0 also include:
4525.PP 4534.PP
4526.Vb 1 4535.Vb 1
4527\& #include "event.c" 4536\& #include "event.c"
4528.Ve 4537.Ve
4529.PP 4538.PP
… …
4531.PP 4540.PP
4532.Vb 1 4541.Vb 1
4533\& #include "event.h" 4542\& #include "event.h"
4534.Ve 4543.Ve
4535.PP 4544.PP
4536in the files that want to use the libevent \s-1API\s0. This also includes \fIev.h\fR. 4545in the files that want to use the libevent \s-1API.\s0 This also includes \fIev.h\fR.
4537.PP 4546.PP
4538You need the following additional files for this: 4547You need the following additional files for this:
4539.PP 4548.PP
4540.Vb 2 4549.Vb 2
4541\& event.h 4550\& event.h
4542\& event.c 4551\& event.c
4543.Ve 4552.Ve
4544.PP 4553.PP
4545\fI\s-1AUTOCONF\s0 \s-1SUPPORT\s0\fR 4554\fI\s-1AUTOCONF SUPPORT\s0\fR
4546.IX Subsection "AUTOCONF SUPPORT" 4555.IX Subsection "AUTOCONF SUPPORT"
4547.PP 4556.PP
4548Instead of using \f(CW\*(C`EV_STANDALONE=1\*(C'\fR and providing your configuration in 4557Instead of using \f(CW\*(C`EV_STANDALONE=1\*(C'\fR and providing your configuration in
4549whatever way you want, you can also \f(CW\*(C`m4_include([libev.m4])\*(C'\fR in your 4558whatever way you want, you can also \f(CW\*(C`m4_include([libev.m4])\*(C'\fR in your
4550\&\fIconfigure.ac\fR and leave \f(CW\*(C`EV_STANDALONE\*(C'\fR undefined. \fIev.c\fR will then 4559\&\fIconfigure.ac\fR and leave \f(CW\*(C`EV_STANDALONE\*(C'\fR undefined. \fIev.c\fR will then
… …
4553For this of course you need the m4 file: 4562For this of course you need the m4 file:
4554.PP 4563.PP
4555.Vb 1 4564.Vb 1
4556\& libev.m4 4565\& libev.m4
4557.Ve 4566.Ve
4558.SS "\s-1PREPROCESSOR\s0 \s-1SYMBOLS/MACROS\s0" 4567.SS "\s-1PREPROCESSOR SYMBOLS/MACROS\s0"
4559.IX Subsection "PREPROCESSOR SYMBOLS/MACROS" 4568.IX Subsection "PREPROCESSOR SYMBOLS/MACROS"
4560Libev can be configured via a variety of preprocessor symbols you have to 4569Libev can be configured via a variety of preprocessor symbols you have to
4561define before including (or compiling) any of its files. The default in 4570define before including (or compiling) any of its files. The default in
4562the absence of autoconf is documented for every option. 4571the absence of autoconf is documented for every option.
4563.PP 4572.PP
4564Symbols marked with \*(L"(h)\*(R" do not change the \s-1ABI\s0, and can have different 4573Symbols marked with \*(L"(h)\*(R" do not change the \s-1ABI,\s0 and can have different
4565values when compiling libev vs. including \fIev.h\fR, so it is permissible 4574values when compiling libev vs. including \fIev.h\fR, so it is permissible
4566to redefine them before including \fIev.h\fR without breaking compatibility 4575to redefine them before including \fIev.h\fR without breaking compatibility
4567to a compiled library. All other symbols change the \s-1ABI\s0, which means all 4576to a compiled library. All other symbols change the \s-1ABI,\s0 which means all
4568users of libev and the libev code itself must be compiled with compatible 4577users of libev and the libev code itself must be compiled with compatible
4569settings. 4578settings.
4570.IP "\s-1EV_COMPAT3\s0 (h)" 4 4579.IP "\s-1EV_COMPAT3 \s0(h)" 4
4571.IX Item "EV_COMPAT3 (h)" 4580.IX Item "EV_COMPAT3 (h)"
4572Backwards compatibility is a major concern for libev. This is why this 4581Backwards compatibility is a major concern for libev. This is why this
4573release of libev comes with wrappers for the functions and symbols that 4582release of libev comes with wrappers for the functions and symbols that
4574have been renamed between libev version 3 and 4. 4583have been renamed between libev version 3 and 4.
4575.Sp 4584.Sp
… …
4580typedef in that case. 4589typedef in that case.
4581.Sp 4590.Sp
4582In some future version, the default for \f(CW\*(C`EV_COMPAT3\*(C'\fR will become \f(CW0\fR, 4591In some future version, the default for \f(CW\*(C`EV_COMPAT3\*(C'\fR will become \f(CW0\fR,
4583and in some even more future version the compatibility code will be 4592and in some even more future version the compatibility code will be
4584removed completely. 4593removed completely.
4585.IP "\s-1EV_STANDALONE\s0 (h)" 4 4594.IP "\s-1EV_STANDALONE \s0(h)" 4
4586.IX Item "EV_STANDALONE (h)" 4595.IX Item "EV_STANDALONE (h)"
4587Must always be \f(CW1\fR if you do not use autoconf configuration, which 4596Must always be \f(CW1\fR if you do not use autoconf configuration, which
4588keeps libev from including \fIconfig.h\fR, and it also defines dummy 4597keeps libev from including \fIconfig.h\fR, and it also defines dummy
4589implementations for some libevent functions (such as logging, which is not 4598implementations for some libevent functions (such as logging, which is not
4590supported). It will also not define any of the structs usually found in 4599supported). It will also not define any of the structs usually found in
… …
4748handler \*(L"locking\*(R" as well as for signal and thread safety in \f(CW\*(C`ev_async\*(C'\fR 4757handler \*(L"locking\*(R" as well as for signal and thread safety in \f(CW\*(C`ev_async\*(C'\fR
4749watchers. 4758watchers.
4750.Sp 4759.Sp
4751In the absence of this define, libev will use \f(CW\*(C`sig_atomic_t volatile\*(C'\fR 4760In the absence of this define, libev will use \f(CW\*(C`sig_atomic_t volatile\*(C'\fR
4752(from \fIsignal.h\fR), which is usually good enough on most platforms. 4761(from \fIsignal.h\fR), which is usually good enough on most platforms.
4753.IP "\s-1EV_H\s0 (h)" 4 4762.IP "\s-1EV_H \s0(h)" 4
4754.IX Item "EV_H (h)" 4763.IX Item "EV_H (h)"
4755The name of the \fIev.h\fR header file used to include it. The default if 4764The name of the \fIev.h\fR header file used to include it. The default if
4756undefined is \f(CW"ev.h"\fR in \fIevent.h\fR, \fIev.c\fR and \fIev++.h\fR. This can be 4765undefined is \f(CW"ev.h"\fR in \fIevent.h\fR, \fIev.c\fR and \fIev++.h\fR. This can be
4757used to virtually rename the \fIev.h\fR header file in case of conflicts. 4766used to virtually rename the \fIev.h\fR header file in case of conflicts.
4758.IP "\s-1EV_CONFIG_H\s0 (h)" 4 4767.IP "\s-1EV_CONFIG_H \s0(h)" 4
4759.IX Item "EV_CONFIG_H (h)" 4768.IX Item "EV_CONFIG_H (h)"
4760If \f(CW\*(C`EV_STANDALONE\*(C'\fR isn't \f(CW1\fR, this variable can be used to override 4769If \f(CW\*(C`EV_STANDALONE\*(C'\fR isn't \f(CW1\fR, this variable can be used to override
4761\&\fIev.c\fR's idea of where to find the \fIconfig.h\fR file, similarly to 4770\&\fIev.c\fR's idea of where to find the \fIconfig.h\fR file, similarly to
4762\&\f(CW\*(C`EV_H\*(C'\fR, above. 4771\&\f(CW\*(C`EV_H\*(C'\fR, above.
4763.IP "\s-1EV_EVENT_H\s0 (h)" 4 4772.IP "\s-1EV_EVENT_H \s0(h)" 4
4764.IX Item "EV_EVENT_H (h)" 4773.IX Item "EV_EVENT_H (h)"
4765Similarly to \f(CW\*(C`EV_H\*(C'\fR, this macro can be used to override \fIevent.c\fR's idea 4774Similarly to \f(CW\*(C`EV_H\*(C'\fR, this macro can be used to override \fIevent.c\fR's idea
4766of how the \fIevent.h\fR header can be found, the default is \f(CW"event.h"\fR. 4775of how the \fIevent.h\fR header can be found, the default is \f(CW"event.h"\fR.
4767.IP "\s-1EV_PROTOTYPES\s0 (h)" 4 4776.IP "\s-1EV_PROTOTYPES \s0(h)" 4
4768.IX Item "EV_PROTOTYPES (h)" 4777.IX Item "EV_PROTOTYPES (h)"
4769If defined to be \f(CW0\fR, then \fIev.h\fR will not define any function 4778If defined to be \f(CW0\fR, then \fIev.h\fR will not define any function
4770prototypes, but still define all the structs and other symbols. This is 4779prototypes, but still define all the structs and other symbols. This is
4771occasionally useful if you want to provide your own wrapper functions 4780occasionally useful if you want to provide your own wrapper functions
4772around libev functions. 4781around libev functions.
… …
4796all the priorities, so having many of them (hundreds) uses a lot of space 4805all the priorities, so having many of them (hundreds) uses a lot of space
4797and time, so using the defaults of five priorities (\-2 .. +2) is usually 4806and time, so using the defaults of five priorities (\-2 .. +2) is usually
4798fine. 4807fine.
4799.Sp 4808.Sp
4800If your embedding application does not need any priorities, defining these 4809If your embedding application does not need any priorities, defining these
4801both to \f(CW0\fR will save some memory and \s-1CPU\s0. 4810both to \f(CW0\fR will save some memory and \s-1CPU.\s0
4802.IP "\s-1EV_PERIODIC_ENABLE\s0, \s-1EV_IDLE_ENABLE\s0, \s-1EV_EMBED_ENABLE\s0, \s-1EV_STAT_ENABLE\s0, \s-1EV_PREPARE_ENABLE\s0, \s-1EV_CHECK_ENABLE\s0, \s-1EV_FORK_ENABLE\s0, \s-1EV_SIGNAL_ENABLE\s0, \s-1EV_ASYNC_ENABLE\s0, \s-1EV_CHILD_ENABLE\s0." 4 4811.IP "\s-1EV_PERIODIC_ENABLE, EV_IDLE_ENABLE, EV_EMBED_ENABLE, EV_STAT_ENABLE, EV_PREPARE_ENABLE, EV_CHECK_ENABLE, EV_FORK_ENABLE, EV_SIGNAL_ENABLE, EV_ASYNC_ENABLE, EV_CHILD_ENABLE.\s0" 4
4803.IX Item "EV_PERIODIC_ENABLE, EV_IDLE_ENABLE, EV_EMBED_ENABLE, EV_STAT_ENABLE, EV_PREPARE_ENABLE, EV_CHECK_ENABLE, EV_FORK_ENABLE, EV_SIGNAL_ENABLE, EV_ASYNC_ENABLE, EV_CHILD_ENABLE." 4812.IX Item "EV_PERIODIC_ENABLE, EV_IDLE_ENABLE, EV_EMBED_ENABLE, EV_STAT_ENABLE, EV_PREPARE_ENABLE, EV_CHECK_ENABLE, EV_FORK_ENABLE, EV_SIGNAL_ENABLE, EV_ASYNC_ENABLE, EV_CHILD_ENABLE."
4804If undefined or defined to be \f(CW1\fR (and the platform supports it), then 4813If undefined or defined to be \f(CW1\fR (and the platform supports it), then
4805the respective watcher type is supported. If defined to be \f(CW0\fR, then it 4814the respective watcher type is supported. If defined to be \f(CW0\fR, then it
4806is not. Disabling watcher types mainly saves code size. 4815is not. Disabling watcher types mainly saves code size.
4807.IP "\s-1EV_FEATURES\s0" 4 4816.IP "\s-1EV_FEATURES\s0" 4
… …
4981.Vb 3 4990.Vb 3
4982\& #define EV_COMMON \e 4991\& #define EV_COMMON \e
4983\& SV *self; /* contains this struct */ \e 4992\& SV *self; /* contains this struct */ \e
4984\& SV *cb_sv, *fh /* note no trailing ";" */ 4993\& SV *cb_sv, *fh /* note no trailing ";" */
4985.Ve 4994.Ve
4986.IP "\s-1EV_CB_DECLARE\s0 (type)" 4 4995.IP "\s-1EV_CB_DECLARE \s0(type)" 4
4987.IX Item "EV_CB_DECLARE (type)" 4996.IX Item "EV_CB_DECLARE (type)"
4988.PD 0 4997.PD 0
4989.IP "\s-1EV_CB_INVOKE\s0 (watcher, revents)" 4 4998.IP "\s-1EV_CB_INVOKE \s0(watcher, revents)" 4
4990.IX Item "EV_CB_INVOKE (watcher, revents)" 4999.IX Item "EV_CB_INVOKE (watcher, revents)"
4991.IP "ev_set_cb (ev, cb)" 4 5000.IP "ev_set_cb (ev, cb)" 4
4992.IX Item "ev_set_cb (ev, cb)" 5001.IX Item "ev_set_cb (ev, cb)"
4993.PD 5002.PD
4994Can be used to change the callback member declaration in each watcher, 5003Can be used to change the callback member declaration in each watcher,
4995and the way callbacks are invoked and set. Must expand to a struct member 5004and the way callbacks are invoked and set. Must expand to a struct member
4996definition and a statement, respectively. See the \fIev.h\fR header file for 5005definition and a statement, respectively. See the \fIev.h\fR header file for
4997their default definitions. One possible use for overriding these is to 5006their default definitions. One possible use for overriding these is to
4998avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use 5007avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use
4999method calls instead of plain function calls in \*(C+. 5008method calls instead of plain function calls in \*(C+.
5000.SS "\s-1EXPORTED\s0 \s-1API\s0 \s-1SYMBOLS\s0" 5009.SS "\s-1EXPORTED API SYMBOLS\s0"
5001.IX Subsection "EXPORTED API SYMBOLS" 5010.IX Subsection "EXPORTED API SYMBOLS"
5002If you need to re-export the \s-1API\s0 (e.g. via a \s-1DLL\s0) and you need a list of 5011If you need to re-export the \s-1API \s0(e.g. via a \s-1DLL\s0) and you need a list of
5003exported symbols, you can use the provided \fISymbol.*\fR files which list 5012exported symbols, you can use the provided \fISymbol.*\fR files which list
5004all public symbols, one per line: 5013all public symbols, one per line:
5005.PP 5014.PP
5006.Vb 2 5015.Vb 2
5007\& Symbols.ev for libev proper 5016\& Symbols.ev for libev proper
… …
5059\& #include "ev_cpp.h" 5068\& #include "ev_cpp.h"
5060\& #include "ev.c" 5069\& #include "ev.c"
5061.Ve 5070.Ve
5062.SH "INTERACTION WITH OTHER PROGRAMS, LIBRARIES OR THE ENVIRONMENT" 5071.SH "INTERACTION WITH OTHER PROGRAMS, LIBRARIES OR THE ENVIRONMENT"
5063.IX Header "INTERACTION WITH OTHER PROGRAMS, LIBRARIES OR THE ENVIRONMENT" 5072.IX Header "INTERACTION WITH OTHER PROGRAMS, LIBRARIES OR THE ENVIRONMENT"
5064.SS "\s-1THREADS\s0 \s-1AND\s0 \s-1COROUTINES\s0" 5073.SS "\s-1THREADS AND COROUTINES\s0"
5065.IX Subsection "THREADS AND COROUTINES" 5074.IX Subsection "THREADS AND COROUTINES"
5066\fI\s-1THREADS\s0\fR 5075\fI\s-1THREADS\s0\fR
5067.IX Subsection "THREADS" 5076.IX Subsection "THREADS"
5068.PP 5077.PP
5069All libev functions are reentrant and thread-safe unless explicitly 5078All libev functions are reentrant and thread-safe unless explicitly
… …
5115An example use would be to communicate signals or other events that only 5124An example use would be to communicate signals or other events that only
5116work in the default loop by registering the signal watcher with the 5125work in the default loop by registering the signal watcher with the
5117default loop and triggering an \f(CW\*(C`ev_async\*(C'\fR watcher from the default loop 5126default loop and triggering an \f(CW\*(C`ev_async\*(C'\fR watcher from the default loop
5118watcher callback into the event loop interested in the signal. 5127watcher callback into the event loop interested in the signal.
5119.PP 5128.PP
5120See also \*(L"\s-1THREAD\s0 \s-1LOCKING\s0 \s-1EXAMPLE\s0\*(R". 5129See also \*(L"\s-1THREAD LOCKING EXAMPLE\*(R"\s0.
5121.PP 5130.PP
5122\fI\s-1COROUTINES\s0\fR 5131\fI\s-1COROUTINES\s0\fR
5123.IX Subsection "COROUTINES" 5132.IX Subsection "COROUTINES"
5124.PP 5133.PP
5125Libev is very accommodating to coroutines (\*(L"cooperative threads\*(R"): 5134Libev is very accommodating to coroutines (\*(L"cooperative threads\*(R"):
… …
5130that you must not do this from \f(CW\*(C`ev_periodic\*(C'\fR reschedule callbacks. 5139that you must not do this from \f(CW\*(C`ev_periodic\*(C'\fR reschedule callbacks.
5131.PP 5140.PP
5132Care has been taken to ensure that libev does not keep local state inside 5141Care has been taken to ensure that libev does not keep local state inside
5133\&\f(CW\*(C`ev_run\*(C'\fR, and other calls do not usually allow for coroutine switches as 5142\&\f(CW\*(C`ev_run\*(C'\fR, and other calls do not usually allow for coroutine switches as
5134they do not call any callbacks. 5143they do not call any callbacks.
5135.SS "\s-1COMPILER\s0 \s-1WARNINGS\s0" 5144.SS "\s-1COMPILER WARNINGS\s0"
5136.IX Subsection "COMPILER WARNINGS" 5145.IX Subsection "COMPILER WARNINGS"
5137Depending on your compiler and compiler settings, you might get no or a 5146Depending on your compiler and compiler settings, you might get no or a
5138lot of warnings when compiling libev code. Some people are apparently 5147lot of warnings when compiling libev code. Some people are apparently
5139scared by this. 5148scared by this.
5140.PP 5149.PP
… …
5192.PP 5201.PP
5193If you need, for some reason, empty reports from valgrind for your project 5202If you need, for some reason, empty reports from valgrind for your project
5194I suggest using suppression lists. 5203I suggest using suppression lists.
5195.SH "PORTABILITY NOTES" 5204.SH "PORTABILITY NOTES"
5196.IX Header "PORTABILITY NOTES" 5205.IX Header "PORTABILITY NOTES"
5197.SS "\s-1GNU/LINUX\s0 32 \s-1BIT\s0 \s-1LIMITATIONS\s0" 5206.SS "\s-1GNU/LINUX 32 BIT LIMITATIONS\s0"
5198.IX Subsection "GNU/LINUX 32 BIT LIMITATIONS" 5207.IX Subsection "GNU/LINUX 32 BIT LIMITATIONS"
5199GNU/Linux is the only common platform that supports 64 bit file/large file 5208GNU/Linux is the only common platform that supports 64 bit file/large file
5200interfaces but \fIdisables\fR them by default. 5209interfaces but \fIdisables\fR them by default.
5201.PP 5210.PP
5202That means that libev compiled in the default environment doesn't support 5211That means that libev compiled in the default environment doesn't support
5203files larger than 2GiB or so, which mainly affects \f(CW\*(C`ev_stat\*(C'\fR watchers. 5212files larger than 2GiB or so, which mainly affects \f(CW\*(C`ev_stat\*(C'\fR watchers.
5204.PP 5213.PP
5205Unfortunately, many programs try to work around this GNU/Linux issue 5214Unfortunately, many programs try to work around this GNU/Linux issue
5206by enabling the large file \s-1API\s0, which makes them incompatible with the 5215by enabling the large file \s-1API,\s0 which makes them incompatible with the
5207standard libev compiled for their system. 5216standard libev compiled for their system.
5208.PP 5217.PP
5209Likewise, libev cannot enable the large file \s-1API\s0 itself as this would 5218Likewise, libev cannot enable the large file \s-1API\s0 itself as this would
5210suddenly make it incompatible to the default compile time environment, 5219suddenly make it incompatible to the default compile time environment,
5211i.e. all programs not using special compile switches. 5220i.e. all programs not using special compile switches.
5212.SS "\s-1OS/X\s0 \s-1AND\s0 \s-1DARWIN\s0 \s-1BUGS\s0" 5221.SS "\s-1OS/X AND DARWIN BUGS\s0"
5213.IX Subsection "OS/X AND DARWIN BUGS" 5222.IX Subsection "OS/X AND DARWIN BUGS"
5214The whole thing is a bug if you ask me \- basically any system interface 5223The whole thing is a bug if you ask me \- basically any system interface
5215you touch is broken, whether it is locales, poll, kqueue or even the 5224you touch is broken, whether it is locales, poll, kqueue or even the
5216OpenGL drivers. 5225OpenGL drivers.
5217.PP 5226.PP
… …
5239.PP 5248.PP
5240\fI\f(CI\*(C`select\*(C'\fI is buggy\fR 5249\fI\f(CI\*(C`select\*(C'\fI is buggy\fR
5241.IX Subsection "select is buggy" 5250.IX Subsection "select is buggy"
5242.PP 5251.PP
5243All that's left is \f(CW\*(C`select\*(C'\fR, and of course Apple found a way to fuck this 5252All that's left is \f(CW\*(C`select\*(C'\fR, and of course Apple found a way to fuck this
5244one up as well: On \s-1OS/X\s0, \f(CW\*(C`select\*(C'\fR actively limits the number of file 5253one up as well: On \s-1OS/X, \s0\f(CW\*(C`select\*(C'\fR actively limits the number of file
5245descriptors you can pass in to 1024 \- your program suddenly crashes when 5254descriptors you can pass in to 1024 \- your program suddenly crashes when
5246you use more. 5255you use more.
5247.PP 5256.PP
5248There is an undocumented \*(L"workaround\*(R" for this \- defining 5257There is an undocumented \*(L"workaround\*(R" for this \- defining
5249\&\f(CW\*(C`_DARWIN_UNLIMITED_SELECT\*(C'\fR, which libev tries to use, so select \fIshould\fR 5258\&\f(CW\*(C`_DARWIN_UNLIMITED_SELECT\*(C'\fR, which libev tries to use, so select \fIshould\fR
5250work on \s-1OS/X\s0. 5259work on \s-1OS/X.\s0
5251.SS "\s-1SOLARIS\s0 \s-1PROBLEMS\s0 \s-1AND\s0 \s-1WORKAROUNDS\s0" 5260.SS "\s-1SOLARIS PROBLEMS AND WORKAROUNDS\s0"
5252.IX Subsection "SOLARIS PROBLEMS AND WORKAROUNDS" 5261.IX Subsection "SOLARIS PROBLEMS AND WORKAROUNDS"
5253\fI\f(CI\*(C`errno\*(C'\fI reentrancy\fR 5262\fI\f(CI\*(C`errno\*(C'\fI reentrancy\fR
5254.IX Subsection "errno reentrancy" 5263.IX Subsection "errno reentrancy"
5255.PP 5264.PP
5256The default compile environment on Solaris is unfortunately so 5265The default compile environment on Solaris is unfortunately so
… …
5273great. 5282great.
5274.PP 5283.PP
5275If you can't get it to work, you can try running the program by setting 5284If you can't get it to work, you can try running the program by setting
5276the environment variable \f(CW\*(C`LIBEV_FLAGS=3\*(C'\fR to only allow \f(CW\*(C`poll\*(C'\fR and 5285the environment variable \f(CW\*(C`LIBEV_FLAGS=3\*(C'\fR to only allow \f(CW\*(C`poll\*(C'\fR and
5277\&\f(CW\*(C`select\*(C'\fR backends. 5286\&\f(CW\*(C`select\*(C'\fR backends.
5278.SS "\s-1AIX\s0 \s-1POLL\s0 \s-1BUG\s0" 5287.SS "\s-1AIX POLL BUG\s0"
5279.IX Subsection "AIX POLL BUG" 5288.IX Subsection "AIX POLL BUG"
5280\&\s-1AIX\s0 unfortunately has a broken \f(CW\*(C`poll.h\*(C'\fR header. Libev works around 5289\&\s-1AIX\s0 unfortunately has a broken \f(CW\*(C`poll.h\*(C'\fR header. Libev works around
5281this by trying to avoid the poll backend altogether (i.e. it's not even 5290this by trying to avoid the poll backend altogether (i.e. it's not even
5282compiled in), which normally isn't a big problem as \f(CW\*(C`select\*(C'\fR works fine 5291compiled in), which normally isn't a big problem as \f(CW\*(C`select\*(C'\fR works fine
5283with large bitsets on \s-1AIX\s0, and \s-1AIX\s0 is dead anyway. 5292with large bitsets on \s-1AIX,\s0 and \s-1AIX\s0 is dead anyway.
5284.SS "\s-1WIN32\s0 \s-1PLATFORM\s0 \s-1LIMITATIONS\s0 \s-1AND\s0 \s-1WORKAROUNDS\s0" 5293.SS "\s-1WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS\s0"
5285.IX Subsection "WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS" 5294.IX Subsection "WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS"
5286\fIGeneral issues\fR 5295\fIGeneral issues\fR
5287.IX Subsection "General issues" 5296.IX Subsection "General issues"
5288.PP 5297.PP
5289Win32 doesn't support any of the standards (e.g. \s-1POSIX\s0) that libev 5298Win32 doesn't support any of the standards (e.g. \s-1POSIX\s0) that libev
… …
5358\& #define EV_USE_SELECT 1 5367\& #define EV_USE_SELECT 1
5359\& #define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */ 5368\& #define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */
5360.Ve 5369.Ve
5361.PP 5370.PP
5362Note that winsockets handling of fd sets is O(n), so you can easily get a 5371Note that winsockets handling of fd sets is O(n), so you can easily get a
5363complexity in the O(nA\*^X) range when using win32. 5372complexity in the O(nX) range when using win32.
5364.PP 5373.PP
5365\fILimited number of file descriptors\fR 5374\fILimited number of file descriptors\fR
5366.IX Subsection "Limited number of file descriptors" 5375.IX Subsection "Limited number of file descriptors"
5367.PP 5376.PP
5368Windows has numerous arbitrary (and low) limits on things. 5377Windows has numerous arbitrary (and low) limits on things.
… …
5384by calling \f(CW\*(C`_setmaxstdio\*(C'\fR, which can increase this limit to \f(CW2048\fR 5393by calling \f(CW\*(C`_setmaxstdio\*(C'\fR, which can increase this limit to \f(CW2048\fR
5385(another arbitrary limit), but is broken in many versions of the Microsoft 5394(another arbitrary limit), but is broken in many versions of the Microsoft
5386runtime libraries. This might get you to about \f(CW512\fR or \f(CW2048\fR sockets 5395runtime libraries. This might get you to about \f(CW512\fR or \f(CW2048\fR sockets
5387(depending on windows version and/or the phase of the moon). To get more, 5396(depending on windows version and/or the phase of the moon). To get more,
5388you need to wrap all I/O functions and provide your own fd management, but 5397you need to wrap all I/O functions and provide your own fd management, but
5389the cost of calling select (O(nA\*^X)) will likely make this unworkable. 5398the cost of calling select (O(nX)) will likely make this unworkable.
5390.SS "\s-1PORTABILITY\s0 \s-1REQUIREMENTS\s0" 5399.SS "\s-1PORTABILITY REQUIREMENTS\s0"
5391.IX Subsection "PORTABILITY REQUIREMENTS" 5400.IX Subsection "PORTABILITY REQUIREMENTS"
5392In addition to a working ISO-C implementation and of course the 5401In addition to a working ISO-C implementation and of course the
5393backend-specific APIs, libev relies on a few additional extensions: 5402backend-specific APIs, libev relies on a few additional extensions:
5394.ie n .IP """void (*)(ev_watcher_type *, int revents)"" must have compatible calling conventions regardless of ""ev_watcher_type *""." 4 5403.ie n .IP """void (*)(ev_watcher_type *, int revents)"" must have compatible calling conventions regardless of ""ev_watcher_type *""." 4
5395.el .IP "\f(CWvoid (*)(ev_watcher_type *, int revents)\fR must have compatible calling conventions regardless of \f(CWev_watcher_type *\fR." 4 5404.el .IP "\f(CWvoid (*)(ev_watcher_type *, int revents)\fR must have compatible calling conventions regardless of \f(CWev_watcher_type *\fR." 4
5396.IX Item "void (*)(ev_watcher_type *, int revents) must have compatible calling conventions regardless of ev_watcher_type *." 5405.IX Item "void (*)(ev_watcher_type *, int revents) must have compatible calling conventions regardless of ev_watcher_type *."
5397Libev assumes not only that all watcher pointers have the same internal 5406Libev assumes not only that all watcher pointers have the same internal
5398structure (guaranteed by \s-1POSIX\s0 but not by \s-1ISO\s0 C for example), but it also 5407structure (guaranteed by \s-1POSIX\s0 but not by \s-1ISO C\s0 for example), but it also
5399assumes that the same (machine) code can be used to call any watcher 5408assumes that the same (machine) code can be used to call any watcher
5400callback: The watcher callbacks have different type signatures, but libev 5409callback: The watcher callbacks have different type signatures, but libev
5401calls them using an \f(CW\*(C`ev_watcher *\*(C'\fR internally. 5410calls them using an \f(CW\*(C`ev_watcher *\*(C'\fR internally.
5402.IP "pointer accesses must be thread-atomic" 4 5411.IP "pointer accesses must be thread-atomic" 4
5403.IX Item "pointer accesses must be thread-atomic" 5412.IX Item "pointer accesses must be thread-atomic"
… …
5424except the initial one, and run the signal handling loop in the initial 5433except the initial one, and run the signal handling loop in the initial
5425thread as well. 5434thread as well.
5426.ie n .IP """long"" must be large enough for common memory allocation sizes" 4 5435.ie n .IP """long"" must be large enough for common memory allocation sizes" 4
5427.el .IP "\f(CWlong\fR must be large enough for common memory allocation sizes" 4 5436.el .IP "\f(CWlong\fR must be large enough for common memory allocation sizes" 4
5428.IX Item "long must be large enough for common memory allocation sizes" 5437.IX Item "long must be large enough for common memory allocation sizes"
5429To improve portability and simplify its \s-1API\s0, libev uses \f(CW\*(C`long\*(C'\fR internally 5438To improve portability and simplify its \s-1API,\s0 libev uses \f(CW\*(C`long\*(C'\fR internally
5430instead of \f(CW\*(C`size_t\*(C'\fR when allocating its data structures. On non-POSIX 5439instead of \f(CW\*(C`size_t\*(C'\fR when allocating its data structures. On non-POSIX
5431systems (Microsoft...) this might be unexpectedly low, but is still at 5440systems (Microsoft...) this might be unexpectedly low, but is still at
5432least 31 bits everywhere, which is enough for hundreds of millions of 5441least 31 bits everywhere, which is enough for hundreds of millions of
5433watchers. 5442watchers.
5434.ie n .IP """double"" must hold a time value in seconds with enough accuracy" 4 5443.ie n .IP """double"" must hold a time value in seconds with enough accuracy" 4
… …
5436.IX Item "double must hold a time value in seconds with enough accuracy" 5445.IX Item "double must hold a time value in seconds with enough accuracy"
5437The type \f(CW\*(C`double\*(C'\fR is used to represent timestamps. It is required to 5446The type \f(CW\*(C`double\*(C'\fR is used to represent timestamps. It is required to
5438have at least 51 bits of mantissa (and 9 bits of exponent), which is 5447have at least 51 bits of mantissa (and 9 bits of exponent), which is
5439good enough for at least into the year 4000 with millisecond accuracy 5448good enough for at least into the year 4000 with millisecond accuracy
5440(the design goal for libev). This requirement is overfulfilled by 5449(the design goal for libev). This requirement is overfulfilled by
5441implementations using \s-1IEEE\s0 754, which is basically all existing ones. 5450implementations using \s-1IEEE 754,\s0 which is basically all existing ones.
5442.Sp 5451.Sp
5443With \s-1IEEE\s0 754 doubles, you get microsecond accuracy until at least the 5452With \s-1IEEE 754\s0 doubles, you get microsecond accuracy until at least the
5444year 2255 (and millisecond accuracy till the year 287396 \- by then, libev 5453year 2255 (and millisecond accuracy till the year 287396 \- by then, libev
5445is either obsolete or somebody patched it to use \f(CW\*(C`long double\*(C'\fR or 5454is either obsolete or somebody patched it to use \f(CW\*(C`long double\*(C'\fR or
5446something like that, just kidding). 5455something like that, just kidding).
5447.PP 5456.PP
5448If you know of other additional requirements drop me a note. 5457If you know of other additional requirements drop me a note.
… …
5510calls in the current loop iteration and the loop is currently 5519calls in the current loop iteration and the loop is currently
5511blocked. Checking for async and signal events involves iterating over all 5520blocked. Checking for async and signal events involves iterating over all
5512running async watchers or all signal numbers. 5521running async watchers or all signal numbers.
5513.SH "PORTING FROM LIBEV 3.X TO 4.X" 5522.SH "PORTING FROM LIBEV 3.X TO 4.X"
5514.IX Header "PORTING FROM LIBEV 3.X TO 4.X" 5523.IX Header "PORTING FROM LIBEV 3.X TO 4.X"
5515The major version 4 introduced some incompatible changes to the \s-1API\s0. 5524The major version 4 introduced some incompatible changes to the \s-1API.\s0
5516.PP 5525.PP
5517At the moment, the \f(CW\*(C`ev.h\*(C'\fR header file provides compatibility definitions 5526At the moment, the \f(CW\*(C`ev.h\*(C'\fR header file provides compatibility definitions
5518for all changes, so most programs should still compile. The compatibility 5527for all changes, so most programs should still compile. The compatibility
5519layer might be removed in later versions of libev, so better update to the 5528layer might be removed in later versions of libev, so better update to the
5520new \s-1API\s0 early than late. 5529new \s-1API\s0 early than late.
5521.ie n .IP """EV_COMPAT3"" backwards compatibility mechanism" 4 5530.ie n .IP """EV_COMPAT3"" backwards compatibility mechanism" 4
5522.el .IP "\f(CWEV_COMPAT3\fR backwards compatibility mechanism" 4 5531.el .IP "\f(CWEV_COMPAT3\fR backwards compatibility mechanism" 4
5523.IX Item "EV_COMPAT3 backwards compatibility mechanism" 5532.IX Item "EV_COMPAT3 backwards compatibility mechanism"
5524The backward compatibility mechanism can be controlled by 5533The backward compatibility mechanism can be controlled by
5525\&\f(CW\*(C`EV_COMPAT3\*(C'\fR. See \*(L"\s-1PREPROCESSOR\s0 \s-1SYMBOLS/MACROS\s0\*(R" in the \*(L"\s-1EMBEDDING\s0\*(R" 5534\&\f(CW\*(C`EV_COMPAT3\*(C'\fR. See \*(L"\s-1PREPROCESSOR SYMBOLS/MACROS\*(R"\s0 in the \*(L"\s-1EMBEDDING\*(R"\s0
5526section. 5535section.
5527.ie n .IP """ev_default_destroy"" and ""ev_default_fork"" have been removed" 4 5536.ie n .IP """ev_default_destroy"" and ""ev_default_fork"" have been removed" 4
5528.el .IP "\f(CWev_default_destroy\fR and \f(CWev_default_fork\fR have been removed" 4 5537.el .IP "\f(CWev_default_destroy\fR and \f(CWev_default_fork\fR have been removed" 4
5529.IX Item "ev_default_destroy and ev_default_fork have been removed" 5538.IX Item "ev_default_destroy and ev_default_fork have been removed"
5530These calls can be replaced easily by their \f(CW\*(C`ev_loop_xxx\*(C'\fR counterparts: 5539These calls can be replaced easily by their \f(CW\*(C`ev_loop_xxx\*(C'\fR counterparts:
… …
5570.SH "GLOSSARY" 5579.SH "GLOSSARY"
5571.IX Header "GLOSSARY" 5580.IX Header "GLOSSARY"
5572.IP "active" 4 5581.IP "active" 4
5573.IX Item "active" 5582.IX Item "active"
5574A watcher is active as long as it has been started and not yet stopped. 5583A watcher is active as long as it has been started and not yet stopped.
5575See \*(L"\s-1WATCHER\s0 \s-1STATES\s0\*(R" for details. 5584See \*(L"\s-1WATCHER STATES\*(R"\s0 for details.
5576.IP "application" 4 5585.IP "application" 4
5577.IX Item "application" 5586.IX Item "application"
5578In this document, an application is whatever is using libev. 5587In this document, an application is whatever is using libev.
5579.IP "backend" 4 5588.IP "backend" 4
5580.IX Item "backend" 5589.IX Item "backend"
… …
5607The model used to describe how an event loop handles and processes 5616The model used to describe how an event loop handles and processes
5608watchers and events. 5617watchers and events.
5609.IP "pending" 4 5618.IP "pending" 4
5610.IX Item "pending" 5619.IX Item "pending"
5611A watcher is pending as soon as the corresponding event has been 5620A watcher is pending as soon as the corresponding event has been
5612detected. See \*(L"\s-1WATCHER\s0 \s-1STATES\s0\*(R" for details. 5621detected. See \*(L"\s-1WATCHER STATES\*(R"\s0 for details.
5613.IP "real time" 4 5622.IP "real time" 4
5614.IX Item "real time" 5623.IX Item "real time"
5615The physical time that is observed. It is apparently strictly monotonic :) 5624The physical time that is observed. It is apparently strictly monotonic :)
5616.IP "wall-clock time" 4 5625.IP "wall-clock time" 4
5617.IX Item "wall-clock time" 5626.IX Item "wall-clock time"

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