ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/libev/ev.3
(Generate patch)

Comparing libev/ev.3 (file contents):
Revision 1.41 by root, Fri Dec 7 20:13:09 2007 UTC vs.
Revision 1.44 by root, Sat Dec 8 15:30:26 2007 UTC

… …
127.\} 127.\}
128.rm #[ #] #H #V #F C 128.rm #[ #] #H #V #F C
129.\" ======================================================================== 129.\" ========================================================================
130.\" 130.\"
131.IX Title ""<STANDARD INPUT>" 1" 131.IX Title ""<STANDARD INPUT>" 1"
132.TH "<STANDARD INPUT>" 1 "2007-12-07" "perl v5.8.8" "User Contributed Perl Documentation" 132.TH "<STANDARD INPUT>" 1 "2007-12-08" "perl v5.8.8" "User Contributed Perl Documentation"
133.SH "NAME" 133.SH "NAME"
134libev \- a high performance full\-featured event loop written in C 134libev \- a high performance full\-featured event loop written in C
135.SH "SYNOPSIS" 135.SH "SYNOPSIS"
136.IX Header "SYNOPSIS" 136.IX Header "SYNOPSIS"
137.Vb 1 137.Vb 1
… …
889.IP "bool ev_is_pending (ev_TYPE *watcher)" 4 889.IP "bool ev_is_pending (ev_TYPE *watcher)" 4
890.IX Item "bool ev_is_pending (ev_TYPE *watcher)" 890.IX Item "bool ev_is_pending (ev_TYPE *watcher)"
891Returns a true value iff the watcher is pending, (i.e. it has outstanding 891Returns a true value iff the watcher is pending, (i.e. it has outstanding
892events but its callback has not yet been invoked). As long as a watcher 892events but its callback has not yet been invoked). As long as a watcher
893is pending (but not active) you must not call an init function on it (but 893is pending (but not active) you must not call an init function on it (but
894\&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe) and you must make sure the watcher is available to 894\&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe), you must not change its priority, and you must
895libev (e.g. you cnanot \f(CW\*(C`free ()\*(C'\fR it). 895make sure the watcher is available to libev (e.g. you cannot \f(CW\*(C`free ()\*(C'\fR
896it).
896.IP "callback ev_cb (ev_TYPE *watcher)" 4 897.IP "callback ev_cb (ev_TYPE *watcher)" 4
897.IX Item "callback ev_cb (ev_TYPE *watcher)" 898.IX Item "callback ev_cb (ev_TYPE *watcher)"
898Returns the callback currently set on the watcher. 899Returns the callback currently set on the watcher.
899.IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 900.IP "ev_cb_set (ev_TYPE *watcher, callback)" 4
900.IX Item "ev_cb_set (ev_TYPE *watcher, callback)" 901.IX Item "ev_cb_set (ev_TYPE *watcher, callback)"
… …
918watchers on the same event and make sure one is called first. 919watchers on the same event and make sure one is called first.
919.Sp 920.Sp
920If you need to suppress invocation when higher priority events are pending 921If you need to suppress invocation when higher priority events are pending
921you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality. 922you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality.
922.Sp 923.Sp
924You \fImust not\fR change the priority of a watcher as long as it is active or
925pending.
926.Sp
923The default priority used by watchers when no priority has been set is 927The default priority used by watchers when no priority has been set is
924always \f(CW0\fR, which is supposed to not be too high and not be too low :). 928always \f(CW0\fR, which is supposed to not be too high and not be too low :).
925.Sp 929.Sp
926Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is 930Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is
927fine, as long as you do not mind that the priority value you query might 931fine, as long as you do not mind that the priority value you query might
928or might not have been adjusted to be within valid range. 932or might not have been adjusted to be within valid range.
933.IP "ev_invoke (loop, ev_TYPE *watcher, int revents)" 4
934.IX Item "ev_invoke (loop, ev_TYPE *watcher, int revents)"
935Invoke the \f(CW\*(C`watcher\*(C'\fR with the given \f(CW\*(C`loop\*(C'\fR and \f(CW\*(C`revents\*(C'\fR. Neither
936\&\f(CW\*(C`loop\*(C'\fR nor \f(CW\*(C`revents\*(C'\fR need to be valid as long as the watcher callback
937can deal with that fact.
938.IP "int ev_clear_pending (loop, ev_TYPE *watcher)" 4
939.IX Item "int ev_clear_pending (loop, ev_TYPE *watcher)"
940If the watcher is pending, this function returns clears its pending status
941and returns its \f(CW\*(C`revents\*(C'\fR bitset (as if its callback was invoked). If the
942watcher isn't pending it does nothing and returns \f(CW0\fR.
929.Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0" 943.Sh "\s-1ASSOCIATING\s0 \s-1CUSTOM\s0 \s-1DATA\s0 \s-1WITH\s0 A \s-1WATCHER\s0"
930.IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" 944.IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER"
931Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change 945Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change
932and read at any time, libev will completely ignore it. This can be used 946and read at any time, libev will completely ignore it. This can be used
933to associate arbitrary data with your watcher. If you need more data and 947to associate arbitrary data with your watcher. If you need more data and
… …
1630.PD 1644.PD
1631Initialises and configures the prepare or check watcher \- they have no 1645Initialises and configures the prepare or check watcher \- they have no
1632parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR 1646parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR
1633macros, but using them is utterly, utterly and completely pointless. 1647macros, but using them is utterly, utterly and completely pointless.
1634.PP 1648.PP
1635Example: To include a library such as adns, you would add \s-1IO\s0 watchers 1649There are a number of principal ways to embed other event loops or modules
1636and a timeout watcher in a prepare handler, as required by libadns, and 1650into libev. Here are some ideas on how to include libadns into libev
1651(there is a Perl module named \f(CW\*(C`EV::ADNS\*(C'\fR that does this, which you could
1652use for an actually working example. Another Perl module named \f(CW\*(C`EV::Glib\*(C'\fR
1653embeds a Glib main context into libev, and finally, \f(CW\*(C`Glib::EV\*(C'\fR embeds \s-1EV\s0
1654into the Glib event loop).
1655.PP
1656Method 1: Add \s-1IO\s0 watchers and a timeout watcher in a prepare handler,
1637in a check watcher, destroy them and call into libadns. What follows is 1657and in a check watcher, destroy them and call into libadns. What follows
1638pseudo-code only of course: 1658is pseudo-code only of course. This requires you to either use a low
1659priority for the check watcher or use \f(CW\*(C`ev_clear_pending\*(C'\fR explicitly, as
1660the callbacks for the IO/timeout watchers might not have been called yet.
1639.PP 1661.PP
1640.Vb 2 1662.Vb 2
1641\& static ev_io iow [nfd]; 1663\& static ev_io iow [nfd];
1642\& static ev_timer tw; 1664\& static ev_timer tw;
1643.Ve 1665.Ve
1644.PP 1666.PP
1645.Vb 9 1667.Vb 4
1646\& static void 1668\& static void
1647\& io_cb (ev_loop *loop, ev_io *w, int revents) 1669\& io_cb (ev_loop *loop, ev_io *w, int revents)
1648\& { 1670\& {
1649\& // set the relevant poll flags
1650\& // could also call adns_processreadable etc. here
1651\& struct pollfd *fd = (struct pollfd *)w->data;
1652\& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN;
1653\& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT;
1654\& } 1671\& }
1655.Ve 1672.Ve
1656.PP 1673.PP
1657.Vb 8 1674.Vb 8
1658\& // create io watchers for each fd and a timer before blocking 1675\& // create io watchers for each fd and a timer before blocking
… …
1670\& ev_timer_init (&tw, 0, timeout * 1e-3); 1687\& ev_timer_init (&tw, 0, timeout * 1e-3);
1671\& ev_timer_start (loop, &tw); 1688\& ev_timer_start (loop, &tw);
1672.Ve 1689.Ve
1673.PP 1690.PP
1674.Vb 6 1691.Vb 6
1675\& // create on ev_io per pollfd 1692\& // create one ev_io per pollfd
1676\& for (int i = 0; i < nfd; ++i) 1693\& for (int i = 0; i < nfd; ++i)
1677\& { 1694\& {
1678\& ev_io_init (iow + i, io_cb, fds [i].fd, 1695\& ev_io_init (iow + i, io_cb, fds [i].fd,
1679\& ((fds [i].events & POLLIN ? EV_READ : 0) 1696\& ((fds [i].events & POLLIN ? EV_READ : 0)
1680\& | (fds [i].events & POLLOUT ? EV_WRITE : 0))); 1697\& | (fds [i].events & POLLOUT ? EV_WRITE : 0)));
1681.Ve 1698.Ve
1682.PP 1699.PP
1683.Vb 5 1700.Vb 4
1684\& fds [i].revents = 0; 1701\& fds [i].revents = 0;
1685\& iow [i].data = fds + i;
1686\& ev_io_start (loop, iow + i); 1702\& ev_io_start (loop, iow + i);
1687\& } 1703\& }
1688\& } 1704\& }
1689.Ve 1705.Ve
1690.PP 1706.PP
… …
1694\& adns_check_cb (ev_loop *loop, ev_check *w, int revents) 1710\& adns_check_cb (ev_loop *loop, ev_check *w, int revents)
1695\& { 1711\& {
1696\& ev_timer_stop (loop, &tw); 1712\& ev_timer_stop (loop, &tw);
1697.Ve 1713.Ve
1698.PP 1714.PP
1699.Vb 2 1715.Vb 8
1700\& for (int i = 0; i < nfd; ++i) 1716\& for (int i = 0; i < nfd; ++i)
1717\& {
1718\& // set the relevant poll flags
1719\& // could also call adns_processreadable etc. here
1720\& struct pollfd *fd = fds + i;
1721\& int revents = ev_clear_pending (iow + i);
1722\& if (revents & EV_READ ) fd->revents |= fd->events & POLLIN;
1723\& if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT;
1724.Ve
1725.PP
1726.Vb 3
1727\& // now stop the watcher
1701\& ev_io_stop (loop, iow + i); 1728\& ev_io_stop (loop, iow + i);
1729\& }
1702.Ve 1730.Ve
1703.PP 1731.PP
1704.Vb 2 1732.Vb 2
1705\& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop)); 1733\& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));
1734\& }
1735.Ve
1736.PP
1737Method 2: This would be just like method 1, but you run \f(CW\*(C`adns_afterpoll\*(C'\fR
1738in the prepare watcher and would dispose of the check watcher.
1739.PP
1740Method 3: If the module to be embedded supports explicit event
1741notification (adns does), you can also make use of the actual watcher
1742callbacks, and only destroy/create the watchers in the prepare watcher.
1743.PP
1744.Vb 5
1745\& static void
1746\& timer_cb (EV_P_ ev_timer *w, int revents)
1747\& {
1748\& adns_state ads = (adns_state)w->data;
1749\& update_now (EV_A);
1750.Ve
1751.PP
1752.Vb 2
1753\& adns_processtimeouts (ads, &tv_now);
1754\& }
1755.Ve
1756.PP
1757.Vb 5
1758\& static void
1759\& io_cb (EV_P_ ev_io *w, int revents)
1760\& {
1761\& adns_state ads = (adns_state)w->data;
1762\& update_now (EV_A);
1763.Ve
1764.PP
1765.Vb 3
1766\& if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now);
1767\& if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now);
1768\& }
1769.Ve
1770.PP
1771.Vb 1
1772\& // do not ever call adns_afterpoll
1773.Ve
1774.PP
1775Method 4: Do not use a prepare or check watcher because the module you
1776want to embed is too inflexible to support it. Instead, youc na override
1777their poll function. The drawback with this solution is that the main
1778loop is now no longer controllable by \s-1EV\s0. The \f(CW\*(C`Glib::EV\*(C'\fR module does
1779this.
1780.PP
1781.Vb 4
1782\& static gint
1783\& event_poll_func (GPollFD *fds, guint nfds, gint timeout)
1784\& {
1785\& int got_events = 0;
1786.Ve
1787.PP
1788.Vb 2
1789\& for (n = 0; n < nfds; ++n)
1790\& // create/start io watcher that sets the relevant bits in fds[n] and increment got_events
1791.Ve
1792.PP
1793.Vb 2
1794\& if (timeout >= 0)
1795\& // create/start timer
1796.Ve
1797.PP
1798.Vb 2
1799\& // poll
1800\& ev_loop (EV_A_ 0);
1801.Ve
1802.PP
1803.Vb 3
1804\& // stop timer again
1805\& if (timeout >= 0)
1806\& ev_timer_stop (EV_A_ &to);
1807.Ve
1808.PP
1809.Vb 3
1810\& // stop io watchers again - their callbacks should have set
1811\& for (n = 0; n < nfds; ++n)
1812\& ev_io_stop (EV_A_ iow [n]);
1813.Ve
1814.PP
1815.Vb 2
1816\& return got_events;
1706\& } 1817\& }
1707.Ve 1818.Ve
1708.ie n .Sh """ev_embed"" \- when one backend isn't enough..." 1819.ie n .Sh """ev_embed"" \- when one backend isn't enough..."
1709.el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..." 1820.el .Sh "\f(CWev_embed\fP \- when one backend isn't enough..."
1710.IX Subsection "ev_embed - when one backend isn't enough..." 1821.IX Subsection "ev_embed - when one backend isn't enough..."
… …
1899This automatically includes \fIev.h\fR and puts all of its definitions (many 2010This automatically includes \fIev.h\fR and puts all of its definitions (many
1900of them macros) into the global namespace. All \*(C+ specific things are 2011of them macros) into the global namespace. All \*(C+ specific things are
1901put into the \f(CW\*(C`ev\*(C'\fR namespace. It should support all the same embedding 2012put into the \f(CW\*(C`ev\*(C'\fR namespace. It should support all the same embedding
1902options as \fIev.h\fR, most notably \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. 2013options as \fIev.h\fR, most notably \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR.
1903.PP 2014.PP
1904Care has been taken to keep the overhead low. The only data member added 2015Care has been taken to keep the overhead low. The only data member the \*(C+
1905to the C\-style watchers is the event loop the watcher is associated with 2016classes add (compared to plain C\-style watchers) is the event loop pointer
1906(or no additional members at all if you disable \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR when 2017that the watcher is associated with (or no additional members at all if
1907embedding libev). 2018you disable \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR when embedding libev).
1908.PP 2019.PP
1909Currently, functions and static and non-static member functions can be 2020Currently, functions, and static and non-static member functions can be
1910used as callbacks. Other types should be easy to add as long as they only 2021used as callbacks. Other types should be easy to add as long as they only
1911need one additional pointer for context. If you need support for other 2022need one additional pointer for context. If you need support for other
1912types of functors please contact the author (preferably after implementing 2023types of functors please contact the author (preferably after implementing
1913it). 2024it).
1914.PP 2025.PP
… …
1978.Vb 3 2089.Vb 3
1979\& myclass obj; 2090\& myclass obj;
1980\& ev::io iow; 2091\& ev::io iow;
1981\& iow.set <myclass, &myclass::io_cb> (&obj); 2092\& iow.set <myclass, &myclass::io_cb> (&obj);
1982.Ve 2093.Ve
1983.IP "w\->set (void (*function)(watcher &w, int), void *data = 0)" 4 2094.IP "w\->set<function> (void *data = 0)" 4
1984.IX Item "w->set (void (*function)(watcher &w, int), void *data = 0)" 2095.IX Item "w->set<function> (void *data = 0)"
1985Also sets a callback, but uses a static method or plain function as 2096Also sets a callback, but uses a static method or plain function as
1986callback. The optional \f(CW\*(C`data\*(C'\fR argument will be stored in the watcher's 2097callback. The optional \f(CW\*(C`data\*(C'\fR argument will be stored in the watcher's
1987\&\f(CW\*(C`data\*(C'\fR member and is free for you to use. 2098\&\f(CW\*(C`data\*(C'\fR member and is free for you to use.
1988.Sp 2099.Sp
2100The prototype of the \f(CW\*(C`function\*(C'\fR must be \f(CW\*(C`void (*)(ev::TYPE &w, int)\*(C'\fR.
2101.Sp
1989See the method\-\f(CW\*(C`set\*(C'\fR above for more details. 2102See the method\-\f(CW\*(C`set\*(C'\fR above for more details.
2103.Sp
2104Example:
2105.Sp
2106.Vb 2
2107\& static void io_cb (ev::io &w, int revents) { }
2108\& iow.set <io_cb> ();
2109.Ve
1990.IP "w\->set (struct ev_loop *)" 4 2110.IP "w\->set (struct ev_loop *)" 4
1991.IX Item "w->set (struct ev_loop *)" 2111.IX Item "w->set (struct ev_loop *)"
1992Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only 2112Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only
1993do this when the watcher is inactive (and not pending either). 2113do this when the watcher is inactive (and not pending either).
1994.IP "w\->set ([args])" 4 2114.IP "w\->set ([args])" 4

Diff Legend

– Removed lines
+ Added lines
< Changed lines
> Changed lines