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Comparing libev/ev.3 (file contents):
Revision 1.12 by root, Sat Nov 24 07:20:42 2007 UTC vs.
Revision 1.14 by root, Sat Nov 24 10:10:26 2007 UTC

995(and unfortunately a bit complex). 995(and unfortunately a bit complex).
996.PP 996.PP
997Unlike \f(CW\*(C`ev_timer\*(C'\fR's, they are not based on real time (or relative time) 997Unlike \f(CW\*(C`ev_timer\*(C'\fR's, they are not based on real time (or relative time)
998but on wallclock time (absolute time). You can tell a periodic watcher 998but on wallclock time (absolute time). You can tell a periodic watcher
999to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a 999to trigger \*(L"at\*(R" some specific point in time. For example, if you tell a
1000periodic watcher to trigger in 10 seconds (by specifiying e.g. c<ev_now () 1000periodic watcher to trigger in 10 seconds (by specifiying e.g. \f(CW\*(C`ev_now ()
1001+ 10.>) and then reset your system clock to the last year, then it will 1001+ 10.\*(C'\fR) and then reset your system clock to the last year, then it will
1002take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger 1002take a year to trigger the event (unlike an \f(CW\*(C`ev_timer\*(C'\fR, which would trigger
1003roughly 10 seconds later and of course not if you reset your system time 1003roughly 10 seconds later and of course not if you reset your system time
1004again). 1004again).
1005.PP 1005.PP
1006They can also be used to implement vastly more complex timers, such as 1006They can also be used to implement vastly more complex timers, such as
1432.IP "* The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need to use the libev header file and library." 4 1432.IP "* The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need to use the libev header file and library." 4
1433.IX Item "The libev emulation is not ABI compatible to libevent, you need to use the libev header file and library." 1433.IX Item "The libev emulation is not ABI compatible to libevent, you need to use the libev header file and library."
1434.PD 1434.PD
1435.SH "\*(C+ SUPPORT" 1435.SH "\*(C+ SUPPORT"
1436.IX Header " SUPPORT" 1436.IX Header " SUPPORT"
1437\&\s-1TBD\s0. 1437Libev comes with some simplistic wrapper classes for \*(C+ that mainly allow
1438you to use some convinience methods to start/stop watchers and also change
1439the callback model to a model using method callbacks on objects.
1440.PP
1441To use it,
1442.PP
1443.Vb 1
1444\& #include <ev++.h>
1445.Ve
1446.PP
1447(it is not installed by default). This automatically includes \fIev.h\fR
1448and puts all of its definitions (many of them macros) into the global
1449namespace. All \*(C+ specific things are put into the \f(CW\*(C`ev\*(C'\fR namespace.
1450.PP
1451It should support all the same embedding options as \fIev.h\fR, most notably
1452\&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR.
1453.PP
1454Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace:
1455.ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4
1456.el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4
1457.IX Item "ev::READ, ev::WRITE etc."
1458These are just enum values with the same values as the \f(CW\*(C`EV_READ\*(C'\fR etc.
1459macros from \fIev.h\fR.
1460.ie n .IP """ev::tstamp""\fR, \f(CW""ev::now""" 4
1461.el .IP "\f(CWev::tstamp\fR, \f(CWev::now\fR" 4
1462.IX Item "ev::tstamp, ev::now"
1463Aliases to the same types/functions as with the \f(CW\*(C`ev_\*(C'\fR prefix.
1464.ie n .IP """ev::io""\fR, \f(CW""ev::timer""\fR, \f(CW""ev::periodic""\fR, \f(CW""ev::idle""\fR, \f(CW""ev::sig"" etc." 4
1465.el .IP "\f(CWev::io\fR, \f(CWev::timer\fR, \f(CWev::periodic\fR, \f(CWev::idle\fR, \f(CWev::sig\fR etc." 4
1466.IX Item "ev::io, ev::timer, ev::periodic, ev::idle, ev::sig etc."
1467For each \f(CW\*(C`ev_TYPE\*(C'\fR watcher in \fIev.h\fR there is a corresponding class of
1468the same name in the \f(CW\*(C`ev\*(C'\fR namespace, with the exception of \f(CW\*(C`ev_signal\*(C'\fR
1469which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro
1470defines by many implementations.
1471.Sp
1472All of those classes have these methods:
1473.RS 4
1474.IP "ev::TYPE::TYPE (object *, object::method *)" 4
1475.IX Item "ev::TYPE::TYPE (object *, object::method *)"
1476.PD 0
1477.IP "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" 4
1478.IX Item "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)"
1479.IP "ev::TYPE::~TYPE" 4
1480.IX Item "ev::TYPE::~TYPE"
1481.PD
1482The constructor takes a pointer to an object and a method pointer to
1483the event handler callback to call in this class. The constructor calls
1484\&\f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the \f(CW\*(C`set\*(C'\fR method
1485before starting it. If you do not specify a loop then the constructor
1486automatically associates the default loop with this watcher.
1487.Sp
1488The destructor automatically stops the watcher if it is active.
1489.IP "w\->set (struct ev_loop *)" 4
1490.IX Item "w->set (struct ev_loop *)"
1491Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only
1492do this when the watcher is inactive (and not pending either).
1493.IP "w\->set ([args])" 4
1494.IX Item "w->set ([args])"
1495Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be
1496called at least once. Unlike the C counterpart, an active watcher gets
1497automatically stopped and restarted.
1498.IP "w\->start ()" 4
1499.IX Item "w->start ()"
1500Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument as the
1501constructor already takes the loop.
1502.IP "w\->stop ()" 4
1503.IX Item "w->stop ()"
1504Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument.
1505.ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4
1506.el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4
1507.IX Item "w->again () ev::timer, ev::periodic only"
1508For \f(CW\*(C`ev::timer\*(C'\fR and \f(CW\*(C`ev::periodic\*(C'\fR, this invokes the corresponding
1509\&\f(CW\*(C`ev_TYPE_again\*(C'\fR function.
1510.ie n .IP "w\->sweep () ""ev::embed"" only" 4
1511.el .IP "w\->sweep () \f(CWev::embed\fR only" 4
1512.IX Item "w->sweep () ev::embed only"
1513Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR.
1514.RE
1515.RS 4
1516.RE
1517.PP
1518Example: Define a class with an \s-1IO\s0 and idle watcher, start one of them in
1519the constructor.
1520.PP
1521.Vb 4
1522\& class myclass
1523\& {
1524\& ev_io io; void io_cb (ev::io &w, int revents);
1525\& ev_idle idle void idle_cb (ev::idle &w, int revents);
1526.Ve
1527.PP
1528.Vb 2
1529\& myclass ();
1530\& }
1531.Ve
1532.PP
1533.Vb 6
1534\& myclass::myclass (int fd)
1535\& : io (this, &myclass::io_cb),
1536\& idle (this, &myclass::idle_cb)
1537\& {
1538\& io.start (fd, ev::READ);
1539\& }
1540.Ve
1541.SH "EMBEDDING"
1542.IX Header "EMBEDDING"
1543Libev can (and often is) directly embedded into host
1544applications. Examples of applications that embed it include the Deliantra
1545Game Server, the \s-1EV\s0 perl module, the \s-1GNU\s0 Virtual Private Ethernet (gvpe)
1546and rxvt\-unicode.
1547.PP
1548The goal is to enable you to just copy the neecssary files into your
1549source directory without having to change even a single line in them, so
1550you can easily upgrade by simply copying (or having a checked-out copy of
1551libev somewhere in your source tree).
1552.Sh "\s-1FILESETS\s0"
1553.IX Subsection "FILESETS"
1554Depending on what features you need you need to include one or more sets of files
1555in your app.
1556.PP
1557\fI\s-1CORE\s0 \s-1EVENT\s0 \s-1LOOP\s0\fR
1558.IX Subsection "CORE EVENT LOOP"
1559.PP
1560To include only the libev core (all the \f(CW\*(C`ev_*\*(C'\fR functions), with manual
1561configuration (no autoconf):
1562.PP
1563.Vb 2
1564\& #define EV_STANDALONE 1
1565\& #include "ev.c"
1566.Ve
1567.PP
1568This will automatically include \fIev.h\fR, too, and should be done in a
1569single C source file only to provide the function implementations. To use
1570it, do the same for \fIev.h\fR in all files wishing to use this \s-1API\s0 (best
1571done by writing a wrapper around \fIev.h\fR that you can include instead and
1572where you can put other configuration options):
1573.PP
1574.Vb 2
1575\& #define EV_STANDALONE 1
1576\& #include "ev.h"
1577.Ve
1578.PP
1579Both header files and implementation files can be compiled with a \*(C+
1580compiler (at least, thats a stated goal, and breakage will be treated
1581as a bug).
1582.PP
1583You need the following files in your source tree, or in a directory
1584in your include path (e.g. in libev/ when using \-Ilibev):
1585.PP
1586.Vb 4
1587\& ev.h
1588\& ev.c
1589\& ev_vars.h
1590\& ev_wrap.h
1591.Ve
1592.PP
1593.Vb 1
1594\& ev_win32.c required on win32 platforms only
1595.Ve
1596.PP
1597.Vb 5
1598\& ev_select.c only when select backend is enabled (which is is by default)
1599\& ev_poll.c only when poll backend is enabled (disabled by default)
1600\& ev_epoll.c only when the epoll backend is enabled (disabled by default)
1601\& ev_kqueue.c only when the kqueue backend is enabled (disabled by default)
1602\& ev_port.c only when the solaris port backend is enabled (disabled by default)
1603.Ve
1604.PP
1605\&\fIev.c\fR includes the backend files directly when enabled, so you only need
1606to compile a single file.
1607.PP
1608\fI\s-1LIBEVENT\s0 \s-1COMPATIBILITY\s0 \s-1API\s0\fR
1609.IX Subsection "LIBEVENT COMPATIBILITY API"
1610.PP
1611To include the libevent compatibility \s-1API\s0, also include:
1612.PP
1613.Vb 1
1614\& #include "event.c"
1615.Ve
1616.PP
1617in the file including \fIev.c\fR, and:
1618.PP
1619.Vb 1
1620\& #include "event.h"
1621.Ve
1622.PP
1623in the files that want to use the libevent \s-1API\s0. This also includes \fIev.h\fR.
1624.PP
1625You need the following additional files for this:
1626.PP
1627.Vb 2
1628\& event.h
1629\& event.c
1630.Ve
1631.PP
1632\fI\s-1AUTOCONF\s0 \s-1SUPPORT\s0\fR
1633.IX Subsection "AUTOCONF SUPPORT"
1634.PP
1635Instead of using \f(CW\*(C`EV_STANDALONE=1\*(C'\fR and providing your config in
1636whatever way you want, you can also \f(CW\*(C`m4_include([libev.m4])\*(C'\fR in your
1637\&\fIconfigure.ac\fR and leave \f(CW\*(C`EV_STANDALONE\*(C'\fR off. \fIev.c\fR will then include
1638\&\fIconfig.h\fR and configure itself accordingly.
1639.PP
1640For this of course you need the m4 file:
1641.PP
1642.Vb 1
1643\& libev.m4
1644.Ve
1645.Sh "\s-1PREPROCESSOR\s0 \s-1SYMBOLS/MACROS\s0"
1646.IX Subsection "PREPROCESSOR SYMBOLS/MACROS"
1647Libev can be configured via a variety of preprocessor symbols you have to define
1648before including any of its files. The default is not to build for multiplicity
1649and only include the select backend.
1650.IP "\s-1EV_STANDALONE\s0" 4
1651.IX Item "EV_STANDALONE"
1652Must always be \f(CW1\fR if you do not use autoconf configuration, which
1653keeps libev from including \fIconfig.h\fR, and it also defines dummy
1654implementations for some libevent functions (such as logging, which is not
1655supported). It will also not define any of the structs usually found in
1656\&\fIevent.h\fR that are not directly supported by the libev core alone.
1657.IP "\s-1EV_USE_MONOTONIC\s0" 4
1658.IX Item "EV_USE_MONOTONIC"
1659If defined to be \f(CW1\fR, libev will try to detect the availability of the
1660monotonic clock option at both compiletime and runtime. Otherwise no use
1661of the monotonic clock option will be attempted. If you enable this, you
1662usually have to link against librt or something similar. Enabling it when
1663the functionality isn't available is safe, though, althoguh you have
1664to make sure you link against any libraries where the \f(CW\*(C`clock_gettime\*(C'\fR
1665function is hiding in (often \fI\-lrt\fR).
1666.IP "\s-1EV_USE_REALTIME\s0" 4
1667.IX Item "EV_USE_REALTIME"
1668If defined to be \f(CW1\fR, libev will try to detect the availability of the
1669realtime clock option at compiletime (and assume its availability at
1670runtime if successful). Otherwise no use of the realtime clock option will
1671be attempted. This effectively replaces \f(CW\*(C`gettimeofday\*(C'\fR by \f(CW\*(C`clock_get
1672(CLOCK_REALTIME, ...)\*(C'\fR and will not normally affect correctness. See tzhe note about libraries
1673in the description of \f(CW\*(C`EV_USE_MONOTONIC\*(C'\fR, though.
1674.IP "\s-1EV_USE_SELECT\s0" 4
1675.IX Item "EV_USE_SELECT"
1676If undefined or defined to be \f(CW1\fR, libev will compile in support for the
1677\&\f(CW\*(C`select\*(C'\fR(2) backend. No attempt at autodetection will be done: if no
1678other method takes over, select will be it. Otherwise the select backend
1679will not be compiled in.
1680.IP "\s-1EV_SELECT_USE_FD_SET\s0" 4
1681.IX Item "EV_SELECT_USE_FD_SET"
1682If defined to \f(CW1\fR, then the select backend will use the system \f(CW\*(C`fd_set\*(C'\fR
1683structure. This is useful if libev doesn't compile due to a missing
1684\&\f(CW\*(C`NFDBITS\*(C'\fR or \f(CW\*(C`fd_mask\*(C'\fR definition or it misguesses the bitset layout on
1685exotic systems. This usually limits the range of file descriptors to some
1686low limit such as 1024 or might have other limitations (winsocket only
1687allows 64 sockets). The \f(CW\*(C`FD_SETSIZE\*(C'\fR macro, set before compilation, might
1688influence the size of the \f(CW\*(C`fd_set\*(C'\fR used.
1689.IP "\s-1EV_SELECT_IS_WINSOCKET\s0" 4
1690.IX Item "EV_SELECT_IS_WINSOCKET"
1691When defined to \f(CW1\fR, the select backend will assume that
1692select/socket/connect etc. don't understand file descriptors but
1693wants osf handles on win32 (this is the case when the select to
1694be used is the winsock select). This means that it will call
1695\&\f(CW\*(C`_get_osfhandle\*(C'\fR on the fd to convert it to an \s-1OS\s0 handle. Otherwise,
1696it is assumed that all these functions actually work on fds, even
1697on win32. Should not be defined on non\-win32 platforms.
1698.IP "\s-1EV_USE_POLL\s0" 4
1699.IX Item "EV_USE_POLL"
1700If defined to be \f(CW1\fR, libev will compile in support for the \f(CW\*(C`poll\*(C'\fR(2)
1701backend. Otherwise it will be enabled on non\-win32 platforms. It
1702takes precedence over select.
1703.IP "\s-1EV_USE_EPOLL\s0" 4
1704.IX Item "EV_USE_EPOLL"
1705If defined to be \f(CW1\fR, libev will compile in support for the Linux
1706\&\f(CW\*(C`epoll\*(C'\fR(7) backend. Its availability will be detected at runtime,
1707otherwise another method will be used as fallback. This is the
1708preferred backend for GNU/Linux systems.
1709.IP "\s-1EV_USE_KQUEUE\s0" 4
1710.IX Item "EV_USE_KQUEUE"
1711If defined to be \f(CW1\fR, libev will compile in support for the \s-1BSD\s0 style
1712\&\f(CW\*(C`kqueue\*(C'\fR(2) backend. Its actual availability will be detected at runtime,
1713otherwise another method will be used as fallback. This is the preferred
1714backend for \s-1BSD\s0 and BSD-like systems, although on most BSDs kqueue only
1715supports some types of fds correctly (the only platform we found that
1716supports ptys for example was NetBSD), so kqueue might be compiled in, but
1717not be used unless explicitly requested. The best way to use it is to find
1718out wether kqueue supports your type of fd properly and use an embedded
1719kqueue loop.
1720.IP "\s-1EV_USE_PORT\s0" 4
1721.IX Item "EV_USE_PORT"
1722If defined to be \f(CW1\fR, libev will compile in support for the Solaris
172310 port style backend. Its availability will be detected at runtime,
1724otherwise another method will be used as fallback. This is the preferred
1725backend for Solaris 10 systems.
1726.IP "\s-1EV_USE_DEVPOLL\s0" 4
1727.IX Item "EV_USE_DEVPOLL"
1728reserved for future expansion, works like the \s-1USE\s0 symbols above.
1729.IP "\s-1EV_H\s0" 4
1730.IX Item "EV_H"
1731The name of the \fIev.h\fR header file used to include it. The default if
1732undefined is \f(CW\*(C`<ev.h>\*(C'\fR in \fIevent.h\fR and \f(CW"ev.h"\fR in \fIev.c\fR. This
1733can be used to virtually rename the \fIev.h\fR header file in case of conflicts.
1734.IP "\s-1EV_CONFIG_H\s0" 4
1735.IX Item "EV_CONFIG_H"
1736If \f(CW\*(C`EV_STANDALONE\*(C'\fR isn't \f(CW1\fR, this variable can be used to override
1737\&\fIev.c\fR's idea of where to find the \fIconfig.h\fR file, similarly to
1738\&\f(CW\*(C`EV_H\*(C'\fR, above.
1739.IP "\s-1EV_EVENT_H\s0" 4
1740.IX Item "EV_EVENT_H"
1741Similarly to \f(CW\*(C`EV_H\*(C'\fR, this macro can be used to override \fIevent.c\fR's idea
1742of how the \fIevent.h\fR header can be found.
1743.IP "\s-1EV_PROTOTYPES\s0" 4
1744.IX Item "EV_PROTOTYPES"
1745If defined to be \f(CW0\fR, then \fIev.h\fR will not define any function
1746prototypes, but still define all the structs and other symbols. This is
1747occasionally useful if you want to provide your own wrapper functions
1748around libev functions.
1749.IP "\s-1EV_MULTIPLICITY\s0" 4
1750.IX Item "EV_MULTIPLICITY"
1751If undefined or defined to \f(CW1\fR, then all event-loop-specific functions
1752will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create
1753additional independent event loops. Otherwise there will be no support
1754for multiple event loops and there is no first event loop pointer
1755argument. Instead, all functions act on the single default loop.
1756.IP "\s-1EV_PERIODICS\s0" 4
1757.IX Item "EV_PERIODICS"
1758If undefined or defined to be \f(CW1\fR, then periodic timers are supported,
1759otherwise not. This saves a few kb of code.
1760.IP "\s-1EV_COMMON\s0" 4
1761.IX Item "EV_COMMON"
1762By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining
1763this macro to a something else you can include more and other types of
1764members. You have to define it each time you include one of the files,
1765though, and it must be identical each time.
1766.Sp
1767For example, the perl \s-1EV\s0 module uses something like this:
1768.Sp
1769.Vb 3
1770\& #define EV_COMMON \e
1771\& SV *self; /* contains this struct */ \e
1772\& SV *cb_sv, *fh /* note no trailing ";" */
1773.Ve
1774.IP "\s-1EV_CB_DECLARE\s0(type)" 4
1775.IX Item "EV_CB_DECLARE(type)"
1776.PD 0
1777.IP "\s-1EV_CB_INVOKE\s0(watcher,revents)" 4
1778.IX Item "EV_CB_INVOKE(watcher,revents)"
1779.IP "ev_set_cb(ev,cb)" 4
1780.IX Item "ev_set_cb(ev,cb)"
1781.PD
1782Can be used to change the callback member declaration in each watcher,
1783and the way callbacks are invoked and set. Must expand to a struct member
1784definition and a statement, respectively. See the \fIev.v\fR header file for
1785their default definitions. One possible use for overriding these is to
1786avoid the ev_loop pointer as first argument in all cases, or to use method
1787calls instead of plain function calls in \*(C+.
1788.Sh "\s-1EXAMPLES\s0"
1789.IX Subsection "EXAMPLES"
1790For a real-world example of a program the includes libev
1791verbatim, you can have a look at the \s-1EV\s0 perl module
1792(<http://software.schmorp.de/pkg/EV.html>). It has the libev files in
1793the \fIlibev/\fR subdirectory and includes them in the \fI\s-1EV/EVAPI\s0.h\fR (public
1794interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file
1795will be compiled. It is pretty complex because it provides its own header
1796file.
1797.Sp
1798The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file
1799that everybody includes and which overrides some autoconf choices:
1800.Sp
1801.Vb 4
1802\& #define EV_USE_POLL 0
1803\& #define EV_MULTIPLICITY 0
1804\& #define EV_PERIODICS 0
1805\& #define EV_CONFIG_H <config.h>
1806.Ve
1807.Sp
1808.Vb 1
1809\& #include "ev++.h"
1810.Ve
1811.Sp
1812And a \fIev_cpp.C\fR implementation file that contains libev proper and is compiled:
1813.Sp
1814.Vb 1
1815\& #include "rxvttoolkit.h"
1816.Ve
1817.Sp
1818.Vb 2
1819\& /* darwin has problems with its header files in C++, requiring this namespace juggling */
1820\& using namespace ev;
1821.Ve
1822.Sp
1823.Vb 1
1824\& #include "ev.c"
1825.Ve
1438.SH "AUTHOR" 1826.SH "AUTHOR"
1439.IX Header "AUTHOR" 1827.IX Header "AUTHOR"
1440Marc Lehmann <libev@schmorp.de>. 1828Marc Lehmann <libev@schmorp.de>.

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