… | |
… | |
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" |
134 | libev \- a high performance full\-featured event loop written in C |
134 | libev \- 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 |
… | |
… | |
196 | \& return 0; |
196 | \& return 0; |
197 | \& } |
197 | \& } |
198 | .Ve |
198 | .Ve |
199 | .SH "DESCRIPTION" |
199 | .SH "DESCRIPTION" |
200 | .IX Header "DESCRIPTION" |
200 | .IX Header "DESCRIPTION" |
|
|
201 | The newest version of this document is also available as a html-formatted |
|
|
202 | web page you might find easier to navigate when reading it for the first |
|
|
203 | time: <http://cvs.schmorp.de/libev/ev.html>. |
|
|
204 | .PP |
201 | Libev is an event loop: you register interest in certain events (such as a |
205 | Libev is an event loop: you register interest in certain events (such as a |
202 | file descriptor being readable or a timeout occuring), and it will manage |
206 | file descriptor being readable or a timeout occuring), and it will manage |
203 | these event sources and provide your program with events. |
207 | these event sources and provide your program with events. |
204 | .PP |
208 | .PP |
205 | To do this, it must take more or less complete control over your process |
209 | To do this, it must take more or less complete control over your process |
… | |
… | |
885 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
889 | .IP "bool ev_is_pending (ev_TYPE *watcher)" 4 |
886 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
890 | .IX Item "bool ev_is_pending (ev_TYPE *watcher)" |
887 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
891 | Returns a true value iff the watcher is pending, (i.e. it has outstanding |
888 | events but its callback has not yet been invoked). As long as a watcher |
892 | events but its callback has not yet been invoked). As long as a watcher |
889 | is pending (but not active) you must not call an init function on it (but |
893 | is pending (but not active) you must not call an init function on it (but |
890 | \&\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 |
891 | libev (e.g. you cnanot \f(CW\*(C`free ()\*(C'\fR it). |
895 | make sure the watcher is available to libev (e.g. you cannot \f(CW\*(C`free ()\*(C'\fR |
|
|
896 | it). |
892 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
897 | .IP "callback ev_cb (ev_TYPE *watcher)" 4 |
893 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
898 | .IX Item "callback ev_cb (ev_TYPE *watcher)" |
894 | Returns the callback currently set on the watcher. |
899 | Returns the callback currently set on the watcher. |
895 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
900 | .IP "ev_cb_set (ev_TYPE *watcher, callback)" 4 |
896 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
901 | .IX Item "ev_cb_set (ev_TYPE *watcher, callback)" |
… | |
… | |
914 | watchers on the same event and make sure one is called first. |
919 | watchers on the same event and make sure one is called first. |
915 | .Sp |
920 | .Sp |
916 | If you need to suppress invocation when higher priority events are pending |
921 | If you need to suppress invocation when higher priority events are pending |
917 | you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality. |
922 | you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality. |
918 | .Sp |
923 | .Sp |
|
|
924 | You \fImust not\fR change the priority of a watcher as long as it is active or |
|
|
925 | pending. |
|
|
926 | .Sp |
919 | The default priority used by watchers when no priority has been set is |
927 | The default priority used by watchers when no priority has been set is |
920 | always \f(CW0\fR, which is supposed to not be too high and not be too low :). |
928 | always \f(CW0\fR, which is supposed to not be too high and not be too low :). |
921 | .Sp |
929 | .Sp |
922 | Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is |
930 | Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is |
923 | fine, as long as you do not mind that the priority value you query might |
931 | fine, as long as you do not mind that the priority value you query might |
924 | or might not have been adjusted to be within valid range. |
932 | or 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)" |
|
|
935 | Invoke 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 |
|
|
937 | can 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)" |
|
|
940 | If the watcher is pending, this function returns clears its pending status |
|
|
941 | and returns its \f(CW\*(C`revents\*(C'\fR bitset (as if its callback was invoked). If the |
|
|
942 | watcher isn't pending it does nothing and returns \f(CW0\fR. |
925 | .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" |
926 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
944 | .IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER" |
927 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
945 | Each watcher has, by default, a member \f(CW\*(C`void *data\*(C'\fR that you can change |
928 | and read at any time, libev will completely ignore it. This can be used |
946 | and read at any time, libev will completely ignore it. This can be used |
929 | to associate arbitrary data with your watcher. If you need more data and |
947 | to associate arbitrary data with your watcher. If you need more data and |
… | |
… | |
1040 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
1058 | it is best to always use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning |
1041 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
1059 | \&\f(CW\*(C`EAGAIN\*(C'\fR is far preferable to a program hanging until some data arrives. |
1042 | .PP |
1060 | .PP |
1043 | If you cannot run the fd in non-blocking mode (for example you should not |
1061 | If you cannot run the fd in non-blocking mode (for example you should not |
1044 | play around with an Xlib connection), then you have to seperately re-test |
1062 | play around with an Xlib connection), then you have to seperately re-test |
1045 | wether a file descriptor is really ready with a known-to-be good interface |
1063 | whether a file descriptor is really ready with a known-to-be good interface |
1046 | such as poll (fortunately in our Xlib example, Xlib already does this on |
1064 | such as poll (fortunately in our Xlib example, Xlib already does this on |
1047 | its own, so its quite safe to use). |
1065 | its own, so its quite safe to use). |
1048 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
1066 | .IP "ev_io_init (ev_io *, callback, int fd, int events)" 4 |
1049 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
1067 | .IX Item "ev_io_init (ev_io *, callback, int fd, int events)" |
1050 | .PD 0 |
1068 | .PD 0 |
… | |
… | |
1890 | .PP |
1908 | .PP |
1891 | .Vb 1 |
1909 | .Vb 1 |
1892 | \& #include <ev++.h> |
1910 | \& #include <ev++.h> |
1893 | .Ve |
1911 | .Ve |
1894 | .PP |
1912 | .PP |
1895 | (it is not installed by default). This automatically includes \fIev.h\fR |
1913 | This automatically includes \fIev.h\fR and puts all of its definitions (many |
1896 | and puts all of its definitions (many of them macros) into the global |
1914 | of them macros) into the global namespace. All \*(C+ specific things are |
1897 | namespace. All \*(C+ specific things are put into the \f(CW\*(C`ev\*(C'\fR namespace. |
1915 | put into the \f(CW\*(C`ev\*(C'\fR namespace. It should support all the same embedding |
|
|
1916 | options as \fIev.h\fR, most notably \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
1898 | .PP |
1917 | .PP |
1899 | It should support all the same embedding options as \fIev.h\fR, most notably |
1918 | Care has been taken to keep the overhead low. The only data member the \*(C+ |
1900 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. |
1919 | classes add (compared to plain C\-style watchers) is the event loop pointer |
|
|
1920 | that the watcher is associated with (or no additional members at all if |
|
|
1921 | you disable \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR when embedding libev). |
|
|
1922 | .PP |
|
|
1923 | Currently, functions, and static and non-static member functions can be |
|
|
1924 | used as callbacks. Other types should be easy to add as long as they only |
|
|
1925 | need one additional pointer for context. If you need support for other |
|
|
1926 | types of functors please contact the author (preferably after implementing |
|
|
1927 | it). |
1901 | .PP |
1928 | .PP |
1902 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
1929 | Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace: |
1903 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
1930 | .ie n .IP """ev::READ""\fR, \f(CW""ev::WRITE"" etc." 4 |
1904 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
1931 | .el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4 |
1905 | .IX Item "ev::READ, ev::WRITE etc." |
1932 | .IX Item "ev::READ, ev::WRITE etc." |
… | |
… | |
1917 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
1944 | which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro |
1918 | defines by many implementations. |
1945 | defines by many implementations. |
1919 | .Sp |
1946 | .Sp |
1920 | All of those classes have these methods: |
1947 | All of those classes have these methods: |
1921 | .RS 4 |
1948 | .RS 4 |
1922 | .IP "ev::TYPE::TYPE (object *, object::method *)" 4 |
1949 | .IP "ev::TYPE::TYPE ()" 4 |
1923 | .IX Item "ev::TYPE::TYPE (object *, object::method *)" |
1950 | .IX Item "ev::TYPE::TYPE ()" |
1924 | .PD 0 |
1951 | .PD 0 |
1925 | .IP "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" 4 |
1952 | .IP "ev::TYPE::TYPE (struct ev_loop *)" 4 |
1926 | .IX Item "ev::TYPE::TYPE (object *, object::method *, struct ev_loop *)" |
1953 | .IX Item "ev::TYPE::TYPE (struct ev_loop *)" |
1927 | .IP "ev::TYPE::~TYPE" 4 |
1954 | .IP "ev::TYPE::~TYPE" 4 |
1928 | .IX Item "ev::TYPE::~TYPE" |
1955 | .IX Item "ev::TYPE::~TYPE" |
1929 | .PD |
1956 | .PD |
1930 | The constructor takes a pointer to an object and a method pointer to |
1957 | The constructor (optionally) takes an event loop to associate the watcher |
1931 | the event handler callback to call in this class. The constructor calls |
1958 | with. If it is omitted, it will use \f(CW\*(C`EV_DEFAULT\*(C'\fR. |
1932 | \&\f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the \f(CW\*(C`set\*(C'\fR method |
1959 | .Sp |
1933 | before starting it. If you do not specify a loop then the constructor |
1960 | The constructor calls \f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the |
1934 | automatically associates the default loop with this watcher. |
1961 | \&\f(CW\*(C`set\*(C'\fR method before starting it. |
|
|
1962 | .Sp |
|
|
1963 | It will not set a callback, however: You have to call the templated \f(CW\*(C`set\*(C'\fR |
|
|
1964 | method to set a callback before you can start the watcher. |
|
|
1965 | .Sp |
|
|
1966 | (The reason why you have to use a method is a limitation in \*(C+ which does |
|
|
1967 | not allow explicit template arguments for constructors). |
1935 | .Sp |
1968 | .Sp |
1936 | The destructor automatically stops the watcher if it is active. |
1969 | The destructor automatically stops the watcher if it is active. |
|
|
1970 | .IP "w\->set<class, &class::method> (object *)" 4 |
|
|
1971 | .IX Item "w->set<class, &class::method> (object *)" |
|
|
1972 | This method sets the callback method to call. The method has to have a |
|
|
1973 | signature of \f(CW\*(C`void (*)(ev_TYPE &, int)\*(C'\fR, it receives the watcher as |
|
|
1974 | first argument and the \f(CW\*(C`revents\*(C'\fR as second. The object must be given as |
|
|
1975 | parameter and is stored in the \f(CW\*(C`data\*(C'\fR member of the watcher. |
|
|
1976 | .Sp |
|
|
1977 | This method synthesizes efficient thunking code to call your method from |
|
|
1978 | the C callback that libev requires. If your compiler can inline your |
|
|
1979 | callback (i.e. it is visible to it at the place of the \f(CW\*(C`set\*(C'\fR call and |
|
|
1980 | your compiler is good :), then the method will be fully inlined into the |
|
|
1981 | thunking function, making it as fast as a direct C callback. |
|
|
1982 | .Sp |
|
|
1983 | Example: simple class declaration and watcher initialisation |
|
|
1984 | .Sp |
|
|
1985 | .Vb 4 |
|
|
1986 | \& struct myclass |
|
|
1987 | \& { |
|
|
1988 | \& void io_cb (ev::io &w, int revents) { } |
|
|
1989 | \& } |
|
|
1990 | .Ve |
|
|
1991 | .Sp |
|
|
1992 | .Vb 3 |
|
|
1993 | \& myclass obj; |
|
|
1994 | \& ev::io iow; |
|
|
1995 | \& iow.set <myclass, &myclass::io_cb> (&obj); |
|
|
1996 | .Ve |
|
|
1997 | .IP "w\->set<function> (void *data = 0)" 4 |
|
|
1998 | .IX Item "w->set<function> (void *data = 0)" |
|
|
1999 | Also sets a callback, but uses a static method or plain function as |
|
|
2000 | callback. The optional \f(CW\*(C`data\*(C'\fR argument will be stored in the watcher's |
|
|
2001 | \&\f(CW\*(C`data\*(C'\fR member and is free for you to use. |
|
|
2002 | .Sp |
|
|
2003 | The prototype of the \f(CW\*(C`function\*(C'\fR must be \f(CW\*(C`void (*)(ev::TYPE &w, int)\*(C'\fR. |
|
|
2004 | .Sp |
|
|
2005 | See the method\-\f(CW\*(C`set\*(C'\fR above for more details. |
|
|
2006 | .Sp |
|
|
2007 | Example: |
|
|
2008 | .Sp |
|
|
2009 | .Vb 2 |
|
|
2010 | \& static void io_cb (ev::io &w, int revents) { } |
|
|
2011 | \& iow.set <io_cb> (); |
|
|
2012 | .Ve |
1937 | .IP "w\->set (struct ev_loop *)" 4 |
2013 | .IP "w\->set (struct ev_loop *)" 4 |
1938 | .IX Item "w->set (struct ev_loop *)" |
2014 | .IX Item "w->set (struct ev_loop *)" |
1939 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
2015 | Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only |
1940 | do this when the watcher is inactive (and not pending either). |
2016 | do this when the watcher is inactive (and not pending either). |
1941 | .IP "w\->set ([args])" 4 |
2017 | .IP "w\->set ([args])" 4 |
1942 | .IX Item "w->set ([args])" |
2018 | .IX Item "w->set ([args])" |
1943 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
2019 | Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR, with the same args. Must be |
1944 | called at least once. Unlike the C counterpart, an active watcher gets |
2020 | called at least once. Unlike the C counterpart, an active watcher gets |
1945 | automatically stopped and restarted. |
2021 | automatically stopped and restarted when reconfiguring it with this |
|
|
2022 | method. |
1946 | .IP "w\->start ()" 4 |
2023 | .IP "w\->start ()" 4 |
1947 | .IX Item "w->start ()" |
2024 | .IX Item "w->start ()" |
1948 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument as the |
2025 | Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the |
1949 | constructor already takes the loop. |
2026 | constructor already stores the event loop. |
1950 | .IP "w\->stop ()" 4 |
2027 | .IP "w\->stop ()" 4 |
1951 | .IX Item "w->stop ()" |
2028 | .IX Item "w->stop ()" |
1952 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
2029 | Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument. |
1953 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
2030 | .ie n .IP "w\->again () ""ev::timer""\fR, \f(CW""ev::periodic"" only" 4 |
1954 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
2031 | .el .IP "w\->again () \f(CWev::timer\fR, \f(CWev::periodic\fR only" 4 |
… | |
… | |
1980 | .Vb 2 |
2057 | .Vb 2 |
1981 | \& myclass (); |
2058 | \& myclass (); |
1982 | \& } |
2059 | \& } |
1983 | .Ve |
2060 | .Ve |
1984 | .PP |
2061 | .PP |
1985 | .Vb 6 |
2062 | .Vb 4 |
1986 | \& myclass::myclass (int fd) |
2063 | \& myclass::myclass (int fd) |
1987 | \& : io (this, &myclass::io_cb), |
|
|
1988 | \& idle (this, &myclass::idle_cb) |
|
|
1989 | \& { |
2064 | \& { |
|
|
2065 | \& io .set <myclass, &myclass::io_cb > (this); |
|
|
2066 | \& idle.set <myclass, &myclass::idle_cb> (this); |
|
|
2067 | .Ve |
|
|
2068 | .PP |
|
|
2069 | .Vb 2 |
1990 | \& io.start (fd, ev::READ); |
2070 | \& io.start (fd, ev::READ); |
1991 | \& } |
2071 | \& } |
1992 | .Ve |
2072 | .Ve |
1993 | .SH "MACRO MAGIC" |
2073 | .SH "MACRO MAGIC" |
1994 | .IX Header "MACRO MAGIC" |
2074 | .IX Header "MACRO MAGIC" |
1995 | Libev can be compiled with a variety of options, the most fundemantal is |
2075 | Libev can be compiled with a variety of options, the most fundemantal is |
1996 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines wether (most) functions and |
2076 | \&\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most) functions and |
1997 | callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
2077 | callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument. |
1998 | .PP |
2078 | .PP |
1999 | To make it easier to write programs that cope with either variant, the |
2079 | To make it easier to write programs that cope with either variant, the |
2000 | following macros are defined: |
2080 | following macros are defined: |
2001 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
2081 | .ie n .IP """EV_A""\fR, \f(CW""EV_A_""" 4 |
… | |
… | |
2037 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
2117 | .IX Item "EV_DEFAULT, EV_DEFAULT_" |
2038 | Similar to the other two macros, this gives you the value of the default |
2118 | Similar to the other two macros, this gives you the value of the default |
2039 | loop, if multiple loops are supported (\*(L"ev loop default\*(R"). |
2119 | loop, if multiple loops are supported (\*(L"ev loop default\*(R"). |
2040 | .PP |
2120 | .PP |
2041 | Example: Declare and initialise a check watcher, utilising the above |
2121 | Example: Declare and initialise a check watcher, utilising the above |
2042 | macros so it will work regardless of wether multiple loops are supported |
2122 | macros so it will work regardless of whether multiple loops are supported |
2043 | or not. |
2123 | or not. |
2044 | .PP |
2124 | .PP |
2045 | .Vb 5 |
2125 | .Vb 5 |
2046 | \& static void |
2126 | \& static void |
2047 | \& check_cb (EV_P_ ev_timer *w, int revents) |
2127 | \& check_cb (EV_P_ ev_timer *w, int revents) |
… | |
… | |
2274 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
2354 | If undefined or defined to \f(CW1\fR, then all event-loop-specific functions |
2275 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
2355 | will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create |
2276 | additional independent event loops. Otherwise there will be no support |
2356 | additional independent event loops. Otherwise there will be no support |
2277 | for multiple event loops and there is no first event loop pointer |
2357 | for multiple event loops and there is no first event loop pointer |
2278 | argument. Instead, all functions act on the single default loop. |
2358 | argument. Instead, all functions act on the single default loop. |
|
|
2359 | .IP "\s-1EV_MINPRI\s0" 4 |
|
|
2360 | .IX Item "EV_MINPRI" |
|
|
2361 | .PD 0 |
|
|
2362 | .IP "\s-1EV_MAXPRI\s0" 4 |
|
|
2363 | .IX Item "EV_MAXPRI" |
|
|
2364 | .PD |
|
|
2365 | The range of allowed priorities. \f(CW\*(C`EV_MINPRI\*(C'\fR must be smaller or equal to |
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2366 | \&\f(CW\*(C`EV_MAXPRI\*(C'\fR, but otherwise there are no non-obvious limitations. You can |
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2367 | provide for more priorities by overriding those symbols (usually defined |
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2368 | to be \f(CW\*(C`\-2\*(C'\fR and \f(CW2\fR, respectively). |
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2369 | .Sp |
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2370 | When doing priority-based operations, libev usually has to linearly search |
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2371 | all the priorities, so having many of them (hundreds) uses a lot of space |
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2372 | and time, so using the defaults of five priorities (\-2 .. +2) is usually |
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2373 | fine. |
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2374 | .Sp |
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2375 | If your embedding app does not need any priorities, defining these both to |
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2376 | \&\f(CW0\fR will save some memory and cpu. |
2279 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
2377 | .IP "\s-1EV_PERIODIC_ENABLE\s0" 4 |
2280 | .IX Item "EV_PERIODIC_ENABLE" |
2378 | .IX Item "EV_PERIODIC_ENABLE" |
2281 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
2379 | If undefined or defined to be \f(CW1\fR, then periodic timers are supported. If |
2282 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
2380 | defined to be \f(CW0\fR, then they are not. Disabling them saves a few kB of |
2283 | code. |
2381 | code. |
… | |
… | |
2382 | .SH "COMPLEXITIES" |
2480 | .SH "COMPLEXITIES" |
2383 | .IX Header "COMPLEXITIES" |
2481 | .IX Header "COMPLEXITIES" |
2384 | In this section the complexities of (many of) the algorithms used inside |
2482 | In this section the complexities of (many of) the algorithms used inside |
2385 | libev will be explained. For complexity discussions about backends see the |
2483 | libev will be explained. For complexity discussions about backends see the |
2386 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
2484 | documentation for \f(CW\*(C`ev_default_init\*(C'\fR. |
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2485 | .Sp |
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2486 | All of the following are about amortised time: If an array needs to be |
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2487 | extended, libev needs to realloc and move the whole array, but this |
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2488 | happens asymptotically never with higher number of elements, so O(1) might |
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2489 | mean it might do a lengthy realloc operation in rare cases, but on average |
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2490 | it is much faster and asymptotically approaches constant time. |
2387 | .RS 4 |
2491 | .RS 4 |
2388 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
2492 | .IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4 |
2389 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
2493 | .IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" |
2390 | .PD 0 |
2494 | This means that, when you have a watcher that triggers in one hour and |
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2495 | there are 100 watchers that would trigger before that then inserting will |
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2496 | have to skip those 100 watchers. |
2391 | .IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4 |
2497 | .IP "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" 4 |
2392 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
2498 | .IX Item "Changing timer/periodic watchers (by autorepeat, again): O(log skipped_other_timers)" |
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2499 | That means that for changing a timer costs less than removing/adding them |
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2500 | as only the relative motion in the event queue has to be paid for. |
2393 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
2501 | .IP "Starting io/check/prepare/idle/signal/child watchers: O(1)" 4 |
2394 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
2502 | .IX Item "Starting io/check/prepare/idle/signal/child watchers: O(1)" |
2395 | .IP "Stopping check/prepare/idle watchers: O(1)" 4 |
2503 | These just add the watcher into an array or at the head of a list. |
2396 | .IX Item "Stopping check/prepare/idle watchers: O(1)" |
2504 | =item Stopping check/prepare/idle watchers: O(1) |
2397 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4 |
2505 | .IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4 |
2398 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))" |
2506 | .IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))" |
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2507 | These watchers are stored in lists then need to be walked to find the |
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2508 | correct watcher to remove. The lists are usually short (you don't usually |
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2509 | have many watchers waiting for the same fd or signal). |
2399 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
2510 | .IP "Finding the next timer per loop iteration: O(1)" 4 |
2400 | .IX Item "Finding the next timer per loop iteration: O(1)" |
2511 | .IX Item "Finding the next timer per loop iteration: O(1)" |
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|
2512 | .PD 0 |
2401 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
2513 | .IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4 |
2402 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
2514 | .IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" |
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2515 | .PD |
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2516 | A change means an I/O watcher gets started or stopped, which requires |
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2517 | libev to recalculate its status (and possibly tell the kernel). |
2403 | .IP "Activating one watcher: O(1)" 4 |
2518 | .IP "Activating one watcher: O(1)" 4 |
2404 | .IX Item "Activating one watcher: O(1)" |
2519 | .IX Item "Activating one watcher: O(1)" |
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2520 | .PD 0 |
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2521 | .IP "Priority handling: O(number_of_priorities)" 4 |
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2522 | .IX Item "Priority handling: O(number_of_priorities)" |
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2523 | .PD |
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2524 | Priorities are implemented by allocating some space for each |
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2525 | priority. When doing priority-based operations, libev usually has to |
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2526 | linearly search all the priorities. |
2405 | .RE |
2527 | .RE |
2406 | .RS 4 |
2528 | .RS 4 |
2407 | .PD |
|
|
2408 | .SH "AUTHOR" |
2529 | .SH "AUTHOR" |
2409 | .IX Header "AUTHOR" |
2530 | .IX Header "AUTHOR" |
2410 | Marc Lehmann <libev@schmorp.de>. |
2531 | Marc Lehmann <libev@schmorp.de>. |