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EMBEDDING THE LIBEV CODE INTO YOUR OWN PROGRAMS |
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|
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Instead of building the libev library you can also include the code |
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as-is into your programs. To update, you only have to copy a few files |
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into your source tree. |
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|
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This is how it works: |
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|
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FILESETS |
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|
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CORE EVENT LOOP |
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|
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To include only the libev core (all the ev_* functions): |
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|
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#define EV_STANDALONE 1 |
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#include "ev.c" |
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|
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This will automatically include ev.h, too, and should be done in a |
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single C source file only to provide the function implementations. To |
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use it, do the same for ev.h in all files wishing to use this API |
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(best done by writing a wrapper around ev.h that you can include |
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instead and where you can put other configuration options): |
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|
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#define EV_STANDALONE 1 |
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#include "ev.h" |
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|
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Both header files and implementation files can be compiled with a C++ |
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compiler (at least, thats a stated goal, and breakage will be treated |
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as a bug). |
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|
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You need the following files in your source tree, or in a directory |
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in your include path (e.g. in libev/ when using -Ilibev): |
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|
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ev.h |
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ev.c |
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ev_vars.h |
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ev_wrap.h |
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|
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ev_win32.c required on win32 platforms only |
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|
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ev_select.c only when select backend is enabled (which is is by default) |
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ev_poll.c only when poll backend is enabled (disabled by default) |
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ev_epoll.c only when the epoll backend is enabled (disabled by default) |
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ev_kqueue.c only when the kqueue backend is enabled (disabled by default) |
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ev_port.c only when the solaris port backend is enabled (disabled by default) |
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|
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"ev.c" includes the backend files directly when enabled. |
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|
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LIBEVENT COMPATIBILITY API |
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|
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To include the libevent compatibility API, also include: |
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|
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#include "event.c" |
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|
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in the file including "ev.c", and: |
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|
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#include "event.h" |
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|
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in the files that want to use the libevent API. This also includes "ev.h". |
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|
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You need the following additional files for this: |
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|
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event.h |
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event.c |
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|
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AUTOCONF SUPPORT |
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|
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Instead of using EV_STANDALONE=1 and providing your config in whatever |
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way you want, you can also m4_include([libev.m4]) in your configure.ac |
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and leave EV_STANDALONE off. ev.c will then include "config.h" and |
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configure itself accordingly. |
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|
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PREPROCESSOR SYMBOLS |
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|
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Libev can be configured via a variety of preprocessor symbols you have to define |
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before including any of its files. The default is not to build for multiplicity |
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and only include the select backend. |
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|
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EV_STANDALONE |
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|
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Must always be "1", which keeps libev from including config.h or |
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other files, and it also defines dummy implementations for some |
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libevent functions (such as logging, which is not supported). It |
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will also not define any of the structs usually found in "event.h" |
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that are not directly supported by libev code alone. |
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|
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EV_USE_MONOTONIC |
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|
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If defined to be "1", libev will try to detect the availability |
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of the monotonic clock option at both compiletime and |
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runtime. Otherwise no use of the monotonic clock option will be |
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attempted. If you enable this, you usually have to link against |
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librt or something similar. Enabling it when the functionality |
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isn't available is safe, though. |
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|
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EV_USE_REALTIME |
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|
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If defined to be "1", libev will try to detect the availability |
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of the realtime clock option at compiletime (and assume its |
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availability at runtime if successful). Otherwise no use of the |
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realtime clock option will be attempted. This effectively replaces |
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gettimeofday by clock_get (CLOCK_REALTIME, ...) and will not normally |
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affect correctness. |
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|
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EV_USE_SELECT |
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|
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If undefined or defined to be "1", libev will compile in support |
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for the select(2) backend. No attempt at autodetection will be |
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done: if no other method takes over, select will be it. Otherwise |
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the select backend will not be compiled in. |
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|
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EV_SELECT_USE_FD_SET |
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|
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If defined to 1, then the select backend will use the system fd_set |
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structure. This is useful if libev doesn't compile due to a missing |
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NFDBITS or fd_mask definition or it misguesses the bitset layout on |
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exotic systems. This usually limits the range of file descriptors |
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to some low limit such as 1024 or might have other limitations |
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(winsocket only allows 64 sockets). The FD_SETSIZE macro, set |
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before compilation, might influence the size of the fd_set used. |
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|
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EV_SELECT_IS_WINSOCKET |
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|
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When defined to 1, the select backend will assume that |
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select/socket/connect etc. don't understand file descriptors but |
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wants osf handles on win32 (this is the case when the select to |
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be used is the winsock select). This means that it will call |
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_get_osfhandle on the fd to convert it to an OS handle. Otherwise, |
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it is assumed that all these functions actually work on fds, even |
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on win32. Should not be defined on non-win32 platforms. |
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|
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EV_USE_POLL |
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|
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If defined to be "1", libev will compile in support for the poll(2) |
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backend. Otherwise it will be enabled on non-win32 platforms. It |
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takes precedence over select. |
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|
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EV_USE_EPOLL |
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|
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If defined to be "1", libev will compile in support for the Linux |
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epoll backend. Its availability will be detected at runtime, |
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otherwise another method will be used as fallback. This is the |
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preferred backend for GNU/Linux systems. |
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|
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EV_USE_KQUEUE |
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|
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If defined to be "1", libev will compile in support for the BSD |
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style kqueue backend. Its availability will be detected at runtime, |
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otherwise another method will be used as fallback. This is the |
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preferred backend for BSD and BSD-like systems. Darwin brokenness |
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will be detected at runtime and routed around by disabling this |
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backend. |
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|
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EV_USE_PORT |
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|
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If defined to be "1", libev will compile in support for the Solaris |
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10 port style backend. Its availability will be detected at runtime, |
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otherwise another method will be used as fallback. This is the |
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preferred backend for Solaris 10 systems. |
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|
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EV_USE_DEVPOLL |
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|
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reserved for future expansion, works like the USE symbols above. |
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|
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EV_H |
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|
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The name of the ev.h header file used to include it. The default |
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if undefined is <ev.h> in event.h and "ev.h" in ev.c. This can |
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be used to virtually rename the ev.h header file in case of |
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conflicts. |
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|
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EV_EVENT_H |
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|
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Similarly to EV_H, this macro cna be used to override event.c's idea |
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of how the event.h header can be found. |
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|
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EV_PROTOTYPES |
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|
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If defined to be "0", then "ev.h" will not define any function |
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prototypes, but still define all the structs and other |
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symbols. This is occasionally useful. |
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|
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EV_MULTIPLICITY |
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|
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If undefined or defined to "1", then all event-loop-specific |
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functions will have the "struct ev_loop *" as first argument, and |
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you can create additional independent event loops. Otherwise there |
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will be no support for multiple event loops and there is no first |
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event loop pointer argument. Instead, all functions act on the |
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single default loop. |
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|
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EV_PERIODICS |
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|
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If undefined or defined to be "1", then periodic timers are |
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supported, otherwise not. This saves a few kb of code. |
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|
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EV_COMMON |
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|
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By default, all watchers have a "void *data" member. By redefining |
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this macro to a something else you can include more and other types |
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of members. You have to define it each time you include one of the |
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files, though, and it must be identical each time. |
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|
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For example, the perl EV module uses this: |
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|
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#define EV_COMMON \ |
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SV *self; /* contains this struct */ \ |
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SV *cb_sv, *fh /* note no trailing ";" */ |
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|
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EV_CB_DECLARE(type) |
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EV_CB_INVOKE(watcher,revents) |
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ev_set_cb(ev,cb) |
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|
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Can be used to change the callback member declaration in each |
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watcher, and the way callbacks are invoked and set. Must expand |
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to a struct member definition and a statement, respectively. See |
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the ev.v header file for their default definitions. One possible |
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use for overriding these is to avoid the ev_loop pointer as first |
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argument in all cases, or to use method calls instead of plain |
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function calls in C++. |
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|
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EXAMPLES |
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|
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For a real-world example of a program the includes libev |
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verbatim, you can have a look at the EV perl module |
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(http://software.schmorp.de/pkg/EV.html). It has the libev files in |
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the libev/ subdirectory and includes them in the EV/EVAPI.h (public |
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interface) and EV.xs (implementation) files. Only the EV.xs file will |
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be compiled. |
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|