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