NOTE: Incompatible failure mode changes in v2.0 compared to v1.x!
libuEv is a simple event loop in the style of the more established libevent, libev and the venerable Xt(3) event loop. The u (micro) in the name refers to both the small feature set and the small size overhead impact of the library.
Failure mode changes introduced in v2.0 may affect users of v1.x, See the ChangeLog for the full details.
The API documentation is available as a separate document.
Notice below how watcher UEV_ERROR
conditions must be handled by each
callback. I/O watchers must also check for UEV_HUP
. Both errors are
usually fatal, libuEv makes sure to stop each watcher before a callback
runs, leaving it up to the callback to take appropriate action.
#include <stdio.h>
#include <uev/uev.h>
static void cb(uev_t *w, void *arg, int events)
{
if (UEV_ERROR == events) {
puts("Problem with timer, attempting to restart.");
uev_timer_start(w);
}
puts("Every other second");
}
int main(void)
{
uev_t timer;
uev_ctx_t ctx;
uev_init(&ctx);
/* Set up a timer watcher to call cb() every other second */
uev_timer_init(&ctx, &timer, cb, NULL, 2 * 1000, 2 * 1000);
return uev_run(&ctx, 0);
}
libuEv use the GNU configure and build system. To try out the bundled
examples, use the --enable-examples
switch to the configure
script.
There is also a limited unit test suite that can be useful to learn how
the library works.
./configure
make -j5
make test
sudo make install-strip
sudo ldconfig
The resulting .so file is ~14 kiB.
libuEv originates from LibUEvent by Flemming Madsen, but with a rewritten and much cleaner API. It is now more similar to the famous libev by Mark Lehmann. Another library inspiring this project is picoev by Oku Kazuho.
libuEv is developed and maintained by Joachim Nilsson. It is built for and developed on GNU/Linux systems, patches to support *BSD and its kqueue interface are most welcome.