Joachim Nilsson
2f9cce9150
This patch fixes a blocking issue discovered in the Finit project. At shutdown, or when there is any problem with a timer or signal watcher, the event loop is abruptly terminated. Instead of unconditionally exiting the event loop on problems with a single watcher, invalidate the watcher and run the callback one last time with UEV_ERROR in the events argument. This is a semantic change wrt. watchers and their callbacks, so the major version number will be bumped accordingly to signal the severity of this change. From now on it is STRONGLY recommended that each call back function check for UEV_ERROR. Signed-off-by: Joachim Nilsson <troglobit@gmail.com>
libuEv | Simple event loop for Linux
“Event driven software improves concurrency” -- Dave Zarzycki, Apple
Introduction
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.
Experienced developers may appreciate that libuEv is built on top of modern Linux APIs: epoll, timerfd and signalfd.
Example
The library documentation is available as a separate document.
#include <stdio.h>
#include <uev/uev.h>
static void cb(uev_t *w, void *arg, int events)
{
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, 0, 2 * 1000);
return uev_run(&ctx, 0);
}
Build & Install
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.
Origin & References
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.