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https://github.com/troglobit/pev
Portable Event Library
https://github.com/troglobit/pev
bsd event-driven event-library linux portable portable-library public-domain signals socket-io sockets timers unix
Last synced: 16 days ago
JSON representation
Portable Event Library
- Host: GitHub
- URL: https://github.com/troglobit/pev
- Owner: troglobit
- License: unlicense
- Created: 2020-11-14T13:16:26.000Z (almost 4 years ago)
- Default Branch: main
- Last Pushed: 2024-10-20T17:33:49.000Z (23 days ago)
- Last Synced: 2024-10-21T22:13:14.404Z (22 days ago)
- Topics: bsd, event-driven, event-library, linux, portable, portable-library, public-domain, signals, socket-io, sockets, timers, unix
- Language: C
- Homepage:
- Size: 60.5 KB
- Stars: 15
- Watchers: 4
- Forks: 2
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: ChangeLog.md
Awesome Lists containing this project
README
Portable Event Library (PEV)
============================
[![License Badge][]][License] [![GitHub Status][]][GitHub] [![Coverity Status][]][Coverity Scan]
This is a small event library in C based around `select()` available
free for use in the [*public domain*](UNLICENSE).
Upgrade Warnings
----------------
Heads-up, breaking changes in these versions!
* v1.3 changes timer resolution from 1 second to 1 microsecond
* v1.5 changes timer API to add support for one-shot timers
* v2.0 timer callbacks now get `id` as first argument, not timeout
See [ChangeLog](ChangeLog.md) for details.
The Code
--------
The event loop consists of two files: `pev.c` and `pev.h`. You can use
it as a library or just include the components into your own project.
See the header file for the API description. If you find bugs or have
fixes to share, please report them using [GitHub issues][] or, preferably,
[pull requests][].
Example
-------
```C
#include
#include
#include "pev.h"
#define TIMEOUT 500000 /* 0.5 sec */
int id;
static void cb(int timeout, void *arg)
{
printf("Hej %d\n", timeout);
pev_timer_set(id, timeout + TIMEOUT);
}
static void br(int signo, void *arg)
{
pev_exit(10);
}
int main(void)
{
pev_init();
pev_sig_add(SIGINT, br, NULL);
id = pev_timer_add(TIMEOUT, 0, cb, NULL);
return pev_run();
}
```
Gives the following output:
```sh
$ gcc -I. -o example example.c pev.c
$ ./example
Hej 500000
Hej 1000000
Hej 1500000
Hej 2000000
Hej 2500000
^C
```
Implementation Notes
--------------------
**Note:** The timer implementation uses `setitimer()` for maximum
portability. Depending on the system, this can potentially cause
problems if your application also use `sleep()`, `usleep()`, or
`alarm()`, which may all use the same back end implantation in your
operating system. Please check the documentation for your OS for
more information on the subject.
Building and Testing
--------------------
For those that don't just take the sources and integrate into their own
project. You may have to set `CC`, to install you must set `prefix`.
Example:
make clean
make CC=clang
make install prefix=/usr/local
...
make uninstall prefix=/usr/local
History and Background
----------------------
The design evolved over time in the [SMCRoute][] project, where I wanted
to keep the tool small and with as few (no) external dependencies as
possible.
It started out as a refactor of the socket polling functionality, and
really came into its own in 2017 when I found Mr Rich Felker's mention
of the classic [timer-to-pipe pattern][1] on Stack Overflow.
In the years passed I've noticed many times the need for a really small
and, most importantly, *portable* event loop. So here's the code I
wrote for SMCRoute, cleaned up and now fully free in the public domain.
Take care!
/Joachim :-)
[1]: https://stackoverflow.com/questions/2328127/select-able-timers/6800676#6800676
[SMCRoute]: https://github.com/troglobit/SMCRoute
[GitHub issues]: https://github.com/troglobit/pev/issues
[pull requests]: https://github.com/troglobit/pev/pulls
[License]: https://unlicense.org/
[License Badge]: https://img.shields.io/badge/License-Unlicense-blue.svg
[GitHub]: https://github.com/troglobit/pev/actions/workflows/build.yml/
[GitHub Status]: https://github.com/troglobit/pev/actions/workflows/build.yml/badge.svg
[Coverity Scan]: https://scan.coverity.com/projects/30840
[Coverity Status]: https://scan.coverity.com/projects/30840/badge.svg