Libevent示例程序4 信号量

#include <sys/types.h>

#include <sys/stat.h>

#include <sys/queue.h>
#include <unistd.h>
#include <sys/time.h>


#include <signal.h>
#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>

//
#include <event.h>


int called = 0;

static void
signal_cb(evutil_socket_t fd, short event, void *arg)
{
	struct event *signal = arg;

	printf("got signal.\n");

    // 如果用户取消两次，这时删除改事件
	if (called >= 2)
		event_del(signal);

	called++;
}

int
main(int argc, char **argv)
{
	struct event signal_int;
	struct event_base* base;

	/* Initalize the event library */
	base = event_base_new();

	/* Initalize one event */
	event_assign(&signal_int, base, SIGINT, EV_SIGNAL|EV_PERSIST, signal_cb,
	    &signal_int);

	event_add(&signal_int, NULL);

	event_base_dispatch(base);

	/*
        如果一个event_base对象不再使用的话，可以调用
        改函数删除event_base，但是这里需要注意的时event_base
        并不删除和event_base相关联的event对象，也不删除
        打开的其他资源
     */
	event_base_free(base);

	return (0);
}

shenhuayu@shenhuayu-VirtualBox ~/libevent $ gcc test.c -g -o mytest -levent
shenhuayu@shenhuayu-VirtualBox ~/libevent $ ./mytest
^Cgot signal.
^Cgot signal.
^Cgot signal.

from http://blog.csdn.net/xuqianghit/article/details/6640920