Libevent使用

一、简介

Libevent 是一个用C语言编写的、轻量级的开源高性能网络库，主要特点：

1、事件驱动，即异步调用

2、支持多种 I/O多路复用技术， epoll、poll、dev/poll、select 和kqueue 等。

地址在 http://libevent.org/ 可在该网站下载最新的代码库。

The libevent API provides a mechanism to execute a callback function when a specific event occurs on a file descriptor or after a timeout has been reached. Furthermore, libevent also support callbacks due to signals or regular timeouts.

 

二、安装

下载libevent-1.4.14b-stable.tar.gz，执行以下操作

tar –xzvf libevent-1.4.14b-stable.tar.gz

cd libevent-1.4.14b-stable

./configure --prefix=/usr/local/libevent

make

make install

root@ubuntu:memcached# whereis libevent
libevent: /usr/local/libevent

 

三、使用

1、简单的定时器程序

#include <iostream>
#include <event.h>
#include <stdio.h>

using namespace std;

struct event timer;
struct timeval tv; 
static char data[0x100] = "hello, mamoyang!\n";

void say_hello(int fd, short event, void* arg)
{
    printf("%d, %d, %s", fd, event, (char* )arg);
    evtimer_add(&timer, &tv);
}

int main(void)
{
    event_init();
    evtimer_set(&timer, say_hello, data);
    tv.tv_sec = 2;
    tv.tv_usec = 0;
    evtimer_add(&timer, &tv);

    event_dispatch();
    return 0;
}

Makefile如下：

TARG=timer

all: $(TARG)

CFLAGS= -g -O0 -I /usr/local/libevent/include
LDFLAGS= -L /usr/local/libevent/lib -levent


$(TARG) : $(TARG).cpp
    g++ $(CFLAGS) $< -o $@ $(LDFLAGS)

clean:
    rm -rf $(TARG)

root@ubuntu:timer# ./timer
-1, 1, hello, mamoyang!
-1, 1, hello, mamoyang!