ubuntu下载安装libevent

ubuntu下载安装libevent

1. libevent 官网上下载最新稳定版本，然后拖到你的linux系统中，解压。或者可是使用wget在线下载。本文下载的是最新版本，其他版本同操作

2. tar xf libevent-2.1.12-stable.tar.gz 
   

3. 进入解压后的目录，执行

   ./configure 
   

   可能会出现报错，内容如下：

   checking for library containing SSL_new... no
   checking for library containing SSL_new... no
   checking openssl/ssl.h usability... no
   checking openssl/ssl.h presence... no
   checking for openssl/ssl.h... no
   configure: error: openssl is a must but can not be found. You should add the directory containing `openssl.pc' to the `PKG_CONFIG_PATH' environment variable, or set `CFLAGS' and `LDFLAGS' directly for openssl, or use `--disable-openssl' to disable support for openssl encryption
   

   解决办法安装libssl-dev

   sudo apt install libssl-dev
   

4. 安装

   make 
   sudo make install
   

5. 查看安装成功否

   ls /usr/local/lib/libevent*
   

   若出现下面的文件，则安装成功。

   ls /usr/local/lib/libevent*
   /usr/local/lib/libevent-2.1.so.7            /usr/local/lib/libevent_extra.la
   /usr/local/lib/libevent-2.1.so.7.0.1        /usr/local/lib/libevent_extra.so
   /usr/local/lib/libevent.a                   /usr/local/lib/libevent_openssl-2.1.so.7
   /usr/local/lib/libevent.la                  /usr/local/lib/libevent_openssl-2.1.so.7.0.1
   /usr/local/lib/libevent.so                  /usr/local/lib/libevent_openssl.a
   /usr/local/lib/libevent_core-2.1.so.7       /usr/local/lib/libevent_openssl.la
   /usr/local/lib/libevent_core-2.1.so.7.0.1   /usr/local/lib/libevent_openssl.so
   /usr/local/lib/libevent_core.a              /usr/local/lib/libevent_pthreads-2.1.so.7
   /usr/local/lib/libevent_core.la             /usr/local/lib/libevent_pthreads-2.1.so.7.0.1
   /usr/local/lib/libevent_core.so             /usr/local/lib/libevent_pthreads.a
   /usr/local/lib/libevent_extra-2.1.so.7      /usr/local/lib/libevent_pthreads.la
   /usr/local/lib/libevent_extra-2.1.so.7.0.1  /usr/local/lib/libevent_pthreads.so
   /usr/local/lib/libevent_extra.a
   

6. 编译的时候加-levent选项

7. 代码示例：

   // 信号事件
   void signal_cb(int fd, short event, void *arg)
   {
       printf("SIGINT is comming! if you wang exit process, please enter other signal\n");
   }
   
   // 定时事件
   void time_cb(int fd, short event, void *arg)
   {
       printf("time out\n");
       exit(0);
   }
   
   int main()
   {
       struct event_base *base = event_init(); // base为Libevent的一个实例,对base进行初始化
   
       // 创建信号事件
       struct event *signal_event = evsignal_new(base, SIGINT, signal_cb, NULL);
       event_add(signal_event, NULL); // 将事件注册到Libevent中
   
       // 创建定时事件
       timeval tm{5}; // 定时时间5s
       struct event *time_event = evtimer_new(base, time_cb, NULL);
       event_add(time_event, &tm); // 将事件注册到Libevent中
   
       // 执行事件循环,检测就绪事件
       event_base_dispatch(base);
   
       // 事件循环结束,释放资源
       event_free(signal_event);
       event_free(time_event);
       event_base_free(base);
   
       return 0;
   }
   

   上述程序，捕捉2号信号，并设置捕捉超时时间5秒。