1 Linux 安装 Libevent

Posted 2020-08-22

Libevent官网:http://libevent.org/

在线文档:http://www.wangafu.net/~nickm/libevent-2.0/doxygen/html/

下载地址:https://github.com/libevent/libevent/releases/

解压,编译,安装

创建文件夹
[email protected]:~$ mkdir libevent
[email protected]:~$ cd libevent/

解压文件:
[email protected]:~/libevent$ tar xf libevent-2.0.22-stable.tar.gz 
[email protected]:~/libevent$ cd libevent-2.0.22-stable/

编译环境检查:
[email protected]:~/libevent/libevent-2.0.22-stable$ ./configure 
[email protected]:~/libevent/libevent-2.0.22-stable$ echo $?
0

编译:
[email protected]:~/libevent/libevent-2.0.22-stable$ make -j 8
[email protected]:~/libevent/libevent-2.0.22-stable$ echo $?
0

安装:
[email protected]:~/libevent/libevent-2.0.22-stable$ sudo make install 
[email protected]:~/libevent/libevent-2.0.22-stable$ echo $?
0

删除临时文件:
[email protected]:~$ cd libevent/libevent-2.0.22-stable/
[email protected]:~/libevent/libevent-2.0.22-stable$ cd ..
[email protected]:~/libevent$ rm -rf libevent-2.0.22-stable
[email protected]:~/libevent$ echo $?
0

测试程序:

[email protected]:~/libevent$ cat hello-world.c 
/*
  This exmple program provides a trivial server program that listens for TCP
  connections on port 9995.  When they arrive, it writes a short message to
  each client connection, and closes each connection once it is flushed.

  Where possible, it exits cleanly in response to a SIGINT (ctrl-c).
*/


#include <string.h>
#include <errno.h>
#include <stdio.h>
#include <signal.h>
#ifndef WIN32
#include <netinet/in.h>
# ifdef _XOPEN_SOURCE_EXTENDED
#  include <arpa/inet.h>
# endif
#include <sys/socket.h>
#endif

#include <event2/bufferevent.h>
#include <event2/buffer.h>
#include <event2/listener.h>
#include <event2/util.h>
#include <event2/event.h>

static const char MESSAGE[] = "Hello, World!\n";

static const int PORT = 9995;

static void listener_cb(struct evconnlistener *, evutil_socket_t,
    struct sockaddr *, int socklen, void *);
static void conn_writecb(struct bufferevent *, void *);
static void conn_eventcb(struct bufferevent *, short, void *);
static void signal_cb(evutil_socket_t, short, void *);

int
main(int argc, char **argv)
{
	struct event_base *base;
	struct evconnlistener *listener;
	struct event *signal_event;

	struct sockaddr_in sin;
#ifdef WIN32
	WSADATA wsa_data;
	WSAStartup(0x0201, &wsa_data);
#endif

	base = event_base_new();
	if (!base) {
		fprintf(stderr, "Could not initialize libevent!\n");
		return 1;
	}

	memset(&sin, 0, sizeof(sin));
	sin.sin_family = AF_INET;
	sin.sin_port = htons(PORT);

	listener = evconnlistener_new_bind(base, listener_cb, (void *)base,
	    LEV_OPT_REUSEABLE|LEV_OPT_CLOSE_ON_FREE, -1,
	    (struct sockaddr*)&sin,
	    sizeof(sin));

	if (!listener) {
		fprintf(stderr, "Could not create a listener!\n");
		return 1;
	}

	signal_event = evsignal_new(base, SIGINT, signal_cb, (void *)base);

	if (!signal_event || event_add(signal_event, NULL)<0) {
		fprintf(stderr, "Could not create/add a signal event!\n");
		return 1;
	}

	event_base_dispatch(base);

	evconnlistener_free(listener);
	event_free(signal_event);
	event_base_free(base);

	printf("done\n");
	return 0;
}

static void
listener_cb(struct evconnlistener *listener, evutil_socket_t fd,
    struct sockaddr *sa, int socklen, void *user_data)
{
	struct event_base *base = user_data;
	struct bufferevent *bev;

	bev = bufferevent_socket_new(base, fd, BEV_OPT_CLOSE_ON_FREE);
	if (!bev) {
		fprintf(stderr, "Error constructing bufferevent!");
		event_base_loopbreak(base);
		return;
	}
	bufferevent_setcb(bev, NULL, conn_writecb, conn_eventcb, NULL);
	bufferevent_enable(bev, EV_WRITE);
	bufferevent_disable(bev, EV_READ);

	bufferevent_write(bev, MESSAGE, strlen(MESSAGE));
}

static void
conn_writecb(struct bufferevent *bev, void *user_data)
{
	struct evbuffer *output = bufferevent_get_output(bev);
	if (evbuffer_get_length(output) == 0) {
		printf("flushed answer\n");
		bufferevent_free(bev);
	}
}

static void
conn_eventcb(struct bufferevent *bev, short events, void *user_data)
{
	if (events & BEV_EVENT_EOF) {
		printf("Connection closed.\n");
	} else if (events & BEV_EVENT_ERROR) {
		printf("Got an error on the connection: %s\n",
		    strerror(errno));/*XXX win32*/
	}
	/* None of the other events can happen here, since we haven‘t enabled
	 * timeouts */
	bufferevent_free(bev);
}

static void
signal_cb(evutil_socket_t sig, short events, void *user_data)
{
	struct event_base *base = user_data;
	struct timeval delay = { 2, 0 };

	printf("Caught an interrupt signal; exiting cleanly in two seconds.\n");

	event_base_loopexit(base, &delay);
}



编译运行:
[email protected]:~/libevent$ gcc hello-world.c -l event -Wall  && ./a.out 



查看端口监听:
[email protected]:~$ sudo netstat -tanlp | grep a.out
tcp        0      0 0.0.0.0:9995            0.0.0.0:*               LISTEN      7740/a.out      


本机IP
[email protected]:~$ ifconfig eth0
eth0      Link encap:以太网  硬件地址 00:0c:29:c8:7a:35  
          inet 地址:11.11.11.5  广播:11.11.11.255  掩码:255.255.255.0

----------------------------------








局域网其他机子访问测试:
[email protected]:~ $ nc 11.11.11.5 9995
Hello, World!
[email protected]:~ $ nc 11.11.11.5 9995
Hello, World!

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