与天地兮比寿，与日月兮齐光。这篇文章主要讲述Visual Studio 2017开发linux程序之libevent使用实例相关的知识，希望能为你提供帮助。
下载源码编译安装后，samle里面有个hello-world.c就是最简单的一个tcp server端程序了

/*
This example 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 havent 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);