2 This exmple program provides a trivial server program that listens for TCP
3 connections on port 9995. When they arrive, it writes a short message to
4 each client connection, and closes each connection once it is flushed.
6 Where possible, it exits cleanly in response to a SIGINT (ctrl-c).
15 #include <netinet/in.h>
16 #include <sys/socket.h>
19 #include <event2/bufferevent.h>
20 #include <event2/buffer.h>
21 #include <event2/listener.h>
22 #include <event2/util.h>
23 #include <event2/event.h>
25 static const char MESSAGE[] = "Hello, World!\n";
27 static const int PORT = 9995;
29 static void listener_cb(struct evconnlistener *, evutil_socket_t,
30 struct sockaddr *, int socklen, void *);
31 static void conn_writecb(struct bufferevent *, void *);
32 static void conn_eventcb(struct bufferevent *, short, void *);
33 static void signal_cb(evutil_socket_t, short, void *);
36 main(int argc, char **argv)
38 struct event_base *base;
39 struct evconnlistener *listener;
40 struct event *signal_event;
42 struct sockaddr_in sin;
45 WSAStartup(0x0201, &wsa_data);
48 base = event_base_new();
50 fprintf(stderr, "Could not initialize libevent!\n");
54 memset(&sin, 0, sizeof(sin));
55 sin.sin_family = AF_INET;
56 sin.sin_port = htons(PORT);
58 listener = evconnlistener_new_bind(base, listener_cb, (void *)base,
59 LEV_OPT_REUSEABLE|LEV_OPT_CLOSE_ON_FREE, -1,
60 (struct sockaddr*)&sin,
64 fprintf(stderr, "Could not create a listener!\n");
68 signal_event = evsignal_new(base, SIGINT, signal_cb, (void *)base);
70 if (!signal_event || event_add(signal_event, NULL)<0) {
71 fprintf(stderr, "Could not create/add a signal event!\n");
75 event_base_dispatch(base);
77 evconnlistener_free(listener);
78 event_free(signal_event);
79 event_base_free(base);
86 listener_cb(struct evconnlistener *listener, evutil_socket_t fd,
87 struct sockaddr *sa, int socklen, void *user_data)
89 struct event_base *base = user_data;
90 struct bufferevent *bev;
92 bev = bufferevent_socket_new(base, fd, BEV_OPT_CLOSE_ON_FREE);
94 fprintf(stderr, "Error constructing bufferevent!");
95 event_base_loopbreak(base);
98 bufferevent_setcb(bev, NULL, conn_writecb, conn_eventcb, NULL);
99 bufferevent_enable(bev, EV_WRITE);
100 bufferevent_disable(bev, EV_READ);
102 bufferevent_write(bev, MESSAGE, strlen(MESSAGE));
106 conn_writecb(struct bufferevent *bev, void *user_data)
108 struct evbuffer *output = bufferevent_get_output(bev);
109 if (evbuffer_get_length(output) == 0) {
110 printf("flushed answer\n");
111 bufferevent_free(bev);
116 conn_eventcb(struct bufferevent *bev, short events, void *user_data)
118 if (events & BEV_EVENT_EOF) {
119 printf("Connection closed.\n");
120 } else if (events & BEV_EVENT_ERROR) {
121 printf("Got an error on the connection: %s\n",
122 strerror(errno));/*XXX win32*/
124 /* None of the other events can happen here, since we haven't enabled
126 bufferevent_free(bev);
130 signal_cb(evutil_socket_t sig, short events, void *user_data)
132 struct event_base *base = user_data;
133 struct timeval delay = { 2, 0 };
135 printf("Caught an interrupt signal; exiting cleanly in two seconds.\n");
137 event_base_loopexit(base, &delay);