kc3-lang/libevent/sample/hello-world.c

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• Hash : 2d3cd353
  Author :
  Date : 2016-03-04T19:18:18
  

  sample/hello-world: exAmple, not eXMple
  
  Fixes: #334
  

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• sample/hello-world.c

• /*
    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 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);
  }
  

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