#include <sys/types.h>
#include <sys/socket.h>
#include <sys/poll.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <fcntl.h>
#include <sys/errno.h>

int main(int argc, char *argv[])
{
	int ret;
	int s;
	unsigned short port;
	struct sockaddr_in sin;
	struct hostent *he;
	int val = 64 * 1024;
	int time_limit = 30 * 1000;
	int farg;
	struct pollfd polldata;
	int pollret;
	int so_error;
	socklen_t so_error_size;

	if (argc < 3)
		printf ("usage: %s <name|ip-addr> <TCP-port>\n", argv[0]);

	memset ((char *)&sin, 0, sizeof (sin));
	he = gethostbyname (argv[1]);
	if (he == NULL)
		return(errno);

	port = htons (atoi (argv[2]));

	s = socket (AF_INET, SOCK_STREAM, 0);
	if (s == -1)
		return(errno);

	setsockopt (s, SOL_SOCKET, SO_RCVBUF, (char *) &val, sizeof (val));
	setsockopt (s, SOL_SOCKET, SO_SNDBUF, (char *) &val, sizeof (val));

	val = 1;
	setsockopt (s, IPPROTO_TCP, TCP_NODELAY, (char *) &val, sizeof (val));

	farg = fcntl (s, F_GETFL);
	farg |= O_NONBLOCK;
	fcntl (s, F_SETFL, farg);

	farg = fcntl (s, F_GETFL);
	if (farg & O_NONBLOCK)
		printf ("I/O is asynchronous\n");
	else
		printf ("I/O is synchronous\n");

	sin.sin_port = (unsigned int) port;
	sin.sin_family = AF_INET;
	strncpy((char *)&sin.sin_addr, he->h_addr, he->h_length);

	ret = connect (s, (struct sockaddr *)&sin, sizeof (sin));
	if (ret == -1)
	{
		printf ("connect() failed. errno = %d (%s)\n", errno, strerror (errno));
		if (errno != EINPROGRESS)
			return(errno);
	}

	polldata.fd = s;
	polldata.events = POLLOUT|POLLERR;
	polldata.revents = 0;

	pollret = poll (&polldata, 1, time_limit);
	printf ("pollret = %d\n", pollret);

	switch (pollret)
	{
		case 1:
			so_error = EBADF;
			so_error_size = sizeof (so_error);

			getsockopt (s, SOL_SOCKET, SO_ERROR, &so_error, &so_error_size);

			if ((polldata.revents & POLLOUT) == POLLOUT && so_error == 0)
				printf ("No error on socket\n");
			else
				printf ("Error on socket: so_error = %d (%s)\n", so_error, strerror (so_error));
			ret = so_error;
			break;

		case 0:
			printf ("poll() timed out\n");
			ret = errno;
			break;

		case -1:
			printf ("poll() failed. errno = %d (%s)\n", errno, strerror (errno));
			ret = errno;
			break;
	}

	close (s);

	return(ret); 
}