#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <netdb.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <fcntl.h>

int connect_nonblocking(int sockfd, const struct sockaddr * saptr, socklen_t salen, int nsec)
{
	int flags, n, error;
	socklen_t len;
	fd_set rset, wset;
	struct timeval tval;
		
	flags = Fcntl(sockfd, F_GETFL, 0);
	Fcntl(sockfd, F_SETFL, flags | O_NONBLOCK);
	
	error = 0;
	if((n = connect(sockfd, (struct sockaddr *) saptr, salen)) < 0)
		if(errno != EINPROGRESS)
			return(-1);
		
	if(n == 0)
		goto done;
	
	FD_ZERO(&rset);
	FD_SET(sockfd, &rset);
	wset = rset;
	tval.tv_sec = nsec;
	tval.tv_usec = 0;
	
	if((n = Select(sockfd + 1, &rset, &wset, NULL, nsec ? &tval : NULL)) == 0)
	{
		close(sockfd);
		errno = ETIMEDOUT;
		return(-1);
	}
	if(FD_ISSET(sockfd, &rset) || FD_ISSET(sockfd, &wset))
	{
		len = sizeof(error);
		if(getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &error, &len) < 0)
			return(-1);
	}
	else
		err_quit("select error: sockfd not set");
	
	done:
	Fcntl(sockfd, F_SETFL, flags);
	
	if(error)
	{
		close(sockfd);
		errno= error;
		return(-1);
	}
	return(0);
}