NAME

SYNOPSIS

cc [ flag ... ] file ... -lsocket  -lnsl  [ library ... ]
#include <sys/types.h>
#include <sys/socket.h>
int connect(int s, const struct sockaddr *name, int namelen);

DESCRIPTION

EXAMPLES

The following sample C program shows how to create and connect to a remote host using TCP. The program should be compiled and linked against libnsl and libsocket. For example, if the contents of this example where in a file called example.c, one would run cc example.c -lnsl -lsocket.

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <inttypes.h>
#include <stdio.h>
#include <strings.h>
#include <stdlib.h>
#include <errno.h>
#include <port.h>
#include <unistd.h>
#include <assert.h>
int
main(int argc, char *argv[])
{
	char *eptr;
	long port;
	int sock, ret, eport;
	struct sockaddr_in6 sin6;
	if (argc != 3) {
		fprintf(stderr, "connect: <IP> <port>\n");
		return (1);
	}
	bzero(&sin6, sizeof (struct sockaddr_in6));
	sin6.sin6_family = AF_INET6;
	/*
	 * Try to parse as an IPv6 address and then try v4.
	 */
	ret = inet_pton(AF_INET6, argv[1], &sin6.sin6_addr);
	if (ret == -1) {
		perror("inet_pton");
		return (1);
	} else if (ret == 0) {
		struct in_addr v4;
		ret = inet_pton(AF_INET, argv[1], &v4);
		if (ret == -1) {
			perror("inet_pton");
			return (1);
		} else if (ret == 0) {
			fprintf(stderr, "connect: %s is not a valid "
			    "IPv4 or IPv6 address\n", argv[1]);
			return (1);
		}
		/* N.B. Not a portable macro */
		IN6_INADDR_TO_V4MAPPED(&v4, &sin6.sin6_addr);
	}
	errno = 0;
	port = strtol(argv[2], &eptr, 10);
	if (errno != 0 || *eptr != '\0') {
		fprintf(stderr, "failed to parse port %s\n", argv[2]);
		return (1);
	}
	if (port <= 0 || port > UINT16_MAX) {
		fprintf(stderr, "invalid port: %ld\n", port);
		return (1);
	}
	sin6.sin6_port = htons(port);
	sock = socket(AF_INET6, SOCK_STREAM | SOCK_NONBLOCK, 0);
	if (sock < 0) {
		perror("socket");
		return (1);
	}
	eport = port_create();
	if (eport < 0) {
		perror("port_create");
		(void) close(sock);
		return (1);
	}
	ret = connect(sock, (struct sockaddr *)&sin6,
	    sizeof (struct sockaddr_in6));
	if (ret != 0 && errno != EINPROGRESS && errno != EINTR) {
		perror("connect");
		(void) close(sock);
		(void) close(eport);
		return (1);
	}
	if (ret != 0) {
		port_event_t pe;
		int err;
		socklen_t sz = sizeof (err);
		if (port_associate(eport, PORT_SOURCE_FD, sock, POLLOUT,
		    NULL) != 0) {
			perror("port_associate");
			(void) close(sock);
			(void) close(eport);
			return (1);
		}
		if (port_get(eport, &pe, NULL) != 0) {
			perror("port_get");
			(void) close(sock);
			(void) close(eport);
			return (1);
		}
		assert(pe.portev_source == PORT_SOURCE_FD);
		assert(pe.portev_object == (uintptr_t)sock);
		if (getsockopt(sock, SOL_SOCKET, SO_ERROR, &err, &sz) != 0) {
			perror("getsockopt");
			(void) close(sock);
			(void) close(eport);
			return (1);
		}
		if (err != 0) {
			/* Asynch connect failed */
			fprintf(stderr, "asynchronous connect: %s\n",
			    strerror(err));
			(void) close(sock);
			(void) close(eport);
			return (1);
		}
	}
	/* Read and write to the socket and then clean up */
	return (0);
}

RETURN VALUES

ERRORS

EACCES

EADDRINUSE

EADDRNOTAVAIL

EAFNOSUPPORT

EALREADY

EBADF

ECONNREFUSED

EINPROGRESS

EINTR

EINVAL

EIO

EISCONN

ELOOP

ENETUNREACH

EHOSTUNREACH

ENOENT

ENOENT

ENOSR

ENXIO

ETIMEDOUT

EWOULDBLOCK

The following errors are specific to connecting names in the UNIX domain. These errors might not apply in future versions of the UNIX IPC domain.

ENOTDIR

ENOTSOCK

ENOTSOCK

EPROTOTYPE

ATTRIBUTES

SEE ALSO