CONNECT(2) — SYSTEM CALLS

NAME

connect − initiate a connection on a socket

SYNOPSIS

#include <sys/types.h>
#include <sys/socket.h>

connect(s, name, namelen)
int s;
struct sockaddr ∗name;
int namelen;

DESCRIPTION

The parameter s is a socket. If it is of type SOCK_DGRAM, then this call permanently specifies the peer to which datagrams are to be sent; if it is of type SOCK_STREAM, then this call attempts to make a connection to another socket. The other socket is specified by name which is an address in the communications space of the socket. Each communications space interprets the name parameter in its own way.

RETURN VALUE

If the connection or binding succeeds, then 0 is returned. Otherwise a −1 is returned, and a more specific error code is stored in errno.

ERRORS

The call fails if:

EBADF s is not a valid descriptor.

ENOTSOCK s is a descriptor for a file, not a socket.

EADDRNOTAVAIL The specified address is not available on this machine.

EAFNOSUPPORT Addresses in the specified address family cannot be used with this socket.

EISCONN The socket is already connected.

ETIMEDOUT Connection establishment timed out without establishing a connection.

ECONNREFUSED The attempt to connect was forcefully rejected.

ENETUNREACH The network isn’t reachable from this host.

EADDRINUSE The address is already in use.

EFAULT The name parameter specifies an area outside the process address space.

EWOULDBLOCK The socket is non-blocking and the and the connection cannot be completed immediately. It is possible to select(2) the socket while it is connecting by selecting it for writing.

EINTR A read from a slow device was interrupted before any data arrived by the delivery of a signal.

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

ENOTDIR A component of the path prefix of the path name in name is not a directory.

EINVAL The path name in name contains a character with the high-order bit set.

ENAMETOOLONG
The length of a component of the path name in name exceeds 255 characters, or the length of the entire path name in name exceeds 1023 characters.

ENOENT A component of the path prefix of the path name in name does not exist.

ENOENT The socket referred to by the path name in name does not exist.

EACCES Search permission is denied for a component of the path prefix of the path name in name.

ELOOP Too many symbolic links were encountered in translating the path name in name.

EIO An I/O error occurred while reading from or writing to the file system.

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