NAME
connect - initiate a connection on a socket
SYNOPSIS
#include <sys/types.h> /* See NOTES */ #include <sys/socket.h> int connect(int sockfd, const struct sockaddr *addr, socklen_t addrlen);
DESCRIPTION).
RETURN VALUE
If the connection or binding succeeds, zero is returned. On error, -1 is returned, and errno is set appropriately.
ERRORS
The following are general socket errors only. There may be other domain-specific error codes. EACCES For Unix domain sockets, which are identified by pathname: Write permission is denied on the socket file, or search permission is denied for one of the directories in the path prefix. (See also path_resolution(7).) EACCES, EPERM The user tried to connect to a broadcast address without having the socket broadcast flag enabled or the connection request failed because of a local firewall rule. EADDRINUSE Local address is already in use. EAFNOSUPPORT The passed address didn’t have the correct address family in its sa_family field. EAGAIN No more free local ports or insufficient entries in the routing cache. For AF_INET see the description of /proc/sys/net/ipv4/ip_local_port_range ip(7) for information on how to increase the number of local ports. EALREADY The socket is non-blocking and a previous connection attempt has not yet been completed. EBADF The file descriptor is not a valid index in the descriptor table. ECONNREFUSED No-one listening on the remote address. EFAULT The socket structure address is outside the user’s address space. EINPROGRESS The socket is non-blocking). EINTR The system call was interrupted by a signal that was caught; see signal(7). EISCONN The socket is already connected. ENETUNREACH Network is unreachable. ENOTSOCK The file descriptor is not associated with a socket. ETIMEDOUT Timeout while attempting connection. The server may be too busy to accept new connections. Note that for IP sockets the timeout may be very long when syncookies are enabled on the server.
CONFORMING TO
SVr4, 4.4BSD, (the connect() function first appeared in 4.2BSD), POSIX.1-2001.
NOTES
POSIX.1-2001).
EXAMPLE
An example of the use of connect() is shown in getaddrinfo(3).
SEE ALSO
accept(2), bind(2), getsockname(2), listen(2), socket(2), path_resolution(7)
COLOPHON
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