osx man page for getsockname

GETSOCKNAME(2)						      BSD System Calls Manual						    GETSOCKNAME(2)

NAME
     getsockname -- get socket name

SYNOPSIS
     #include <sys/socket.h>

     int
     getsockname(int socket, struct sockaddr *restrict address, socklen_t *restrict address_len);

DESCRIPTION
     The getsockname() fynction returns the current address for the specified socket.

     The address_len parameter should be initialized to indicate the amount of space pointed to by address.  On return it contains the actual size
     of the address returned (in bytes).

     The address is truncated if the buffer provided is too small.

RETURN VALUES
     The getsockname() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to
     indicate the error.

ERRORS
     The getsockname() system call will succeed unless:

     [EBADF]		The argument socket is not a valid file descriptor.

     [EFAULT]		The address parameter points to memory not in a valid part of the process address space.

     [EINVAL]		socket has been shut down.

     [ENOBUFS]		Insufficient resources were available in the system to perform the operation.

     [ENOTSOCK] 	The argument socket is not a socket (e.g., a plain file).

     [EOPNOTSUPP]	getsockname() is not supported for the protocol in use by socket.

SEE ALSO
     bind(2), socket(2)

BUGS
     Names bound to sockets in the UNIX domain are inaccessible; getsockname() returns a zero-length address.

HISTORY
     The getsockname() call appeared in 4.2BSD.

4.2 Berkeley Distribution					   June 4, 1993 					 4.2 Berkeley Distribution