GETSOCKNAME(2) System Calls Manual GETSOCKNAME(2)

getsockname — get socket name

#include <sys/socket.h>

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

The () function 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.

Note: For the UNIX domain, the address length returned is the address_len parameter passed to the previous bind(2) system call and not the sa_len field of the address parameter passed to bind(2).

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.

The getsockname() system call will succeed unless:

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The argument socket is not a valid file descriptor.
[]
The address parameter points to memory not in a valid part of the process address space.
[]
socket has been shut down.
[]
Insufficient resources were available in the system to perform the operation.
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The argument socket is not a socket (e.g., a plain file).
[]
getsockname() is not supported for the protocol in use by socket.

bind(2), socket(2)

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

The getsockname() call appeared in 4.2BSD.

June 4, 1993 BSD 4.2