getsockname man page

getsockname — get socket name


#include <sys/socket.h>

int getsockname(int sockfd, struct sockaddr *addr, socklen_t *addrlen);


getsockname() returns the current address to which the socket sockfd is bound, in the buffer pointed to by addr. The addrlen argument should be initialized to indicate the amount of space (in bytes) pointed to by addr. On return it contains the actual size of the socket address.

The returned address is truncated if the buffer provided is too small; in this case, addrlen will return a value greater than was supplied to the call.

Return Value

On success, zero is returned. On error, -1 is returned, and errno is set appropriately.


The argument sockfd is not a valid file descriptor.
The addr argument points to memory not in a valid part of the process address space.
addrlen is invalid (e.g., is negative).
Insufficient resources were available in the system to perform the operation.
The file descriptor sockfd does not refer to a socket.

Conforming to

POSIX.1-2001, POSIX.1-2008, SVr4, 4.4BSD (getsockname() first appeared in 4.2BSD).


The third argument of getsockname() is in reality an int * (and this is what 4.x BSD and libc4 and libc5 have). Some POSIX confusion resulted in the present socklen_t, also used by glibc. See also accept(2).

See Also

bind(2), socket(2), getifaddrs(3), ip(7), socket(7), unix(7)

Referenced By

bind(2), bindresvport(3), connect(2), explain(1), explain(3), explain_getsockname(3), explain_getsockname_or_die(3), getifaddrs(3), getnameinfo(3), getpeereid(3), getpeername(2), if_nameindex(3), socket(2), socket(7), socketcall(2), syscalls(2), unix(7).

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