int getpeername(int sockfd, struct sockaddr *addr, socklen_t *addrlen);
returns the address of the peer connected to the socket
in the buffer pointed to by
argument should be initialized to indicate the amount of space pointed to
On return it contains the actual size of the name returned (in bytes).
The name is truncated if the buffer provided is too small.
The returned address is truncated if the buffer provided is too small;
in this case,
will return a value greater than was supplied to the call.
On success, zero is returned.
On error, -1 is returned, and
is set appropriately.
is not a valid descriptor.
argument points to memory not in a valid part of the
process address space.
is invalid (e.g., is negative).
Insufficient resources were available in the system
to perform the operation.
The socket is not connected.
is a file, not a socket.
SVr4, 4.4BSD (the
function call first appeared in 4.2BSD), POSIX.1-2001.
The third argument of
is in reality an
(and this is what 4.x BSD and libc4 and libc5 have).
Some POSIX confusion resulted in the present
also used by glibc.