Section: POSIX Programmer's Manual (3P)
This manual page is part of the POSIX Programmer's Manual.
The Linux implementation of this interface may differ (consult
the corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
--- get the name of the peer socket
int getpeername(int socket, struct sockaddr *restrict address,
socklen_t *restrict address_len);
function shall retrieve the peer address of the specified socket,
store this address in the
structure pointed to by the
argument, and store the length of this address in the object pointed
to by the
argument points to a
object which on input specifies the length of the supplied
structure, and on output specifies the length of the stored address.
If the actual length of the address is greater than the length of the
structure, the stored address shall be truncated.
If the protocol permits connections by unbound clients, and the peer is
not bound, then the value stored in the object pointed to by
Upon successful completion, 0 shall be returned. Otherwise, -1 shall
be returned and
set to indicate the error.
function shall fail if:
argument is not a valid file descriptor.
The socket has been shut down.
The socket is not connected or otherwise has not had the peer
argument does not refer to a socket.
The operation is not supported for the socket protocol.
function may fail if:
Insufficient resources were available in the system to complete the
The following sections are informative.
The Base Definitions volume of POSIX.1-2017,
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1-2017, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, 2018 Edition,
Copyright (C) 2018 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group.
In the event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online at
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