GETPEERNAME(3P) POSIX Programmer's Manual GETPEERNAME(3P)PROLOG
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.
NAMEgetpeername — get the name of the peer socket
int getpeername(int socket, struct sockaddr *restrict address,
socklen_t *restrict address_len);
The getpeername() function shall retrieve the peer address of the spec‐
ified socket, store this address in the sockaddr structure pointed to
by the address argument, and store the length of this address in the
object pointed to by the address_len argument.
The address_len argument points to a socklen_t object which on input
specifies the length of the supplied sockaddr 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 supplied sockaddr struc‐
ture, 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 address is
Upon successful completion, 0 shall be returned. Otherwise, −1 shall be
returned and errno set to indicate the error.
The getpeername() function shall fail if:
EBADF The socket argument is not a valid file descriptor.
EINVAL The socket has been shut down.
The socket is not connected or otherwise has not had the peer
The socket argument does not refer to a socket.
The operation is not supported for the socket protocol.
The getpeername() function may fail if:
Insufficient resources were available in the system to complete
The following sections are informative.
SEE ALSOaccept(), bind(), getsockname(), socket()
The Base Definitions volume of POSIX.1‐2008, <sys_socket.h>
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
cal and Electronics Engineers, Inc and The Open Group. (This is
POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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 http://www.unix.org/online.html .
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IEEE/The Open Group 2013 GETPEERNAME(3P)