getpeername — get name of connected peer socket
#include <sys/socket.h>
int
getpeername( |
int sockfd, |
| struct sockaddr *addr, | |
socklen_t *addrlen); |
getpeername() returns the
address of the peer connected to the socket sockfd, in the buffer pointed
to by addr. The
addrlen argument
should be initialized to indicate the amount of space pointed
to by addr. 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, addrlen will return a value
greater than was supplied to the call.
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 socket is not connected.
The file descriptor sockfd does not refer to
a socket.
The third argument of getpeername() 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).
For stream sockets, once a connect(2) has been
performed, either socket can call getpeername() to obtain the address of the
peer socket. On the other hand, datagram sockets are
connectionless. Calling connect(2) on a datagram
socket merely sets the peer address for outgoing datagrams
sent with write(2) or recv(2). The caller of
connect(2) can use
getpeername() to obtain the
peer address that it earlier set for the socket. However, the
peer socket is unaware of this information, and calling
getpeername() on the peer
socket will return no useful information (unless a connect(2) call was also
executed on the peer). Note also that the receiver of a
datagram can obtain the address of the sender when using
recvfrom(2).
This page is part of release 4.07 of the Linux man-pages project. A
description of the project, information about reporting bugs,
and the latest version of this page, can be found at
https://www.kernel.org/doc/man−pages/.
|
Copyright (c) 1983, 1991 The Regents of the University of California. All rights reserved. %%%LICENSE_START(BSD_4_CLAUSE_UCB) Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. 3. All advertising materials mentioning features or use of this software must display the following acknowledgement: This product includes software developed by the University of California, Berkeley and its contributors. 4. Neither the name of the University nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. %%%LICENSE_END (#)getpeername.2 6.5 (Berkeley) 3/10/91 Modified Sat Jul 24 16:37:50 1993 by Rik Faith <faithcs.unc.edu> Modified Thu Jul 30 14:37:50 1993 by Martin Schulze <joeydebian.org> Modified Sun Mar 28 21:26:46 1999 by Andries Brouwer <aebcwi.nl> Modified 17 Jul 2002, Michael Kerrisk <mtk.manpagesgmail.com> Added 'socket' to NAME, so that "man -k socket" will show this page. |