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getpeername(2)						       getpeername(2)



NAME
  getpeername -	Gets the name of the peer socket

SYNOPSIS

  #include <&lt;sys/socket.h>&gt;
  int getpeername (
	  int socket,
	  struct sockaddr *address,
	  socklen_t *address_len );

  [XNS4.0]  The	definition of the getpeername()	function in XNS4.0 uses	a
  size_t data type instead of a	socklen_t data type as specified in XNS5.0
  (the previous	definition).

  [Tru64 UNIX]	The following definition of the	getpeername() function does
  not conform to current standards and is supported only for backward compa-
  tibility (see	standards(5)):

  int getpeername (
	  int socket,
	  struct sockaddr *address,
	  int *address_len );


STANDARDS

  Interfaces documented	on this	reference page conform to industry standards
  as follows:

  getpeername():  XNS5.0

  Refer	to the standards(5) reference page for more information	about indus-
  try standards	and associated tags.

PARAMETERS

  socket    Specifies the descriptor number of a connected socket.

  address   Points to a	sockaddr structure, the	format of which	is determined
	    by the domain and by the behavior requested	for the	socket.	 The
	    sockaddr structure is an overlay for a sockaddr_in,	sockaddr_un,
	    sockaddr_in6, or sockaddr_storage structure, depending on which
	    of the supported address families is active.

	    [Tru64 UNIX]   If the compile-time option _SOCKADDR_LEN is
	    defined before the sys/socket.h header file	is included, the
	    sockaddr structure takes 4.4BSD behavior, with a field for speci-
	    fying the length of	the socket address.  Otherwise,	the default
	    4.3BSD sockaddr structure is used, with the	length of the socket
	    address assumed to be 14 bytes or less.

	    If _SOCKADDR_LEN is	defined, the 4.3BSD sockaddr structure is
	    defined with the name osockaddr.

  address_len
	    Specifies the length of the	sockaddr structure pointed to by the
	    address parameter.

DESCRIPTION

  The getpeername() function retrieves the name	of the peer socket connected
  to the specified socket.

  If the actual	length of the address is greater than the length of the
  sockaddr structure, the address is truncated.

  If the protocol permits connections by unbound clients and the peer is
  unbound, the value pointed to	by address is unspecified.

  A process created by another process can inherit open	sockets, but may need
  to identify the addresses of the sockets it has inherited.  The getpeer-
  name() function allows a process to retrieve the address of the peer socket
  at the remote	end of the socket connection.

NOTES

  The getpeername() function operates only on connected	sockets.

  A process can	use the	getsockname() function to retrieve the local address
  of a socket.

  [Tru64 UNIX]	When compiled in the X/Open UNIX environment or	the POSIX.1g
  socket environment, calls to the getpeername() function are internally
  renamed by prepending	_E to the function name.  When you are debugging a
  module that includes the getpeername() function and for which
  _XOPEN_SOURCE_EXTENDED or _POSIX_PII_SOCKET has been defined,	use _Eget-
  peername to refer to the getpeername() call.	See standards(5) for further
  information.

RETURN VALUES

  Upon successful completion, a	value of 0 (zero) is returned and the address
  parameter holds the address of the peer socket.  If the getpeername()	func-
  tion fails, a	value of -1 is returned	and errno is set to indicate the
  error.

ERRORS

  If the getpeername() function	fails, errno may be set	to one of the follow-
  ing values:

  [EBADF]   The	socket parameter is not	valid.

  [EFAULT]  The	address	or address_len parameter is not	in a readable OR
	    writable part of the user address space.

  [EINVAL]  The	socket has been	shut down.

  [ENOBUFS] Insufficient resources were	available in the system	to complete
	    the	call.

  [ENOSR]   The	available STREAMS resources were insufficient for the opera-
	    tion to complete.

  [ENOTCONN]
	    The	socket is not connected.

  [ENOTSOCK]
	    The	socket parameter refers	to a file, not a socket.

  [EOPNOTSUPP]
	    The	operation is not supported for the socket protocol.


RELATED	INFORMATION

  Functions: accept(2),	bind(2), getsockname(2), socket(2).

  Standards: standards(5).