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getpeername(2)
NAME
  getpeername - Gets the name of the peer socket

SYNOPSIS
  #include <sys/socket.h>

  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
  compatibility (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(): XNS4.0, XNS5.0

  Refer to the standards(5) reference page for more information about
  industry 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 specifying 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
  getpeername() 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
  _Egetpeername 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()
  function 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
  following 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 operation 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.

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

  Standards: standards(5).

  Network Programmer's Guide

Index for Section 2

Alphabetical listing for G

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