NAME

       getpeername - get name of connected peer socket

SYNOPSIS

       #include <sys/socket.h>

       int getpeername(int sockfd, struct sockaddr *addr, socklen_t *addrlen);

DESCRIPTION

       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.

RETURN VALUE

       On success, zero is returned.  On error, -1 is returned, and errno is set appropriately.

ERRORS

       EBADF  The argument sockfd is not a valid descriptor.

       EFAULT The addr argument points to memory not in a valid part of the process address space.

       EINVAL addrlen is invalid (e.g., is negative).

       ENOBUFS
              Insufficient resources were available in the system to perform the operation.

       ENOTCONN
              The socket is not connected.

       ENOTSOCK
              The file descriptor sockfd does not refer to a socket.

CONFORMING TO

       POSIX.1-2001, POSIX.1-2008, SVr4, 4.4BSD (getpeername() first appeared in 4.2BSD).

NOTES

       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).

SEE ALSO

       accept(2), bind(2), getsockname(2), ip(7), socket(7), unix(7)

COLOPHON

       This page is part of release 4.04 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
       http://www.kernel.org/doc/man-pages/.

Linux                                              2015-12-28                                     GETPEERNAME(2)