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 file 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

       For background on the socklen_t type, see 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  5.10  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/.

Linux                                              2017-09-15                                     GETPEERNAME(2)