The Single UNIX ® Specification, Version 2
Copyright © 1997 The Open Group


getpeername - get the name of the peer socket


#include <sys/socket.h>

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


The getpeername() function retrieves the peer address of the specified socket, stores this address in the sockaddr structure pointed to by the address argument, and stores the length of this address in the object pointed to by the address_len argument.

If the actual length of the address is greater than the length of the supplied sockaddr structure, the stored address will be truncated.

If the protocol permits connections by unbound clients, and the peer is not bound, then the value stored in the object pointed to by address is unspecified.


Upon successful completion, 0 is returned. Otherwise, -1 is returned and errno is set to indicate the error.


The getpeername() function will fail if:
The socket argument is not a valid file descriptor.
The address or address_len parameter can not be accessed or written.
The socket has been shut down.
The socket is not connected or otherwise has not had the peer prespecified.
The socket argument does not refer to a socket.
The operation is not supported for the socket protocol.

The getpeername() function may fail if:

Insufficient resources were available in the system to complete the call.
There were insufficient STREAMS resources available for the operation to complete.


accept(), bind(), getsockname(), socket(), <sys/socket.h>.

UNIX ® is a registered Trademark of The Open Group.
Copyright © 1997 The Open Group
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