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HP-UX 11i Version 3: February 2007

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getpeername — get address of connected peer


#include <sys/socket.h>


#include <x25/x25addrstr.h>

int getpeername(int s, void *addr, int *addrlen);

UNIX 03 Only (X/Open Sockets)

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

Obsolescent UNIX 95 Only (X/Open Sockets)

int getpeername(int s, struct sockaddr *addr, size_t *addrlen);


getpeername() returns the address of the peer socket connected to the socket indicated by s, where s is a socket descriptor. addr points to a socket address structure in which this address is returned. addrlen points to a variable that should be initialized to indicate the size of the address structure. On return, the variable contains the actual size of the address returned (in bytes). If addr does not point to enough space to contain the whole address of the peer, only the first addrlen bytes of the address are returned.


The addr struct contains the X.25 addressing information of the remote peer socket connected to socket s. However, the x25ifname[] field of the addr struct contains the name of the local X.25 interface through which the call arrived.

X/Open Sockets Compilation Environment

See xopen_networking(7).


Upon successful completion, getpeername() returns 0; otherwise it returns -1 and sets errno to indicate the error.


getpeername() fails if any of the following conditions are encountered:


s is not a valid file descriptor.


s is a valid file descriptor, but it is not a socket.


The socket is not connected.


No buffer space is available to perform the operation.


addr or addrlen are not valid pointers.


The socket has been shut down.


The operation was interrupted by a signal. Application needs to retry the operation to get the address of peer socket.

Not all possible errno values are documented in this manpage due to dependencies from the underlying protocol modules.


Currently, the socklen_t and size_t types are the same size. This is compatible with the UNIX 95 and UNIX 03 profiles. However, in a future release, socklen_t might be a different size. In that case, passing a size_t pointer will evoke compile-time warnings, which must be corrected in order for the application to behave correctly. Applications that use socklen_t now, where appropriate, will avoid such migration problems. On the other hand, applications that need to be portable to the UNIX 95 profile should follow the X/Open specification (see xopen_networking(7)).


Linking binary objects compiled to X/Open Sockets specification and binary objects compiled to HP-UX BSD Sockets specification to the same executable may result in unexpected behavior, including application abnormal termination and unexpected socket errors. See xopen_networking(7) for details and remedy.


Currently, the default behavior is the HP-UX BSD Sockets; however, it might be changed to X/Open Sockets in a future release. At that time, any HP-UX BSD Sockets behavior that is incompatible with X/Open Sockets might be obsoleted. Applications that conform to the X/Open specification now will avoid migration problems (see xopen_networking(7)).


getpeername() was developed by HP and the University of California, Berkeley.


getpeername(): XPG4, UNIX 95, UNIX 03

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