1 .\" $OpenBSD: getpeername.2,v 1.16 2001/06/26 19:56:52 dugsong Exp $
2 .\" $NetBSD: getpeername.2,v 1.6 1995/10/12 15:40:56 jtc Exp $
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35 .\" @(#)getpeername.2 8.1 (Berkeley) 6/4/93
42 .Nd get name of connected peer
44 .Fd #include <sys/types.h>
45 .Fd #include <sys/socket.h>
47 .Fn getpeername "int s" "struct sockaddr *name" "socklen_t *namelen"
50 returns the address information of the peer connected to socket
52 One common use occurs when a process inherits an open socket, such as
53 TCP servers forked from
57 is used to determine the connecting client's IP address.
60 takes three parameters:
63 Contains the file descriptor of the socket whose peer should be looked up.
68 structure that will hold the address information for the connected peer.
69 Normal use requires one to use a structure
70 specific to the protocol family in use, such as
74 (IPv6), cast to a (struct sockaddr *).
76 For greater portability, especially with the newer protocol families, the new
77 .Li struct sockaddr_storage
80 is large enough to hold any of the other sockaddr_* variants.
81 On return, it can be cast to the correct sockaddr type,
82 based the protocol family contained in its ss_family field.
85 Indicates the amount of space pointed to by
89 If address information for the local end of the socket is required, the
91 function should be used instead.
95 does not point to enough space to hold the entire socket address, the
96 result will be truncated to
100 If the call succeeds, a 0 is returned and
102 is set to the actual size of the socket address returned in
106 is set and a value of \-1 is returned.
110 is set to one of the following:
115 is not a valid descriptor.
119 is a file, not a socket.
121 The socket is not connected.
123 Insufficient resources were available in the system
124 to perform the operation.
128 parameter points to memory not in a valid part of the
129 process address space.
140 function call appeared in