get name of connected peer
s, struct sockaddr
returns the address information of the peer connected to socket
s. One common use occurs when a process inherits an
open socket, such as TCP servers forked from
inetd(8). In this scenario,
used to determine the connecting client's IP address.
takes three parameters:
s contains the file descriptor of the socket whose peer should be looked up.
name points to a
sockaddr structure that will hold the address
information for the connected peer. Normal use requires one to use a
structure specific to the protocol family in use, such as
sockaddr_in (IPv4) or
sockaddr_in6 (IPv6), cast to a (struct sockaddr
For greater portability, especially with the newer protocol
families, the new
struct sockaddr_storage should be
sockaddr_storage is large enough to hold any
of the other sockaddr_* variants. On return, it can be cast to the correct
sockaddr type, based on the protocol family contained in its ss_family
namelen indicates the amount of space pointed to by name, in bytes.
If address information for the local end of the socket is required, the getsockname(2) function should be used instead.
If name does not point to enough space to hold the entire socket address, the result will be truncated to namelen bytes.
If the call succeeds, a 0 is returned and namelen is set to the actual size of the socket address returned in name. Otherwise, errno is set and a value of -1 is returned.
On failure, errno is set to one of the following:
- The argument s is not a valid descriptor.
- The argument s is a file, not a socket.
- The socket is not connected.
- Insufficient resources were available in the system to perform the operation.
- The name or namelen parameter points to memory not in a valid part of the process address space.
accept(2), bind(2), getsockname(2), socket(2), getpeereid(3)
getpeername() function conforms to
IEEE Std 1003.1-2008 (“POSIX.1”).
getpeername() function call appeared