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getpeername(2) [netbsd man page]

GETPEERNAME(2)						      BSD System Calls Manual						    GETPEERNAME(2)

getpeername -- get name of connected peer LIBRARY
Standard C Library (libc, -lc) SYNOPSIS
#include <sys/socket.h> int getpeername(int s, struct sockaddr * restrict name, socklen_t * restrict namelen); DESCRIPTION
The getpeername() function returns the name of the peer connected to the socket s. One common use occurs when a process inherits an open socket, such as TCP servers forked from inetd(8). In this scenario, getpeername() is used to determine the connecting client's IP address. The function 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 sock- addr *). For greater portability, especially with the newer protocol families, the new struct sockaddr_storage should be used. sockaddr_storage is large enough to hold any of the other sockaddr_* variants. On return, it can be cast to the correct sock- addr type, based on the protocol family contained in its ss_family field. 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. RETURN VALUES
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. ERRORS
The call succeeds unless: [EBADF] The argument s is not a valid descriptor. [EFAULT] The name parameter points to memory not in a valid part of the process address space. [ENOBUFS] Insufficient resources were available in the system to perform the operation. [ENOTCONN] The socket is not connected. [ENOTSOCK] The argument s is a file, not a socket. SEE ALSO
accept(2), bind(2), getsockname(2), socket(2) STANDARDS
The function conforms to IEEE Std 1003.1-2008 (``POSIX.1''). HISTORY
The getpeername() function call appeared in 4.2BSD. BSD
June 3, 2011 BSD

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getpeername(3XNET)				   X/Open Networking Services Library Functions 				getpeername(3XNET)

getpeername - get the name of the peer socket SYNOPSIS
cc [ flag ... ] file ... -lxnet [ library ... ] #include <sys/socket.h> int getpeername(int socket, struct sockaddr *restrict address, socklen_t *restrict address_len); DESCRIPTION
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. RETURN VALUES
Upon successful completion, 0 is returned. Otherwise, -1 is returned and errno is set to indicate the error. ERRORS
The getpeername() function will fail if: EBADF The socket argument is not a valid file descriptor. EFAULT The address or address_len parameter can not be accessed or written. EINVAL The socket has been shut down. ENOTCONN The socket is not connected or otherwise has not had the peer prespecified. ENOTSOCK The socket argument does not refer to a socket. EOPNOTSUPP The operation is not supported for the socket protocol. The getpeername() function may fail if: ENOBUFS Insufficient resources were available in the system to complete the call. ENOSR There were insufficient STREAMS resources available for the operation to complete. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ |MT-Level |MT-Safe | +-----------------------------+-----------------------------+ SEE ALSO
accept(3XNET), bind(3XNET), getsockname(3XNET), socket(3XNET), attributes(5), standards(5) SunOS 5.11 10 Jun 2002 getpeername(3XNET)
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