получить имя подключенного однорангового сокета (get name of connected peer socket)
Имя (Name)
getpeername - get name of connected peer socket
Синопсис (Synopsis)
#include <sys/socket.h>
int getpeername(int sockfd, struct sockaddr *restrict addr,
socklen_t *restrict addrlen);
Описание (Description)
getpeername() returns the address of the peer connected to the
socket sockfd, in the buffer pointed to by addr. The addrlen
argument should be initialized to indicate the amount of space
pointed to by addr. On return it contains the actual size of the
name returned (in bytes). The name is truncated if the buffer
provided is too small.
The returned address is truncated if the buffer provided is too
small; in this case, addrlen will return a value greater than was
supplied to the call.
Возвращаемое значение (Return value)
On success, zero is returned. On error, -1 is returned, and
errno is set to indicate the error.
Ошибки (Error)
EBADF The argument sockfd is not a valid file descriptor.
EFAULT The addr argument points to memory not in a valid part of
the process address space.
EINVAL addrlen is invalid (e.g., is negative).
ENOBUFS
Insufficient resources were available in the system to
perform the operation.
ENOTCONN
The socket is not connected.
ENOTSOCK
The file descriptor sockfd does not refer to a socket.
Стандарты (Conforming to)
POSIX.1-2001, POSIX.1-2008, SVr4, 4.4BSD (getpeername() first
appeared in 4.2BSD).
Примечание (Note)
For background on the socklen_t type, see accept(2).
For stream sockets, once a connect(2) has been performed, either
socket can call getpeername() to obtain the address of the peer
socket. On the other hand, datagram sockets are connectionless.
Calling connect(2) on a datagram socket merely sets the peer
address for outgoing datagrams sent with write(2) or recv(2).
The caller of connect(2) can use getpeername() to obtain the peer
address that it earlier set for the socket. However, the peer
socket is unaware of this information, and calling getpeername()
on the peer socket will return no useful information (unless a
connect(2) call was also executed on the peer). Note also that
the receiver of a datagram can obtain the address of the sender
when using recvfrom(2).
Смотри также (See also)
accept(2), bind(2), getsockname(2), ip(7), socket(7), unix(7)
