int
getsockname(
int s
, struct sockaddr * restrict name
, socklen_t * restrict namelen
)
)
returns the locally bound address information for a specified socket.
Common uses of this function are as follows:
)
is used to retrieve the kernel-assigned port number.
)
is used to retrieve the local IP address for the connection.
)
can be used.
getsockname()
takes three parameters:
s
,
Contains the file descriptor for the socket to be looked up.
name
points to a
sockaddr
structure which will hold the resulting address information.
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 (such as newer protocol families) the new
structure sockaddr_storage exists.
sockaddr_storage
is large enough to hold any of the other sockaddr_* variants.
On return, it should be cast to the correct sockaddr type,
according to the current protocol family.
namelen
indicates the amount of space pointed to by
name
,
in bytes.
Upon return,
namelen
is set to the actual size of the returned address information.
If the address of the destination socket for a given socket connection is needed, the getpeername(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.
)
returns a 0, 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.
EBADF
]
s
is not a valid descriptor.
ENOTSOCK
]
s
is a file, not a socket.
EINVAL
]
ENOBUFS
]
EFAULT
]
name
parameter points to memory not in a valid part of the process address space.
)
function call appeared in
4.2BSD.
)
returns a zero length name.