Use the function
getsockname to examine the address of an
Internet socket. The prototype for this function is in the header file
Preliminary: | MT-Safe | AS-Safe | AC-Safe mem/hurd | See POSIX Safety Concepts.
getsocknamefunction returns information about the address of the socket socket in the locations specified by the addr and length-ptr arguments. Note that the length-ptr is a pointer; you should initialize it to be the allocation size of addr, and on return it contains the actual size of the address data.
The format of the address data depends on the socket namespace. The length of the information is usually fixed for a given namespace, so normally you can know exactly how much space is needed and can provide that much. The usual practice is to allocate a place for the value using the proper data type for the socket's namespace, then cast its address to
struct sockaddr *to pass it to
The return value is
0on success and
-1on error. The following
errnoerror conditions are defined for this function:
- The socket argument is not a valid file descriptor.
- The descriptor socket is not a socket.
- There are not enough internal buffers available for the operation.
You can't read the address of a socket in the file namespace. This is consistent with the rest of the system; in general, there's no way to find a file's name from a descriptor for that file.