shutdown - shut down part of a full-duplex connection
int s, how;
The shutdown call causes all or part of a full-duplex connection on the socket associated with s to be shut down. If how is 0, then fur-
ther receives will be disallowed. If how is 1, then further sends will be disallowed. If how is 2, then further sends and receives will
A 0 is returned if the call succeeds, -1 if it fails.
The call succeeds unless:
[EBADF] S is not a valid descriptor.
[ENOTSOCK] S is a file, not a socket.
[ENOTCONN] The specified socket is not connected.