shutdown - shut down part of a full-duplex connection
int shutdown(int s, int how));
The shutdown call causes all or part of a full-duplex con-
nection on the socket associated with s to be shut down. If
how is 0, further receives will be disallowed. If how is 1,
further sends will be disallowed. If how is 2, further
sends and receives will be disallowed.
On success, zero is returned. On error, -1 is returned, and
errno is set appropriately.
EBADF s is not a valid descriptor.
s is a file, not a socket.
The specified socket is not connected.
4.4BSD (the shutdown function call first appeared in