close(2) closes a pipe or FIFO and dismantles its associated Streams. On the last close of one end of a pipe, an M_HANGUP message is sent to the other end of the pipe. Subsequent read(2) or getmsg(2) calls on that Stream head return the number of bytes read and zero when there are no more data. Subsequent write(2) or putmsg(2) requests fail with errno set to EPIPE. If the other end of the pipe is mounted, the last close of the pipe forces it to be unmounted.