import public System.Posix.Errno
import public System.Posix.Filepipe : Has Errno es => EIO1 f => CArrayIO 2 Fd -> f es ()Creates a pipe and writes the two file descriptors into the given C-array,
the read end at position 0 the write end at position 1.
mkfifo : Has Errno es => EIO1 f => String -> ModeT -> f es ()Creates a new FIFO (named pipe) on disc.