NAME
        SelectInput -- Select a filehandle as the default input channel (V36)

   SYNOPSIS
        old_fh = SelectInput(fh)
        D0                   D1

        bptr selectinput(bptr)

   FUNCTION
        Set the current input as the default input for the process.
        This changes the value returned by input().  old_fh should
        be closed or saved as needed.

   INPUTS
        fh     - Newly default input handle

   RESULT
        old_fh - Previous default input filehandle

   SEE ALSO
        input(), selectoutput(), output()