NAME
        AttemptLockDosList -- Attempt to lock the Dos Lists for use (V36)

   SYNOPSIS
        dlist = AttemptLockDosList(flags)
        D0                          D1

        struct doslist *attemptlockdoslist(ulong)

   FUNCTION
        Locks the dos device list in preparation to walk the list.  If the
        list is 'busy' then this routine will return NULL.  See lockdoslist()
        for more information.

   INPUTS
        flags - Flags stating which types of nodes you want to lock.

   RESULT
        dlist - Pointer to the beginning of the list or NULL.  Not a valid
                node!

   BUGS
        In V36 through V39.23 dos, this would return NULL or 0x00000001 for
        failure.  Fixed in V39.24 dos (after kickstart 39.106).

   SEE ALSO
        lockdoslist(), unlockdoslist(), forbid(), nextdosentry()