NAME
        Forbid -- forbid task rescheduling.

    SYNOPSIS
        Forbid()

        void Forbid(void);

    FUNCTION
        Prevents other tasks from being scheduled to run by the dispatcher,
        until a matching permit() is executed, or this task is scheduled to
        wait().  interrupts are not disabled.

        DO NOT USE THIS CALL WITHOUT GOOD JUSTIFICATION.  THIS CALL IS
        DANGEROUS!

    RESULTS
        The current task will not be rescheduled as long as it is ready to
        run.  In the event that the current task enters a wait state, other
        tasks may be scheduled.  Upon return from the wait state, the original
        task will continue to run without disturbing the Forbid().

        Calls to Forbid() nest. In order to restore normal task rescheduling,
        the programmer must execute exactly one call to permit() for every
        call to Forbid().

    WARNING
        In the event of a task entering a wait() after a forbid(), the system
        "breaks" the forbidden state and runs normally until the task which
        called Forbid() is rescheduled.  If caution is not taken, this can
        cause subtle bugs, since any device or DOS call will (in effect)
        cause your task to wait.

        Forbid() is not useful or safe from within interrupt code
        (All interrupts are always higher priority than tasks, and
        interrupts are allowed to break a Forbid()).

    NOTE
        This call is guaranteed to preserve all registers.

    SEE ALSO
        permit(), disable(), obtainsemaphore(), obtainsemaphoreshared()