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