Docs » Autodocs » exec.library » Forbid
Forbid -- forbid task rescheduling.
Forbid()
void Forbid(void);
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!
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().
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()).
This call is guaranteed to preserve all registers.
Permit(), Disable(), ObtainSemaphore(), ObtainSemaphoreShared()
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