Disable hardware interrupts
Synopsis:
#include <sys/neutrino.h>
void InterruptDisable( void );
Library:
libc
Use the -l c option to
qcc
to link against this library.
This library is usually included automatically.
Description:
The InterruptDisable() function disables all hardware interrupts.
You can call it from a thread or from an interrupt handler.
Before calling this function:
If you don't do these things, the thread might SIGSEGV
when it calls InterruptDisable().
Reenable the interrupts by calling
InterruptEnable().
Use InterruptDisable() instead of an inline
cli to ensure hardware portability with non-x86 CPUs.
CAUTION:
- You should disable interrupts for as little time as possible (i.e., the minimum time you need to access
or deal with the hardware).
Failure to do so may result in increased interrupt latency and the inability to meet realtime deadlines.
- Some kernel calls and library routines reenable interrupts.
Masked interrupts aren't affected.
-
Use InterruptLock() and
InterruptUnlock() instead
of InterruptDisable()
and InterruptEnable().
The InterruptLock() and
InterruptUnlock() functions perform
the intended function on SMP hardware, and allow your interrupt thread
to run on any processor in the system.
- InterruptDisable() doesn't support nesting.
If a specific thread calls this function once and then calls it again without having
reenabled hardware interrupts, the second call has no effect,
and the first InterruptEnable() call after this point reenables hardware
interrupts.
Classification:
QNX Neutrino
| Safety: |
|
|---|
| Cancellation point |
No |
| Interrupt handler |
Yes |
| Signal handler |
Yes |
| Thread |
Yes |