InterruptUnmask()

Arguments:

intr

The interrupt you want to unmask.

id

The value returned by InterruptAttach(), InterruptAttachArray(), or InterruptAttachEvent(), or -1 if you don't want the kernel to track interrupt maskings and unmaskings for each handler.

If you set the _NTO_INTR_FLAGS_TRK_MSK flag when calling the interrupt attach function, you must pass in a proper ID value (not -1). This ID value, along with the flag setting, allows better error recovery if a process unexpectedly terminates because it lets the kernel know how many times to call InterruptUnmask().

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The InterruptUnmask() kernel call enables the hardware interrupt specified by intr for the interrupt handler specified by id when the mask count reaches zero. You can call this function from a thread or from an interrupt handler.

If id isn't -1, the calling thread must be in the process that attached the interrupt. Otherwise the function fails with an error of EPERM.

If id is -1, then before you call this function from a thread:

• The process must have the PROCMGR_AID_IO ability enabled. For more information, see procmgr_ability().
• The calling thread must have obtained I/O privileges by calling:

  ThreadCtl( _NTO_TCTL_IO_LEVEL, (void*)_NTO_IO_LEVEL_1 );
  

If you're in an ISR, you must have had proper permissions, so the call will never fail for that reason.

Calls to InterruptMask() are counted; the interrupt isn't unmasked until InterruptUnmask() has been called once for every call to InterruptMask().

Returns:

The current mask count, or -1 if an error occurs (errno is set).

Errors:

EINVAL

Not a supported hardware interrupt intr.

ESRCH

The id parameter is neither something returned by InterruptAttach(), InterruptAttachArray(), or InterruptAttachEvent(), nor -1.

EPERM

One of the following errors occurred:

• The function was called from a process other than the one that called one of the InterruptAttach*() functions and obtained id.
• The caller passed an id of -1 but didn't request I/O privileges by first calling ThreadCtl( _NTO_TCTL_IO_LEVEL, (void*)_NTO_IO_LEVEL_1 ).

Classification:

QNX Neutrino