InterruptWait(), InterruptWait_r()

Wait for a hardware interrupt

Synopsis:

#include <sys/neutrino.h>

int InterruptWait( int flags,
                   const uint64_t * timeout );

int InterruptWait_r( int flags,
                     const uint64_t * timeout );

Arguments:

flags: This should currently be 0.
timeout: This should currently be NULL. This may change in future versions.

Use TimerTimeout() to achieve a timeout.

Library:

libc

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

These kernel calls wait for a hardware interrupt. The calling thread should have attached a handler to the interrupt, by calling InterruptAttach() or InterruptAttachEvent(). The call to InterruptWait() or InterruptWait_r() blocks waiting for an interrupt handler to return an event with notification type SIGEV_INTR (i.e. a hardware interrupt).

The InterruptWait() and InterruptWait_r() functions are identical except in the way they indicate errors. See the Returns section for details.

If the notification event occurs before InterruptWait() is called, a pending flag is set. When InterruptWait() is called, the flag is checked; if set, it's cleared and the call immediately returns with success.

On a multicore system, a thread that calls InterruptWait() runs on any CPU, limited only by the scheduler and the runmask.

Blocking states

STATE_INTR: The thread is waiting for an interrupt handler to return a SIGEV_INTR event.

Returns:

The only difference between these functions is the way they indicate errors:

InterruptWait(): If an error occurs, -1 is returned and errno is set. Any other value returned indicates success.
InterruptWait_r(): EOK is returned on success. This function does NOT set errno. If an error occurs, any value in the Errors section may be returned.

Errors:

EINTR: The call was interrupted by a signal.
ENOTSUP: The reserved arguments aren't NULL.
ETIMEDOUT: A kernel timeout unblocked the call. See TimerTimeout().

Classification:

QNX Neutrino

Safety:
Cancellation point	Yes
Interrupt handler	No
Signal handler	Yes
Thread	Yes