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.
Library:
libc
Use the -l c option to qcc to link against this library. This library is usually included automatically.
Description:
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:
| Safety: | |
|---|---|
| Cancellation point | Yes |
| Interrupt handler | No |
| Signal handler | Yes |
| Thread | Yes |