How to: Submitting callbacks
Example
The following example shows how to submit a callback to either the work port
or the completion port of a task queue. First, it submits a work callback. Then, at the end of the work callback, it submits a completion callback. This is typical usage. The SubmitCallbacks function is
used in subsequent scenarios for brevity.
void CALLBACK SampleCompletionCallback(void*, bool cancel)
{
printf("Completion invoked on thread %d. Cancel? %d.\r\n",
GetCurrentThreadId(), cancel);
}
void CALLBACK SampleWorkCallback(void* context, bool cancel)
{
printf("Worker invoked on thread %d. Cancel? %d.\r\n",
GetCurrentThreadId(), cancel);
XTaskQueueHandle queueFromContext = static_cast<XTaskQueueHandle>(context);
HRESULT hrCompletion = XTaskQueueSubmitCallback(
queueFromContext,
XTaskQueuePort::Completion,
nullptr,
SampleCompletionCallback);
if (FAILED(hrCompletion))
{
printf("Error 0x%x submitting completion.\r\n", hrCompletion);
}
}
void SubmitCallbacks(XTaskQueueHandle queue)
{
HRESULT hrWork = XTaskQueueSubmitCallback(
queue,
XTaskQueuePort::Work,
queue,
SampleWorkCallback);
if (FAILED(hrWork))
{
printf("Error 0x%x submitting work.\r\n", hrWork);
}
}