DWORD WINAPI WriterThread(PVOID pvParam) {
int nThreadNum = PtrToUlong(pvParam);
HWND hWndLB = GetDlgItem(g_hWnd, IDC_CLIENTS);
for (int nRequestNum = 1; !g_fShutdown; nRequestNum++) {
CQueue::ELEMENT e = { nThreadNum, nRequestNum };
// Require access for writing
AcquireSRWLockExclusive(&g_srwLock);
// If the queue is full, fall asleep as long as the condition variable
// is not signaled
// Note: During the wait for acquiring the lock,
// a stop might have been received
if (g_q.IsFull() & !g_fShutdown) {
// No more room in the queue
AddText(hWndLB, TEXT("[%d] Queue is full: impossible to add %d"),
nThreadNum, nRequestNum);
// --> Need to wait for a reader to empty a slot before acquiring
// the lock again
SleepConditionVariableSRW(&g_cvReadyToProduce, &g_srwLock,
INFINITE, 0);
}
// Other writer threads might still be blocked on the lock
// --> Release the lock and notify the remaining writer threads to quit
if (g_fShutdown) {
// Show that the current thread is exiting
AddText(hWndLB, TEXT("[%d] bye bye"), nThreadNum);
// No need to keep the lock any longer
ReleaseSRWLockExclusive(&g_srwLock);
// Signal other blocked writers threads that it is time to exit
WakeAllConditionVariable(&g_cvReadyToProduce);
// Bye bye
return(0);
} else {
// Add the new ELEMENT into the queue
g_q.AddElement(e);
// Show result of processing element
AddText(hWndLB, TEXT("[%d] Adding %d"), nThreadNum, nRequestNum);
// No need to keep the lock any longer
ReleaseSRWLockExclusive(&g_srwLock);
// Signal reader threads that there is an element to consume
WakeAllConditionVariable(&g_cvReadyToConsume);
// Wait before adding a new element
Sleep(1500);
}
}
// Show that the current thread is exiting
AddText(hWndLB, TEXT("[%d] bye bye"), nThreadNum);
return(0);
}
