Simple example of QueryPerformanceCounter Usage

QueryPerformanceCounterExample.cpp

// If needed #include Winbase.h - link: Kernel32.lib

double PCFreq = 0.0;
LONGLONG CounterStart = 0;

void StartCounter()
{
	LARGE_INTEGER li;
	if (!QueryPerformanceFrequency(&li))
		cout << "QueryPerformanceFrequency failed!\n";

	PCFreq = double(li.QuadPart) / 1000.0;

	QueryPerformanceCounter(&li);
	CounterStart = li.QuadPart;
}

double GetCounter()
{
	LARGE_INTEGER li;
	QueryPerformanceCounter(&li);
	return double(li.QuadPart - CounterStart) / PCFreq;
}

void TestTimer()
{
	StartCounter(); // <--- only needs called once per run
	
	cout << "Starting Timed Test" << endl;
	double start = GetCounter();
	
	// Test long/slow artifact here: should take at least > 10us, or call many times in a loop until it does
	
	double end = GetCounter();
	double elapsed = end - start;
	printf("  ::: Elapsed availableKeywords(): %3.3f ms, %3.3f sec, %3.3f min\n", elapsed,
		elapsed / 1000.0, elapsed / 1000.0 / 60.0);
}