I didn't find how to call the queryperformancecounter function. I tried this. Returns errors, doesn't know what BOOL and LARGE_INTEGER are. import core.sys.windows.windows; import core.sys.windows.w32api; import core.sys.windows.winbase; pragma(lib, "kernel32"); extern (Windows) { BOOL QueryPerformanceCounter(LARGE_INTEGER *lpPerformanceCount); } void main() {}