timer

Borland C++ Compiler 5.5

GetTickCountとtimeGetTimeによる時間測定
 第71回　割り込みイベント処理（timeBeginPeriodの周辺）

// GetTickCount / winbase.h / kernel32.lib
// timeGetTime / mmsystem.h / winmm.lib

#include <stdio.h>
#include <windows.h>

int main(int argc, char **argv)
{
	TIMECAPS	tc;
	DWORD	dwStart;
	DWORD	dwNext;
	DWORD	dwNow;
	int	i;

dwStart = GetTickCount();
	dwNext = dwStart + 1;
	for (i = 0; i < 100; i++) {
		do {
			dwNow = GetTickCount();
		} while (dwNow < dwNext);
		dwNext = dwNow + 1;
	}
	printf("GetTickCount=%u(ms)\n", dwNow - dwStart);

dwStart = timeGetTime();
	dwNext = dwStart + 1;
	for (i = 0; i < 100; i++) {
		do {
			dwNow = timeGetTime();
		} while (dwNow < dwNext);
		dwNext = dwNow + 1;
	}
	printf("timeGetTime=%u(ms)\n", dwNow - dwStart);

if (timeGetDevCaps(&tc, sizeof(TIMECAPS)) != TIMERR_NOERROR) {
		fprintf(stderr, "error: timeGetDevCaps\n");
		return 1;
	}
	printf("tc.wPeriodMin=%u\n", tc.wPeriodMin);
	printf("tc.wPeriodMax=%u\n", tc.wPeriodMax);

timeBeginPeriod(tc.wPeriodMin);
	dwStart = timeGetTime();
	dwNext = dwStart + 1;
	for (i = 0; i < 100; i++) {
		do {
			dwNow = timeGetTime();
		} while (dwNow < dwNext);
		dwNext = dwNow + 1;
	}
	timeEndPeriod(tc.wPeriodMin);
	printf("timeGetTime=%u(ms)\n", dwNow - dwStart);

return 0;
}

GetTickCount=1562(ms)
timeGetTime=1562(ms)
tc.wPeriodMin=1
tc.wPeriodMax=1000000
timeGetTime=129(ms)