Calculate the execution time of millisecond

cost_ms.c

/* use ftime() to calculate the execution time of millisecond */
#include <sys/timeb.h>
long timecost(void (*dosomething)())
{
	struct timeb begin, end;
	long cost;

	ftime(&begin);
	dosomething();
	ftime(&end);
	cost = (long)(end.time - begin.time)*1000 + (end.millitm - begin.millitm);
	printf("cost time: %ld ms\n", cost);

	return cost;
}