figc.12

来自「unix环境编程」· 12 代码 · 共 25 行

#include <unistd.h>
#include <time.h>
#include <sys/select.h>

unsigned
sleep(unsigned nsec)
{
	int n;
	unsigned slept;
	time_t start, end;
	struct timeval tv;

	tv.tv_sec = nsec;
	tv.tv_usec = 0;
	time(&start);
	n = select(0, NULL, NULL, NULL, &tv);
	if (n == 0)
		return(0);
	time(&end);
	slept = end - start;
	if (slept >= nsec)
		return(0);
	return(nsec - slept);
}