#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
#include <time.h>

int main(int argc, char const *argv[])
{
    time_t at = time(NULL);
    char buf[32] = "";
    sprintf(buf, "%d 运行中", getpid());
    write(1, buf, sizeof(buf));
    sleep(2);
    time_t bt = time(NULL);
    printf("\n%d 结束\n", getpid());
    printf("运行时间：%ld 秒\n", bt - at);

    return 0;
}