1、C语言的nanosleep【1】

pause execution for a specified time

int nanosleep(const struct timespec *req, struct timespec *rem);

2、lstat - get file status

int fstat(int filedes, struct stat *buf);

3、unlink【2】

delete a name and possibly the file it refers to

int unlink(const char *pathname);

参考

【1】

【2】