linux中的sleep为库调用(library calls)，其声明文件为unistd.h。

unsigned int sleep(unsigned int seconds);

如果进程或者线程调用sleep请求的休眠的时间seconds过去，那么会返回0；如果休眠期间被信号中断，那么返回剩余的休眠时间。

 

#include 
     
      #include 
      
       #include 
       
        #include 
        
         void sig_handler(int num){    printf("receive %d signal\n", num);} // 在休眠时间20s内，键入中断信号（ctrl+c)int t_main(){    int time = 20;    signal(SIGINT, sig_handler);    printf("enter sleep\n");    sleep(time);    printf("sleep over\n");    return 0;} /*
        
       
      
     

./xsleep

enter sleep

^Creceive 2 signal

sleep over

*/int main(){    int time = 20;    signal(SIGINT, sig_handler);    printf("enter sleep\n");    do{        time = sleep(time);    }while (time > 0);    printf("sleep over\n");    return 0;} /*

./xsleep

enter sleep

^Creceive 2 signal

^Creceive 2 signal

^Creceive 2 signal

^Creceive 2 signal

^Creceive 2 signal

^Creceive 2 signal

^Creceive 2 signal

sleep over

*/