测试语法颜色显示&&警告signal用法

#include <signal.h>
#include <stdio.h>
#include <unistd.h>
typedef void (*sighandler_t)(int);
sighandler_t sig_hand(int data)
{    
 printf("should not used at here.\n");
 _exit(0);
}

int main(void)
{    
 printf("yes,it is test:\n");
 signal(SIGINT,(sighandler_t)sig_hand);
 int i=0;
 while(1)
 {
         printf("yes,it is test:%d\n",i++);
         sleep(1);
 }
 return 0;
}