不可靠信号

#include "io.h"static int flag = 0;void sighandler(int signo){    signal(SIGINT, sighandler);  //它会跳过    printf("test sigint signal\n");    sleep(3);    flag = 1;}int main(int argc, char const *argv[]){    signal(SIGINT, sighandler);    printf("flag:%d\n", flag);    while (!flag) pause();    return 0;}