Question

我制作了这段代码，我必须使用闹钟信号（SIGALRM）让节目每隔3秒打印一条“我还活着”的信息。

但它不起作用，它会发出信息＆＃34;我活着＆＃34;只有当我按CTR-C时，我才会猜测我没有把SIGALRM功能放在正确的位置，你能帮助我吗？

#include <stdlib.h>
#include <signal.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>

unsigned Count = 0; //Counts the number of times it receives the signal SIGINT.
void mypause(int sign); //prototype of the function my pause.

void mypause(int sign) {
  signal(SIGALRM, mypause); //Set alarm clock for 3 seconds.
  alarm(3);
  printf("I'm Alive");
  signal(SIGINT, mypause);
  switch (sign) {
  case SIGINT:
    printf("\nPressed CTR-C\n");
    printf("I'm running, waiting for a sign\n");
    Count++;
    break;
  case SIGQUIT:
    printf("\nPressed CTR-\\n");
    printf("You pressed CTR-C %d times", Conta);
    exit(0); //Exit program.
    break;
  }
}

int main() {
  signal(SIGALRM, mypause);
  signal(SIGINT, mypause);
  signal(SIGQUIT, mypause);
  printf("\nI'm running waiting for a signal\n");
  while (1) {}
  return (0);
}

Answer 1

也许在alarm(3)中添加main()？

如何正确使用SIGALRM？

1 个答案: