如何正确使用SIGALRM？

但它不起作用,只有当我按下CTR-C时,它才会发出“我活着”的消息,我猜
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-Cn");
    printf("I'm running,waiting for a signn");
    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 signaln");
  while (1) {}
  return (0);
}