sig_talk.c

/* sig_talk.c --- Example of how 2 processes can talk */
/* to each other using kill() and signal() */
/* We will fork() 2 process and let the parent send a few */
/* signals to it`s child  */

/* acc sig_talk.c -o sig_talk  on SUNS */
/* c89 sig_talk.c -o sig_talk  on DECS */

#include <stdio.h>
#include <signal.h>

void sighup(); /* routines child will call upon sigtrap */
void sigint();
void sigquit();

main()
{ int pid;

  /* get child process */
  
   if ((pid = fork()) < 0) {
        perror("fork");
        exit(1);
    }
    
   if (pid == 0)
     { /* child */
       signal(SIGHUP,sighup); /* set function calls */
       signal(SIGINT,sigint);
       signal(SIGQUIT, sigquit);
       for(;;); /* loop for ever */
     }
  else /* parent */
     {  /* pid hold id of child */
       printf("\nPARENT: sending SIGHUP\n\n");
       kill(pid,SIGHUP);
       sleep(3); /* pause for 3 secs */
       printf("\nPARENT: sending SIGINT\n\n");
       kill(pid,SIGINT);
       sleep(3); /* pause for 3 secs */
       printf("\nPARENT: sending SIGQUIT\n\n");
       kill(pid,SIGQUIT);
       sleep(3);
     }
}

void sighup()

{  signal(SIGHUP,sighup); /* reset signal */
   printf("CHILD: I have received a SIGHUP\n");
}

void sigint()

{  signal(SIGINT,sigint); /* reset signal */
   printf("CHILD: I have received a SIGINT\n");
}

void sigquit()

{ printf("My DADDY has Killed me!!!\n");
  exit(0);
}