sig_p_c.c

Linux大学上机源码学习

#include <stdio.h>
#include<signal.h>
#include <unistd.h>
void waiting(),stop();
int wait_mark;
main()
{
 int p1,p2;
 signal(SIGINT,SIG_DFL);
 signal(SIGQUIT,SIG_IGN);
 while((p1=fork())==-1);
 if(p1>0)
 {   while((p2=fork())==-1);
     if (p2>0)
       {
         wait_mark=1;
         signal(SIGINT,stop);
         waiting();
         kill(p1,16);
         kill(p2,17);
         wait(0);
         wait(0);
         lockf(1,1,0);
         printf("parent process is killed!\n");
         lockf(1,0,0);
         exit(0);        
       }
     else
       {
         wait_mark=1;
         signal(17,stop);
         waiting();
         lockf(1,1,0);
         printf("child process 2 is killed by parnent!\n");
         lockf(1,0,0);
         exit(0);
        }
  }  
else
     {  wait_mark=1;
        signal(16,stop);
        waiting();
        lockf(1,1,0); 
        printf("child 1 is killed\n");
        lockf(1,0,0);
        exit(0);
        
   }
}
void waiting()
  {
    while(wait_mark!=0);
 }
void stop()
   {
     wait_mark=0;
   }