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To: linux-kernel@vger.kernel.org
From: Halesh S <halesh.s@india.com>
Subject: parent process behaviour to signal after vfork()
Date: Tue, 28 Oct 2008 06:43:19 +0000 (UTC)
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Hi,

Please find the below test code...

#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <unistd.h>
int x = 0;
typedef void (*sighandler_t)(int);
void fun()
{
  printf("SIGNAL CAUGHT\n");
}

int main()
{
  int pid;

  signal(SIGINT, (sighandler_t)fun);
  signal(SIGSEGV, (sighandler_t)fun);
  pid = vfork();

  if ( pid == 0 ) {
    printf(" I am child - %d \n", pid);
    x++;
    raise(SIGINT);
    printf("x = %d\n", x);
    exit(0);
  }
  else {
    printf(" I am parent - %d\n", pid);
    raise(SIGSEGV);
    printf("x = %d\n", x);
  }
}

Why the parent process is not able to handle/respond the signals, when a child
once handles the signal, child is created using vfork(). 

In vfork() man page - 
       "Signals to the parent arrive after the child releases the parent's 
       memory."

How to make sure that child has released the parent memory..??

Thanks,
Halesh