From owner-freebsd-hackers  Tue Jan 11 21:37:31 2000
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Date: Wed, 12 Jan 2000 00:34:53 -0500 (EST)
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From: Alexander Litvin <archer@lucky.net>
To: "Scott Hess" <scott@avantgo.com>
Cc: hackers@freebsd.org
Subject: Re: rfork() [was: Concept check]
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In-Reply-To: <1d5c01bf5c42$1409d990$1e80000a@avantgo.com>
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In article <1d5c01bf5c42$1409d990$1e80000a@avantgo.com> you wrote:

> You've got that backwards - fork() and vfork() can easily be implemented in
> terms of rfork() [in fact, I believe all three are implemented in terms of
> fork1() in the kernel].  rfork(RFMEM) means that the processes share all
> memory - current AND FUTURE.  You could use minherit() before fork() to
> share current memory, but not future memory.

BTW, concerning rfork(RFMEM). Could somebody explain me, why the
following simple program is coredumping:

#include <stdio.h>
#include <unistd.h>

volatile int data=0;

int
main()
{
   volatile int pid=0;
   int status;

   pid=rfork(RFPROC|RFMEM|RFCFDG);
   if(pid==-1) {
      perror("rfork");
      exit(-1);
   }
   if(pid!=0) {
      wait(&status);
      printf("Data is %d\n",data);
   } else
      data=1;
}

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