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Date: Mon, 10 Jul 2006 10:00:37 -0700
From: "Joshua Hudson" <joshudson@gmail.com>
To: linux-kernel@vger.kernel.org
Subject: Re: [OT] 'volatile' in userspace
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>
> So this would tend to confirm the rule of thumb: use of "volatile" in
> a userspace progam tends to indicate a bug.
>
>                                                 - Ted

No. vfork(), setjmp(), signal().

Yes, I use vfork. So far, the only way I have found for the parent to
know whether or not the child's exec() failed is this way:

volatile int failed;
pid_t pid;

failed = 0;
if (0 == (pid = vfork())) {
   execve(argv[0], argv, envp);
   failed = errno;
   _exit(0);
}
if (pid < 0) {
   /* can't fork */
}
if (failed) {
   /* wait for pid (clean up zombie) */
   errno = failed;
   /* can't exec: update state */
}