On Tue, Jun 05, 2007 at 03:30:47PM -0700, Christopher Cramer wrote:
> Jon Harrop:
> > I believe the performance relies upon the Linux kernel lazily copying
> > the process. Does OSX also do that? 
> 
> It's called copy-on-write and I would be surprised if OSX didn't also
> do it.
> 
> The only way to start a new process is to fork, so even if you're just
> running another program you fork first, and then replace the process
> image with the new program with exec. If the fork had to copy the entire
> process image before just throwing it away upon exec, I think Unix,
> which is based around a philosophy of piping between multiple processes,
> would have abandoned fork a long time ago. Then again, there is vfork,
> so I guess they almost did abandon it at one point.
> 
[...]

vfork is only (!!!) for a fork-exec combination.

So, be aware: do not use vfork, if you don't exec right after it!


Ciao,
   Oliver