Mail Archives: cygwin/2002/08/06/03:54:06
On Tue, Aug 06, 2002 at 05:44:20AM +0200, Juergen Buchmueller wrote:
> It actually seems to be the mmap() implementation which is giving me troubles.
> [...]
> Now the first mmap() region seems to work fine and how I expected -- just as
> it works under *nix, too. The 'sibling' child processes can write to each
> other's memory. However, as soon as any child writes to the second anon +
> shared mmap() region, the Windows memory usage goes up by an amount which
> (exactly!?) matches the size of that region -- BTW: this is something like
> 600KB.
> [...]
> Is there a hidden hierarchy in CYGWIN's mmap() implementation? Or with other
> words, is writing to an anon + shared mmap()ed region from a sibling process
> that is not a direct descendant of the parent that created a memory map, but
> rather a child of another process created by a uber-parent which already
> exited, something that should work?
In theory, it should. In theory.
Could you run `strace -f' and look if there's
> I must admit that I am confused by my own code right now and even more by the
> mmap.cc code and comments. I'm not an experienced multi process + daemon
> author either. For now I sticked up, because crashing OSes make me sick ;-)
Please, could you try to create a simple testcase which exhibits that
behaviour? Oh and, could you please tell which OS you're using?
I'm really trying hard to get a mmap() implementation which is as U*X
like as possible. A simple testcase could help a lot.
> [2] I guess you know the fork2() stuff. It is described at e.g.
> http://www.erlenstar.demon.co.uk/unix/faq_toc.html#TOC88
No, I didn't know that stuff. Did you try to change your implementation
so that you use fork() and really wait() for the children?
Corinna
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Corinna Vinschen Please, send mails regarding Cygwin to
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