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Date: Wed, 7 Jun 2000 16:31:25 -0400
Message-Id: <200006072031.QAA17014@envy.delorie.com>
From: DJ Delorie <dj AT delorie DOT com>
To: elliot AT lexra DOT com
CC: cygwin AT sourceware DOT cygnus DOT com
In-reply-to: <000601bfd0b7$2a3a0020$0e08a8c0@lexra.com> (elliot@lexra.com)
Subject: Re: mmap() for shared memory?
References:  <000601bfd0b7$2a3a0020$0e08a8c0 AT lexra DOT com>


> I'm trying to implement a good-performance IPC using mmap.  When I
> write to mmap'ed memory in one process, the second process never
> sees the change.

Where are you getting the memory from?  mmap has to be given something
to map - it doesn't create memory out of thin air.  Normally you give
it an open file to map; the only "empty" file is /dev/zero and that's
not shared anyway.

> Perhaps someone can suggest the optimal IPC mechanism under Cygwin.

The optimal IPC is, well, IPCs, stuff like shmget().  Unfortunately,
cygwin doesn't support those.

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