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From "Ralf S. Engelschall" <>
Subject Re: How to share memory between processes?
Date Thu, 20 May 1999 06:45:48 GMT

In article <> you wrote:
> I am new to this mailing list so maybe that's an old hat but is there a
> possibility to share data among the running instances of a module? The
> module I am trying to write has to share a connection pool between the
> processes and the only solution having entered my mind so far is to
> externalize the connection pool in another server :-( Looking through the
> mail-archive I've seen that this problem will probably be addressed in
> Apache 2.0 so maybe somebody has already worked out a better solution?

Currently (Apache 1.3.6/7-dev) there is no easy way to share data between the
pre-forked httpd processes.  People here either use an external file (e.g. DBM
file on disk) or an external common process. The reason is because shared
memory handling is nasty because of portability and Apache's only shared
memory handling is for the scoreboard stuff - but that's not directly useable
for modules. When you really want shared memory, you can either wait for 1.3.7
plus perhaps EAPI or in the meantime link a shared memory library directly
to your module. For this you can for instance use my MM library
( It hides all gory (portability)
details of shared memory handling.
                                       Ralf S. Engelschall

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