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From Glenn <gs-apache-...@gluelogic.com>
Subject Re: story posted
Date Mon, 10 Feb 2003 00:39:14 GMT
At the risk of inflaming an already tense conversation (too late),
I have to say that third party thread-safety issues are not a very
good excuse.

It's trivial to make a library thread safe by serializing access to the
functions of the non-thread-safe library.  Although scripts that employ
the non-thread-safe library would suffer a performance penalty, they
would still work!

If the core of PHP is thread safe, then this should not be a big deal.
Also, as time goes on, third party library locks can be removed as
thread-safe versions of the libraries become available.

For a well-written and concise explanation, please refer to:
http://www.unet.univie.ac.at/aix/aixprggd/genprogc/writing_reentrant_thread_safe_code.htm

Cheers,
-Glenn

On Fri, Feb 07, 2003 at 02:02:39AM +0100, Sascha Schumann wrote:
> > Rather than fix the TS issues in all the 3rd party libraries
> > that can be used with PHP's and its extension its more
> > pragmatic to sort out thread/filter issues in PHP core.
> 
>     The PHP project has been working on thread-safety since 1999.
>     All core components and most extensions can be compiled in
>     thread-safe mode.
> 
>     The first SAPI module for a threaded UNIX web server was
>     completed in the same year (for AOLserver).
> 
>     It's safe to assert that we need to primarily worry about 3rd
>     party libraries.
> 
> > Also blaming on use of TLS seems a little strange since use of
> > TLS is supposed to improve re-entrancy isn't it ?
> 
>     Let me just quickly define what these concepts refer to.
> 
>     Thread-safe means that you can run code in multiple threads
>     concurrently (e.g. multiple worker threads).
> 
>     Reentrant means that you can run code in a single thread
>     context in a nested way (e.g. Apache sub-requests).
> 
>     Thread local storage aids only the former one.
> 
>     From my point of view we should not worry about reentrancy
>     right now, at least not until we a have firm grasp on the 3rd
>     party TS issues.
> 
>     - Sascha

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