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Organization: The Man from S.P.U.D.
Date: Mon, 28 Feb 2005 07:37:11 -0600
Message-ID: <2005022807371112877%drbob@TheManFromSPUDcom>
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Subject: How to embed PHP5 into multi-threaded C app?
From: drbob@TheManFromSPUD.com (Bob Beaty)

All,
  I've searched the web for this answer and I'm stumped. I can't find 
the answers. So I thought I'd try the lists. Here goes:
  I have seen how to embed PHP 5 using the code like:

	...
	php_embed_module.ub_write = my_ub_write_func;
	php_embed_module.log_message = my_log_func;
	php_embed_module.sapi_error = my_error_log;
	...
	zend_eval_string(...);
	...

And from this, I looked in the code to see that php_embed_module is a 
static variable that's used in the initialization methods so it *seems* 
as though this can't possibly be thread-safe.
  Yet web servers do it all the time.
  I read on the web that the global variables for the PHP engine are 
maintained in the thread where they were originally defined. This leads 
me to believe that there's the possibility that the php_embed_module 
and other important variables might be thread-local storage, and 
therefore thread-safe.
  Yet if that were the case, how does one define different write, log, 
and error functions so that the engine of one thread does not interfere 
with another?

  In general, my problem is this:
  I have a multi-threaded C++ app that I want to embed the PHP 5 engine 
into. I have read up how to create extensions to PHP, and will do that 
as necessary, but I need to be able to call this engine from my code 
and capture stdout, stderr, etc.
  Can I do this with PHP 5.0.3 as it exists now?
  Are there special things I need to watch out for?
  Any pointers, FAQ sites, etc. that I can look at would be most helpful.
-- 

	Thanks,
		Bob (drbob@TheManFromSPUD.com)
	The Man from S.P.U.D.
	We will write no code before it's designed.