Questions Regarding ZTS and Thread Safe-ness

[NOTE - I just sent a summary of this question. Since it posted immediately, I assume my original post of this from last week was lost. This may provide more detail about my query. Thanks.] I'm new to this list, but I've searched the archives and watched postings and noone's talked (or is talking) about my topic. Not that I saw, anyway! I have an application that will make use of PHP 4.0 scripts in a heavily multithreaded environment. What I want to do is encapsulize PHP in a shared library and have my application load it and pass the scripts to it per thread. I was working with the 4.0 RC's, where the ZTS compiler flag was marked "experimental". Upon getting the 4.0 release, I still see references to "experimental". Questions, Part 1: Are PHP and the Zend engine currently thread-safe? Does defining the ZTS flag create a thread-safe build of v4.0? Is using --enable-experimental-zts still the way to turn this one? (looks like it!) I looked at the code, and my plan was to use the php_execute_script() call in main.c, which seems to be what the apache-module version uses. This is where I first discovered the ZTS #define and how it affects the compiled code. The static-structure version of the PG() and EG() macros certainly can't be thread-safe. Now, here's the bad part. I've tried configuring with --enable-experimental-zts defined, and my build blows out very early with a parameter count error in zendparse(). I see use of macros that equate to nothing with ZTS undefined, then to paramaters when it is, so it looks like there's an issue when defined. So, I guess question #2 is, is anyone compiling and running in thread-safe mode? Any pointers for me? Thanks in advance. If there's a better place to ask these questions, please let me know. "Dev" seemed the most appropriate place to ask. Nick