shell_exec, environment, and multithreading servers

Hi all, Recently I faced with one funny problem in PHP. Seems there is no way to run a sub-process using shell_exec() (or backticks), and pass there specially crafted environment without affecting all running threads. As soon as I update the environment, all other threads see the change. It's multithreading nature to be running under the same process and share the process environment, no problems so far, but there should be a way to run sub-process with appropriate set of environment variables without affecting all the threads. Looks like for Win32 target, there is a popenex() function that is called by shell_exec and this function has env parameter. I think it makes sense to pass $_ENV in this argument. Certainly, $_ENV should be converted into array of pointers. Not sure if there is any way under unix other than using execXX() instead of popen() to get the same behaviour. Thoughts? -jv