PHP SourceCode Random

The function for rand() should be something like (SEED * A + C) mod M How can I find the values of A, C, and M? And if I find those values, can I predict the next number in the sequence?

I know that I can find the values of these variables in the PHP source code. But after looking around I really cannot find them...

Does anybody know what file it would be in? Or who else I could contact (I've tried email internals@lists.php.net but haven't got a response)

Also I'm doing all this in PHP versions prior to 7, where rand() and mt_rand() became synonymous.

Thank you!