Using C++ libraries is possible. A way to achieve it is by writing your extension code in C/C++ but ensuring you compile with a C++ compiler. So it will have to be a dynamic shared object. You will need to ensure that all the PHP standard extension functions, including the functions you author, are declared 'extern "C"', and once debugging use apache's error log to see if any ZEND functions you call also need to be modified. Some do; I don't know the basis of which do and don't yet.
It is easiest to begin such a project as a standard extension, very simply, and watch the build process ( do a make ). Grab the compiler commands that operate on the extension, then remove it from PHP's directory tree to a separate location. There configure it to build again. You'll need to change references to where the PHP sources are at the least. After that works, change the compiler from gcc to g++.
