It would really, really help if you tried to formulate your questions in complete sentences in correct English. I have a rough idea what you are intending to ask, but I'd rather know for sure.
In your case, you should assume that C and C++ are not compatible. Mixing C and C++ (and adding a sprinkling of Objective-C and Objective-C++) will (only) work just fine if you are careful and know what you are doing.