D.4 C, not C++

PuTTY is written entirely in C, not in C++.

We have made some effort to make it easy to compile our code using a C++ compiler: notably, our snew, snewn and sresize macros explicitly cast the return values of malloc and realloc to the target type. (This has type checking advantages even in C: it means you never accidentally allocate the wrong size piece of memory for the pointer type you're assigning it to. C++ friendliness is really a side benefit.)

We want PuTTY to continue being pure C, at least in the platform-independent parts and the currently existing ports. Patches which switch the Makefiles to compile it as C++ and start using classes will not be accepted. Also, in particular, we disapprove of // comments, at least for the moment. (Perhaps once C99 becomes genuinely widespread we might be more lenient.)

The one exception: a port to a new platform may use languages other than C if they are necessary to code on that platform. If your favourite PDA has a GUI with a C++ API, then there's no way you can do a port of PuTTY without using C++, so go ahead and use it. But keep the C++ restricted to that platform's subdirectory; if your changes force the Unix or Windows ports to be compiled as C++, they will be unacceptable to us.