C++ – Platform C Preprocessor Definitions

The problem you describe can be solved by defining the template in the header, or via the approach you describe above.

I recommend reading the following points from the C++ FAQ Lite:

• Why can’t I separate the definition of my templates class from its declaration and put it inside a .cpp file?
• How can I avoid linker errors with my template functions?
• How does the C++ keyword export help with template linker errors?

They go into a lot of detail about these (and other) template issues.

Here are a couple of reasons for having different naming of C vs C++ headers:

• Automatic code formatting, you might have different guidelines for formatting C and C++ code. If the headers are separated by extension you can set your editor to apply the appropriate formatting automatically
• Naming, I've been on projects where there were libraries written in C and then wrappers had been implemented in C++. Since the headers usually had similar names, i.e. Feature.h vs Feature.hpp, they were easy to tell apart.
• Inclusion, maybe your project has more appropriate versions available written in C++ but you are using the C version (see above point). If headers are named after the language they are implemented in you can easily spot all the C-headers and check for C++ versions.

Remember, C is not C++ and it can be very dangerous to mix and match unless you know what you are doing. Naming your sources appropriately helps you tell the languages apart.