使用.h 作为 c++ 文件的 header 是否错误？

Question

Is using.h as a header for a c++ file wrong?

I see it all over the place, especially with code written in the "C style". I noticed that Emacs always selects C highlighting style for ah header, but c++ for hpp or hh.

Is it actually "wrong" to label your headers.h or is it just something which annoys me?

EDIT:

There is a good (ish) reason why this annoys me, if I have project files labelled, 'hpp & cpp' I can get away with 'grep something *pp' etc. otherwise I have to type '.h cpp'

Answer 1

nothing wrong with that. This is the default with Microsoft Visual C++.

Just follow the standard you like, and stick with it.

Answer 2

It's not wrong to call your C++ headers.h. There are no rules of what extensions your code must use. For your non-headers, MSVC uses.cpp and on Linux, .cc as well. There is no one global standard, and.h is definitely very widely used.

But I'd say calling your headers.hpp (I've seen.hh a few times as well) is a lot more consistent and informative than just using.h.

Answer 3

You're free to use .h , .H , .hpp , .hxx , .hh , or whathaveyou. Just like you're free to use .c for C sources, and .C , .cpp , .cc , or .cxx for C++ sources. The extension is largely a convention.

Answer 4

It's like with the other files -.c for C, .cpp for C++ - use.h for C, .hpp for C++. This will satisfy most compilers/editors. It's not really wrong to not do so, but it can be used to give a hint which of the both languages you are actually using.

If you want to stop that behaviour without renaming the files, you should have a look at the Emacs config and try to change the source code detection.

Answer 5

Since Emacs has no easy way of finding out whether ah file is C or C++, it's not ridiculous to choose C for.h files and C++ for.hpp files.

Note that all boost header files are suffixed with.hpp.