.c vs .cc vs. .cpp vs .hpp vs .h vs .cxx [duplicate]

by

Historically, the first extensions used for C++ were .c and .h, exactly like for C. This caused practical problems, especially the .c which didn’t allow build systems to easily differentiate C++ and C files.

Unix, on which C++ has been developed, has case sensitive file systems. So some used .C for C++ files. Other used .c++, .cc and .cxx. .C and .c++ have the problem that they aren’t available on other file systems and their use quickly dropped. DOS and Windows C++ compilers tended to use .cpp, and some of them make the choice difficult, if not impossible, to configure. Portability consideration made that choice the most common, even outside MS-Windows.

Headers have used the corresponding .H, .h++, .hh, .hxx and .hpp. But unlike the main files, .h remains to this day a popular choice for C++ even with the disadvantage that it doesn’t allow to know if the header can be included in C context or not. Standard headers now have no extension at all.

Additionally, some are using .ii, .ixx, .ipp, .inl for headers providing inline definitions and .txx, .tpp and .tpl for template definitions. Those are either included in the headers providing the definition, or manually in the contexts where they are needed.

Compilers and tools usually don’t care about what extensions are used, but using an extension that they associate with C++ prevents the need to track out how to configure them so they correctly recognize the language used.

2017 edit: the experimental module support of Visual Studio recognize .ixx as a default extension for module interfaces, clang++ is recognizing .c++m, .cppm and .cxxm for the same purpose.

More Related Contents:

  1. ‘clrscr()’ and ‘conio.h’ not working
  2. Why have header files and .cpp files? [closed]
  3. “using namespace” in c++ headers [duplicate]
  4. What should go into an .h file?
  5. C++ code file extension? What is the difference between .cc and .cpp [closed]
  6. multiple definition in header file
  7. How to read a CMake Variable in C++ source code
  8. Difference between iostream and iostream.h
  9. using namespace std; in a header file
  10. How can a C++ header file include implementation?
  11. How to create two classes in C++ which use each other as data?
  12. C/C++ header and implementation files: How do they work?
  13. List of standard header files in C and C++
  14. Tools to find included headers which are unused? [closed]
  15. Is it a good practice to define C++ functions inside header files? [duplicate]
  16. Is #pragma once part of the C++11 standard?
  17. Can I write C++ code without headers (repetitive function declarations)?
  18. Including C headers inside a C++ program
  19. Which headers in the C++ standard library are guaranteed to include another header?
  20. Is the backslash acceptable in C and C++ #include directives?
  21. Writing function definition in header files in C++
  22. multiple definition error c++
  23. Pros & Cons of putting all code in Header files in C++?
  24. Default member values best practice
  25. Is is a good practice to put the definition of C++ classes into the header file?
  26. Should I include stddef.h or cstddef for size_t
  27. Eclipse CDT: Unresolved inclusion of stl header
  28. Can you start a class name with a numeric digit?
  29. Why is there no multiple definition error when you define a class in a header file?
  30. How do I include the string header?

Leave a Comment