Clang Format Text Style

1. Clang-format: ADIOS2 uses the clang-format tool to automatically enforce source code style and formatting rules. There are various ways to integrate the clang-format tool into your IDE / Code Editor depending on if you use Emacs, Vim, Eclipse, KDevelop, Microsoft Visual Studio, etc. that are a bit outside the scope of this document but a quick google search for "integrate clang-format" should point you in the right direction. Main points:
   • Lines no longer than 80 characters.
   • Always use braces { and }, even for 1 line if blocks.
   • Use 4 spaces for indentation.
   • However, you can always reformat the code manually by running:

   • clang-format -i SourceFile.cpp SourceFile.h

2. Naming: Use meaningful English words, well-known acronyms (MPI, XML, CFD, GMRES, etc.), or well-known short names (Config, Comm, 2D, 3D).
   • Examples: initialTime instead of tIni , or work instead of wrk
   • One Exception: when redefining long types with the using keyword reasonable mnemonics and short names are allowed, always document scope.

     // local 2D Vector of doubles  
     using std::vector<std::vector<double>> = vDouble2D;

3. Avoid underscores: adds unnecessary length to the variable name, especially when combined with STL container types, and could conflict with name mangling. Reserve it for prefix of special cases (see class members and lambda functions). Use upper case letters instead.
   • Don't

          std::vector <  std::vector < <  double  > > this_is_my_very_very_long_two_dimensional_vector_name; 

   • Do

          std::vector <  std::vector < <  double  > > thisIsMyVeryVeryLongTwoDimensionalVectorName; 

4. Using and typedef keywords: Prefer the keyword using over typedef for readability. Only rename very long complex or custom types, do not rename standard types ( int , double , std::vector ). Prefer including ADIOSTypes.h as it contains fixed types in the std:: namespace uint8_t, uint64_t .

   • cpp typedef std::vector<std::vector<std::map<std::string, double>>> MapIn2DVector;
   • cpp using std::vector<std::vector<std::map<std::string, double>>> = MapIn2DVector;
   • Do

     •   using    std::vector  <  std::vector  <  std::map  <  std::string , double  > > > = MapIn2DVector;