LTTng-Tools Coding Style Author: David Goulet Last Update: 13/11/2012 Tabs VS Spaces: ------------- Right, so our two cents in this endless war! This project uses TABS for one simple reason, the coder can choose whatever size or type his/her indentation is and can set the prefered coding style by replacing the tabs which each normally respected IDE/editor can do. For vim, here is what I used: set shiftwidth=4 set noexpandtab There is one exception for which we use space in this project is for enum, defines and macros values indentation. For instance: Use space to indent the the value so they fit when reading them all. Same goes for the #define below. enum my_enum { value1 = 1, value289 = 289, ... }; #define DEFAULT_VALUE_OF_SOME_SORT 6 #define THE_ANSWER 42 Use space to indent the '\' at the end but tabs at the beginning. #define a_macro(x) \ do { \ fsync(); \ } while (0); \ It's really the only time we use spaces. For everything else, there is TABS! :) Here is a pretty cool vim macro that will highlight your whitespaces and spaces before tab. This helps a *LOT* when coding. " Show trailing whitepace and spaces before a tab: function MyTrail() let no_hl_trail = ["man", "help"] if index(no_hl_trail, &ft) >= 0 return endif syn match ErrorMsg /\s\+$\| \+\ze\t\|\t\+\ze / containedin=@NoTrail endfunction syn cluster NoTrail contains=ALL remove=cComment autocmd Syntax * call MyTrail() C Style: ------------- The coding style used for this project follows the the Linux kernel guide lines, except that brackets "{", "}" should typically be used even for single-line if/else statements. Please refer to: - doc/kernel-CodingStyle.txt (copied from Linux 3.4.4 git tree). - Linux kernel scripts/checkpatch.pl for a script which verify the patch coding style. For header files, please declare the following in this order: 1) #defines - Default values should go in: src/common/defaults.h - Macros used across the project: src/common/macros.h 2) Variables - No _static_ in a header file! This is madness. - Use _extern_ if the global variable is set else where. 3) Function prototype Furthermore, respect the name spacing of files for each non-static symbol visiable outside the scope of the C file. For instance, for the utils.c file in libcommon, every call should be prefixed by "utils_*". Error handling: ------------- We ask to use one single return point in a function. For that, we uses the "goto" statement for the error handling creating one single point for error handling and return code. See the following example: int some_function(...) { int ret; [...] if (ret != 0) { goto error; } [...] error: return ret; } Commenting: ------------- Every function MUST have a comment above it even if the function is trivial. Please add non-trivial comments/documentation as much as you can in the code. Poor comments WILL be rejected upon merging so please pay attention to this details because we do! If the comments requires more than one line, please format like so: /* * Some comments which requires multiple * lines [...] */ and on a single line: /* My comment on a single line. */