How to configure clang‐format

Overview

clang-format is an utility to format source code in several languages according to predefined settings. Settings for auto-formatting of C++ source files in Kratos are summarized below, and should be saved in .clang-format file in the Kratos root directory. These settings are chosen to closely match the formatting style used in Kratos.

Configuring Editors

Visual Studio Code

Install the C/C++ extension and customize settings.json to include:

"C_Cpp.clang_format_path": "/path/to/<clang-format-executable>",
"C_Cpp.clang_format_style": "file",
"C_Cpp.clang_format_fallbackStyle": "none"

Emacs

Add the line

(load "/path/to/clang-format.el")

to ~/.emacs.d/init.el. Format a source file with M-x clang-format-region.

CLion

• Add the .clang-format file to the Kratos root directory as explained above
• Go to File->Settings->Tools->External Tools and click on the plus sign. A window should pop up. Choose a name, for example "clang-format"
• For the Tool settings tab I'm using this configuration:
  • Program: clang-format (you should use the name of your executable here)
  • Parameters: --style=file -i $FileName$
  • Working directory: $FileDir$

Now, with your file open, you can go to Tools->External tools and run the config above. It basically calls clang-format and does inplace formatting using the style define in the first .clang-format file found in a parent directory.

.clang-format file

(tested with clang-format version 3.5, 3.8)

Language: Cpp  
AccessModifierOffset: -4  
AlignEscapedNewlinesLeft: true  
AlignTrailingComments: true  
AllowAllParametersOfDeclarationOnNextLine: true  
AllowShortBlocksOnASingleLine: false  
AllowShortFunctionsOnASingleLine: None  
AllowShortIfStatementsOnASingleLine: false  
AllowShortLoopsOnASingleLine: false  
AlwaysBreakBeforeMultilineStrings: true  
AlwaysBreakTemplateDeclarations: true  
BinPackParameters: false  
BreakBeforeBinaryOperators: false  
BreakBeforeBraces: Stroustrup  
BreakBeforeTernaryOperators: true  
BreakConstructorInitializersBeforeComma: false  
ColumnLimit: 80  
CommentPragmas: ''  
ConstructorInitializerAllOnOneLineOrOnePerLine: true  
ConstructorInitializerIndentWidth: 4  
ContinuationIndentWidth: 4  
DerivePointerAlignment: false  
DisableFormat: false  
ExperimentalAutoDetectBinPacking: false  
IndentCaseLabels: false  
IndentWidth: 4  
IndentWrappedFunctionNames: false  
IndentFunctionDeclarationAfterType: false  
MaxEmptyLinesToKeep: 1  
KeepEmptyLinesAtTheStartOfBlocks: false  
NamespaceIndentation: None  
PenaltyBreakBeforeFirstCallParameter: 1  
PenaltyBreakComment: 300  
PenaltyBreakString: 1000  
PenaltyBreakFirstLessLess: 120  
PenaltyExcessCharacter: 1  
PenaltyReturnTypeOnItsOwnLine: 1000  
PointerAlignment: Left  
SpaceBeforeAssignmentOperators: true  
SpaceBeforeParens: ControlStatements  
SpaceInEmptyParentheses: false  
SpacesBeforeTrailingComments: 1  
SpacesInAngles: false  
SpacesInCStyleCastParentheses: false  
SpacesInContainerLiterals: true  
SpacesInParentheses: false  
Cpp11BracedListStyle: true  
Standard: Cpp11  
TabWidth: 4  
UseTab: Never