Clang-format, automatically format source code

Info

clang-format allows you to use a simple text file to define how you want your source to look like and then format it automatically. The configuration file consists of choices, you can only select between prepared variants for prepared cases.

URL

You can get a start here: https://clang.llvm.org/

Debian

For Debian, you are in luck:

sudo apt-get install clang-format

file .clang-format

Then you create ONE .clang-format file which you put in the top most directory of your c++ projects. Once! If you have "work/c++/project-1" and work/c++/project-2" then you put ".clang-format" into "work/c++/".

.clang-format:

---
Language:        Cpp
# BasedOnStyle:  LLVM
AccessModifierOffset: 2
AlignAfterOpenBracket: Align
AlignConsecutiveAssignments: true
AlignConsecutiveDeclarations: true
AlignEscapedNewlines: Left
AlignOperands:   true
AlignTrailingComments: true
AllowAllParametersOfDeclarationOnNextLine: true
AllowShortBlocksOnASingleLine: true
AllowShortCaseLabelsOnASingleLine: true
AllowShortFunctionsOnASingleLine: InlineOnly
AllowShortIfStatementsOnASingleLine: false
AllowShortLoopsOnASingleLine: false
AlwaysBreakAfterDefinitionReturnType: None
AlwaysBreakAfterReturnType: None
AlwaysBreakBeforeMultilineStrings: false
AlwaysBreakTemplateDeclarations: MultiLine
BinPackArguments: true
BinPackParameters: true
BraceWrapping:   
  AfterClass:      true
  AfterControlStatement: true
  AfterEnum:       false
  AfterFunction:   true
  AfterNamespace:  true
  AfterObjCDeclaration: true
  AfterStruct:     true
  AfterUnion:      true
  AfterExternBlock: true
  BeforeCatch:     true
  BeforeElse:      true
  IndentBraces:    true
  SplitEmptyFunction: true
  SplitEmptyRecord: true
  SplitEmptyNamespace: true
BreakBeforeBinaryOperators: NonAssignment
BreakBeforeBraces: Allman
BreakBeforeInheritanceComma: true
BreakInheritanceList: AfterColon
BreakBeforeTernaryOperators: true
BreakConstructorInitializersBeforeComma: true
BreakConstructorInitializers: BeforeComma
BreakAfterJavaFieldAnnotations: false
BreakStringLiterals: true
ColumnLimit:    110 
CommentPragmas:  '^ IWYU pragma:'
CompactNamespaces: false
ConstructorInitializerAllOnOneLineOrOnePerLine: false
ConstructorInitializerIndentWidth: 4
ContinuationIndentWidth: 4
Cpp11BracedListStyle: true
DerivePointerAlignment: false
DisableFormat:   false
FixNamespaceComments: false
ForEachMacros:   
  - foreach
  - Q_FOREACH
  - BOOST_FOREACH
IncludeBlocks:   Preserve
IncludeCategories: 
  - Regex:           '^"(llvm|llvm-c|clang|clang-c)/'
    Priority:        2
  - Regex:           '^(<|"(gtest|gmock|isl|json)/)'
    Priority:        3
  - Regex:           '.*'
    Priority:        1
IncludeIsMainRegex: '(Test)?$'
IndentCaseLabels: false
# with newer clang-format: IndentPPDirectives: BeforeHash
IndentPPDirectives: None
IndentWidth:     4
IndentWrappedFunctionNames: true
JavaScriptQuotes: Leave
JavaScriptWrapImports: true
KeepEmptyLinesAtTheStartOfBlocks: false
MacroBlockBegin: ''
MacroBlockEnd:   ''
MaxEmptyLinesToKeep: 1
NamespaceIndentation: All
ObjCBinPackProtocolList: Auto
ObjCBlockIndentWidth: 4
ObjCSpaceAfterProperty: false
ObjCSpaceBeforeProtocolList: true
PenaltyBreakAssignment: 2
PenaltyBreakBeforeFirstCallParameter: 19
PenaltyBreakComment: 300
PenaltyBreakFirstLessLess: 120
PenaltyBreakString: 1000
PenaltyBreakTemplateDeclaration: 10
PenaltyExcessCharacter: 1000000
PenaltyReturnTypeOnItsOwnLine: 60
PointerAlignment: Left
ReflowComments:  true
SortIncludes:    true
SortUsingDeclarations: true
SpaceAfterCStyleCast: true
SpaceAfterTemplateKeyword: true
SpaceBeforeAssignmentOperators: true
SpaceBeforeCpp11BracedList: true
SpaceBeforeCtorInitializerColon: true
SpaceBeforeInheritanceColon: true
SpaceBeforeParens: ControlStatements
SpaceBeforeRangeBasedForLoopColon: true
SpaceInEmptyParentheses: false
SpacesBeforeTrailingComments: 1
SpacesInAngles:  false
SpacesInContainerLiterals: false
SpacesInCStyleCastParentheses: false
SpacesInParentheses: false
SpacesInSquareBrackets: false
Standard:        Cpp11
TabWidth:        4
UseTab:          Never
...

Makefile

Now you add to your Makefile something like this:

# clang-format
.PHONY: cf
cf:
	@clang-format -style=file -i include/*.h
	@clang-format -style=file -i src/*.cpp
 

Depending on your project you might have only one src directory (and no include directory) or you might even have no src directory).

And then you go to your project, in the example above you would go to work/c++/project-1 and there you call clang-format:

make cf

Misc

Make sure to not mix real code changes and clang-format changes in your history or you will hate yourself. Or others will hate you.