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Clang-Format Style Options
:doc:`ClangFormatStyleOptions` describes configurable formatting style options
supported by :doc:`LibFormat` and :doc:`ClangFormat`.
When using :program:`clang-format` command line utility or
``clang::format::reformat(...)`` functions from code, one can either use one of
the predefined styles (LLVM, Google, Chromium, Mozilla, WebKit) or create a
custom style by configuring specific style options.
Configuring Style with clang-format
:program:`clang-format` supports two ways to provide custom style options:
directly specify style configuration in the ``-style=`` command line option or
use ``-style=file`` and put style configuration in the ``.clang-format`` or
``_clang-format`` file in the project directory.
When using ``-style=file``, :program:`clang-format` for each input file will
try to find the ``.clang-format`` file located in the closest parent directory
of the input file. When the standard input is used, the search is started from
the current directory.
The ``.clang-format`` file uses YAML format:
.. code-block:: yaml
key1: value1
key2: value2
# A comment.
An easy way to get a valid ``.clang-format`` file containing all configuration
options of a certain predefined style is:
.. code-block:: console
clang-format -style=llvm -dump-config > .clang-format
When specifying configuration in the ``-style=`` option, the same configuration
is applied for all input files. The format of the configuration is:
.. code-block:: console
-style='{key1: value1, key2: value2, ...}'
Configuring Style in Code
When using ``clang::format::reformat(...)`` functions, the format is specified
by supplying the `clang::format::FormatStyle
Configurable Format Style Options
This section lists the supported style options. Value type is specified for
each option. For enumeration types possible values are specified both as a C++
enumeration member (with a prefix, e.g. ``LS_Auto``), and as a value usable in
the configuration (without a prefix: ``Auto``).
**BasedOnStyle** (``string``)
The style used for all options not specifically set in the configuration.
This option is supported only in the :program:`clang-format` configuration
(both within ``-style='{...}'`` and the ``.clang-format`` file).
Possible values:
* ``LLVM``
A style complying with the `LLVM coding standards
* ``Google``
A style complying with `Google's C++ style guide
* ``Chromium``
A style complying with `Chromium's style guide
* ``Mozilla``
A style complying with `Mozilla's style guide
* ``WebKit``
A style complying with `WebKit's style guide
**AccessModifierOffset** (``int``)
The extra indent or outdent of access modifiers, e.g. ``public:``.
**AlignEscapedNewlinesLeft** (``bool``)
If ``true``, aligns escaped newlines as far left as possible.
Otherwise puts them into the right-most column.
**AlignTrailingComments** (``bool``)
If ``true``, aligns trailing comments.
**AllowAllParametersOfDeclarationOnNextLine** (``bool``)
Allow putting all parameters of a function declaration onto
the next line even if ``BinPackParameters`` is ``false``.
**AllowShortFunctionsOnASingleLine** (``ShortFunctionStyle``)
Dependent on the value, ``int f() { return 0; }`` can be put
on a single line.
Possible values:
* ``SFS_None`` (in configuration: ``None``)
Never merge functions into a single line.
* ``SFS_Inline`` (in configuration: ``Inline``)
Only merge functions defined inside a class.
* ``SFS_All`` (in configuration: ``All``)
Merge all functions fitting on a single line.
**AllowShortIfStatementsOnASingleLine** (``bool``)
If ``true``, ``if (a) return;`` can be put on a single
**AllowShortLoopsOnASingleLine** (``bool``)
If ``true``, ``while (true) continue;`` can be put on a
single line.
**AlwaysBreakBeforeMultilineStrings** (``bool``)
If ``true``, always break before multiline string literals.
**AlwaysBreakTemplateDeclarations** (``bool``)
If ``true``, always break after the ``template<...>`` of a
template declaration.
**BinPackParameters** (``bool``)
If ``false``, a function call's or function definition's parameters
will either all be on the same line or will have one line each.
**BreakBeforeBinaryOperators** (``bool``)
If ``true``, binary operators will be placed after line breaks.
**BreakBeforeBraces** (``BraceBreakingStyle``)
The brace breaking style to use.
Possible values:
* ``BS_Attach`` (in configuration: ``Attach``)
Always attach braces to surrounding context.
* ``BS_Linux`` (in configuration: ``Linux``)
Like ``Attach``, but break before braces on function, namespace and
class definitions.
* ``BS_Stroustrup`` (in configuration: ``Stroustrup``)
Like ``Attach``, but break before function definitions.
* ``BS_Allman`` (in configuration: ``Allman``)
Always break before braces.
* ``BS_GNU`` (in configuration: ``GNU``)
Always break before braces and add an extra level of indentation to
braces of control statements, not to those of class, function
or other definitions.
**BreakBeforeTernaryOperators** (``bool``)
If ``true``, ternary operators will be placed after line breaks.
**BreakConstructorInitializersBeforeComma** (``bool``)
Always break constructor initializers before commas and align
the commas with the colon.
**ColumnLimit** (``unsigned``)
The column limit.
A column limit of ``0`` means that there is no column limit. In this case,
clang-format will respect the input's line breaking decisions within
statements unless they contradict other rules.
**CommentPragmas** (``std::string``)
A regular expression that describes comments with special meaning,
which should not be split into lines or otherwise changed.
**ConstructorInitializerAllOnOneLineOrOnePerLine** (``bool``)
If the constructor initializers don't fit on a line, put each
initializer on its own line.
**ConstructorInitializerIndentWidth** (``unsigned``)
The number of characters to use for indentation of constructor
initializer lists.
**ContinuationIndentWidth** (``unsigned``)
Indent width for line continuations.
**Cpp11BracedListStyle** (``bool``)
If ``true``, format braced lists as best suited for C++11 braced
Important differences:
- No spaces inside the braced list.
- No line break before the closing brace.
- Indentation with the continuation indent, not with the block indent.
Fundamentally, C++11 braced lists are formatted exactly like function
calls would be formatted in their place. If the braced list follows a name
(e.g. a type or variable name), clang-format formats as if the ``{}`` were
the parentheses of a function call with that name. If there is no name,
a zero-length name is assumed.
**DerivePointerBinding** (``bool``)
If ``true``, analyze the formatted file for the most common binding
and use ``PointerBindsToType`` only as fallback.
**ExperimentalAutoDetectBinPacking** (``bool``)
If ``true``, clang-format detects whether function calls and
definitions are formatted with one parameter per line.
Each call can be bin-packed, one-per-line or inconclusive. If it is
inconclusive, e.g. completely on one line, but a decision needs to be
made, clang-format analyzes whether there are other bin-packed cases in
the input file and act accordingly.
NOTE: This is an experimental flag, that might go away or be renamed. Do
not use this in config files, etc. Use at your own risk.
**ForEachMacros** (``std::vector<std::string>``)
A vector of macros that should be interpreted as foreach loops
instead of as function calls.
These are expected to be macros of the form:
FOREACH(<variable-declaration>, ...)
For example: BOOST_FOREACH.
**IndentCaseLabels** (``bool``)
Indent case labels one level from the switch statement.
When ``false``, use the same indentation level as for the switch statement.
Switch statement body is always indented one level more than case labels.
**IndentFunctionDeclarationAfterType** (``bool``)
If ``true``, indent when breaking function declarations which
are not also definitions after the type.
**IndentWidth** (``unsigned``)
The number of columns to use for indentation.
**KeepEmptyLinesAtTheStartOfBlocks** (``bool``)
If true, empty lines at the start of blocks are kept.
**Language** (``LanguageKind``)
Language, this format style is targeted at.
Possible values:
* ``LK_None`` (in configuration: ``None``)
Do not use.
* ``LK_Cpp`` (in configuration: ``Cpp``)
Should be used for C, C++, ObjectiveC, ObjectiveC++.
* ``LK_JavaScript`` (in configuration: ``JavaScript``)
Should be used for JavaScript.
* ``LK_Proto`` (in configuration: ``Proto``)
Should be used for Protocol Buffers
**MaxEmptyLinesToKeep** (``unsigned``)
The maximum number of consecutive empty lines to keep.
**NamespaceIndentation** (``NamespaceIndentationKind``)
The indentation used for namespaces.
Possible values:
* ``NI_None`` (in configuration: ``None``)
Don't indent in namespaces.
* ``NI_Inner`` (in configuration: ``Inner``)
Indent only in inner namespaces (nested in other namespaces).
* ``NI_All`` (in configuration: ``All``)
Indent in all namespaces.
**ObjCSpaceAfterProperty** (``bool``)
Add a space after ``@property`` in Objective-C, i.e. use
``@property (readonly)`` instead of ``@property(readonly)``.
**ObjCSpaceBeforeProtocolList** (``bool``)
Add a space in front of an Objective-C protocol list, i.e. use
``Foo <Protocol>`` instead of ``Foo<Protocol>``.
**PenaltyBreakBeforeFirstCallParameter** (``unsigned``)
The penalty for breaking a function call after "call(".
**PenaltyBreakComment** (``unsigned``)
The penalty for each line break introduced inside a comment.
**PenaltyBreakFirstLessLess** (``unsigned``)
The penalty for breaking before the first ``<<``.
**PenaltyBreakString** (``unsigned``)
The penalty for each line break introduced inside a string literal.
**PenaltyExcessCharacter** (``unsigned``)
The penalty for each character outside of the column limit.
**PenaltyReturnTypeOnItsOwnLine** (``unsigned``)
Penalty for putting the return type of a function onto its own
**PointerBindsToType** (``bool``)
Set whether & and * bind to the type as opposed to the variable.
**SpaceBeforeAssignmentOperators** (``bool``)
If ``false``, spaces will be removed before assignment operators.
**SpaceBeforeParens** (``SpaceBeforeParensOptions``)
Defines in which cases to put a space before opening parentheses.
Possible values:
* ``SBPO_Never`` (in configuration: ``Never``)
Never put a space before opening parentheses.
* ``SBPO_ControlStatements`` (in configuration: ``ControlStatements``)
Put a space before opening parentheses only after control statement
keywords (``for/if/while...``).
* ``SBPO_Always`` (in configuration: ``Always``)
Always put a space before opening parentheses, except when it's
prohibited by the syntax rules (in function-like macro definitions) or
when determined by other style rules (after unary operators, opening
parentheses, etc.)
**SpaceInEmptyParentheses** (``bool``)
If ``true``, spaces may be inserted into '()'.
**SpacesBeforeTrailingComments** (``unsigned``)
The number of spaces before trailing line comments (//-comments).
This does not affect trailing block comments (/\*\*/-comments) as those
commonly have different usage patterns and a number of special cases.
**SpacesInAngles** (``bool``)
If ``true``, spaces will be inserted after '<' and before '>' in
template argument lists
**SpacesInCStyleCastParentheses** (``bool``)
If ``true``, spaces may be inserted into C style casts.
**SpacesInContainerLiterals** (``bool``)
If ``true``, spaces are inserted inside container literals (e.g.
ObjC and Javascript array and dict literals).
**SpacesInParentheses** (``bool``)
If ``true``, spaces will be inserted after '(' and before ')'.
**Standard** (``LanguageStandard``)
Format compatible with this standard, e.g. use
``A<A<int> >`` instead of ``A<A<int>>`` for LS_Cpp03.
Possible values:
* ``LS_Cpp03`` (in configuration: ``Cpp03``)
Use C++03-compatible syntax.
* ``LS_Cpp11`` (in configuration: ``Cpp11``)
Use features of C++11 (e.g. ``A<A<int>>`` instead of
``A<A<int> >``).
* ``LS_Auto`` (in configuration: ``Auto``)
Automatic detection based on the input.
**TabWidth** (``unsigned``)
The number of columns used for tab stops.
**UseTab** (``UseTabStyle``)
The way to use tab characters in the resulting file.
Possible values:
* ``UT_Never`` (in configuration: ``Never``)
Never use tab.
* ``UT_ForIndentation`` (in configuration: ``ForIndentation``)
Use tabs only for indentation.
* ``UT_Always`` (in configuration: ``Always``)
Use tabs whenever we need to fill whitespace that spans at least from
one tab stop to the next one.
A style similar to the `Linux Kernel style
.. code-block:: yaml
BasedOnStyle: LLVM
IndentWidth: 8
UseTab: Always
BreakBeforeBraces: Linux
AllowShortIfStatementsOnASingleLine: false
IndentCaseLabels: false
The result is (imagine that tabs are used for indentation here):
.. code-block:: c++
void test()
switch (x) {
case 0:
case 1:
case 2:
if (condition)
if (x == y) {
} else if (x > y) {
} else {
A style similar to the default Visual Studio formatting style:
.. code-block:: yaml
UseTab: Never
IndentWidth: 4
BreakBeforeBraces: Allman
AllowShortIfStatementsOnASingleLine: false
IndentCaseLabels: false
ColumnLimit: 0
The result is:
.. code-block:: c++
void test()
switch (suffix)
case 0:
case 1:
case 2:
if (condition)
if (x == y)
else if (x > y)