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clang-format documentation

llvm-project - GitHub

Configuration in MegaLinter

Variable Description Default value
C_CLANG_FORMAT_ARGUMENTS User custom arguments to add in linter CLI call
Ex: -s --foo "bar"
C_CLANG_FORMAT_COMMAND_REMOVE_ARGUMENTS User custom arguments to remove from command line before calling the linter
Ex: -s --foo "bar"
C_CLANG_FORMAT_FILTER_REGEX_INCLUDE Custom regex including filter
Ex: (src\|lib)
Include every file
C_CLANG_FORMAT_FILTER_REGEX_EXCLUDE Custom regex excluding filter
Ex: (test\|examples)
Exclude no file
C_CLANG_FORMAT_CLI_LINT_MODE Override default CLI lint mode
- file: Calls the linter for each file
- list_of_files: Call the linter with the list of files as argument
- project: Call the linter from the root of the project
C_CLANG_FORMAT_FILE_EXTENSIONS Allowed file extensions. "*" matches any extension, "" matches empty extension. Empty list excludes all files
Ex: [".py", ""]
[".c", ".h"]
C_CLANG_FORMAT_FILE_NAMES_REGEX File name regex filters. Regular expression list for filtering files by their base names using regex full match. Empty list includes all files
Ex: ["Dockerfile(-.+)?", "Jenkinsfile"]
Include every file
C_CLANG_FORMAT_PRE_COMMANDS List of bash commands to run before the linter None
C_CLANG_FORMAT_POST_COMMANDS List of bash commands to run after the linter None
C_CLANG_FORMAT_UNSECURED_ENV_VARIABLES List of env variables explicitly not filtered before calling C_CLANG_FORMAT and its pre/post commands None
C_CLANG_FORMAT_CONFIG_FILE clang-format configuration file nameUse LINTER_DEFAULT to let the linter find it .clang-format
C_CLANG_FORMAT_RULES_PATH Path where to find linter configuration file Workspace folder, then MegaLinter default rules
C_CLANG_FORMAT_DISABLE_ERRORS Run linter but consider errors as warnings false
C_CLANG_FORMAT_DISABLE_ERRORS_IF_LESS_THAN Maximum number of errors allowed 0
C_CLANG_FORMAT_CLI_EXECUTABLE Override CLI executable ['clang-format']

IDE Integration

Use clang-format in your favorite IDE to catch errors before MegaLinter !

IDE Extension Name Install
Visual Studio Code Clang-Format Install in VSCode
Emacs clang-format Visit Web Site

MegaLinter Flavours

This linter is available in the following flavours

Flavor Description Embedded linters Info
all Default MegaLinter Flavor 121 Docker Image Size (tag) Docker Pulls
c_cpp Optimized for pure C/C++ projects 55 Docker Image Size (tag) Docker Pulls

Behind the scenes

How are identified applicable files

  • File extensions: .c, .h

How the linting is performed

  • clang-format is called once with the list of files as arguments (list_of_files CLI lint mode)

Example calls

clang-format --Werror --dry-run myfile.c

Help content

OVERVIEW: A tool to format C/C++/Java/JavaScript/JSON/Objective-C/Protobuf/C# code.

If no arguments are specified, it formats the code from standard input
and writes the result to the standard output.
If <file>s are given, it reformats the files. If -i is specified
together with <file>s, the files are edited in-place. Otherwise, the
result is written to the standard output.

USAGE: clang-format [options] [<file> ...]


Clang-format options:

  --Werror                       - If set, changes formatting warnings to errors
  --Wno-error=<value>            - If set don't error out on the specified warning type.
    =unknown                     -   If set, unknown format options are only warned about.
                                     This can be used to enable formatting, even if the
                                     configuration contains unknown (newer) options.
                                     Use with caution, as this might lead to dramatically
                                     differing format depending on an option being
                                     supported or not.
  --assume-filename=<string>     - Set filename used to determine the language and to find
                                   .clang-format file.
                                   Only used when reading from stdin.
                                   If this is not passed, the .clang-format file is searched
                                   relative to the current working directory when reading stdin.
                                   Unrecognized filenames are treated as C++.
                                     CSharp: .cs
                                     Java: .java
                                     JavaScript: .mjs .js .ts
                                     Json: .json
                                     Objective-C: .m .mm
                                     Proto: .proto .protodevel
                                     TableGen: .td
                                     TextProto: .textpb .pb.txt .textproto .asciipb
                                     Verilog: .sv .svh .v .vh
  --cursor=<uint>                - The position of the cursor when invoking
                                   clang-format from an editor integration
  --dry-run                      - If set, do not actually make the formatting changes
  --dump-config                  - Dump configuration options to stdout and exit.
                                   Can be used with -style option.
  --fallback-style=<string>      - The name of the predefined style used as a
                                   fallback in case clang-format is invoked with
                                   -style=file, but can not find the .clang-format
                                   file to use. Defaults to 'LLVM'.
                                   Use -fallback-style=none to skip formatting.
  --ferror-limit=<uint>          - Set the maximum number of clang-format errors to emit
                                   before stopping (0 = no limit).
                                   Used only with --dry-run or -n
  --files=<filename>             - A file containing a list of files to process, one per line.
  -i                             - Inplace edit <file>s, if specified.
  --length=<uint>                - Format a range of this length (in bytes).
                                   Multiple ranges can be formatted by specifying
                                   several -offset and -length pairs.
                                   When only a single -offset is specified without
                                   -length, clang-format will format up to the end
                                   of the file.
                                   Can only be used with one input file.
  --lines=<string>               - <start line>:<end line> - format a range of
                                   lines (both 1-based).
                                   Multiple ranges can be formatted by specifying
                                   several -lines arguments.
                                   Can't be used with -offset and -length.
                                   Can only be used with one input file.
  -n                             - Alias for --dry-run
  --offset=<uint>                - Format a range starting at this byte offset.
                                   Multiple ranges can be formatted by specifying
                                   several -offset and -length pairs.
                                   Can only be used with one input file.
  --output-replacements-xml      - Output replacements as XML.
  --qualifier-alignment=<string> - If set, overrides the qualifier alignment style
                                   determined by the QualifierAlignment style flag
  --sort-includes                - If set, overrides the include sorting behavior
                                   determined by the SortIncludes style flag
  --style=<string>               - Set coding style. <string> can be:
                                   1. A preset: LLVM, GNU, Google, Chromium, Microsoft,
                                      Mozilla, WebKit.
                                   2. 'file' to load style configuration from a
                                      .clang-format file in one of the parent directories
                                      of the source file (for stdin, see --assume-filename).
                                      If no .clang-format file is found, falls back to
                                      --style=file is the default.
                                   3. 'file:<format_file_path>' to explicitly specify
                                      the configuration file.
                                   4. "{key: value, ...}" to set specific parameters, e.g.:
                                      --style="{BasedOnStyle: llvm, IndentWidth: 8}"
  --verbose                      - If set, shows the list of processed files

Generic Options:

  --help                         - Display available options (--help-hidden for more)
  --help-list                    - Display list of available options (--help-list-hidden for more)
  --version                      - Display the version of this program

Installation on mega-linter Docker image