ClangFormat

ClangFormat is an automated code formatter that is part of the LLVM Clang project. It reformats source code to a consistent style across a codebase and is language aware, with primary support for C, C++, and Objective-C, as well as several other languages supported by clang-format such as Java and JavaScript. Formatting rules are defined in a configuration file named .clang-format (or _clang-format on Windows), using a YAML-based syntax.

Configuration and style options are centralized in the .clang-format file. Users can choose a base style with BasedOnStyle (for example Google, LLVM, WebKit, or Mozilla) and override specific options such as ColumnLimit, IndentWidth, UseTab, BreakBeforeBraces, and many others. If no configuration is found, clang-format applies a default style. The configuration can be placed in the project tree and inherited by files within its directories.

Usage and workflow are straightforward: clang-format can format files in place or emit formatted text to standard output, allowing integration with editors, IDEs, or automated workflows. It is commonly invoked as part of development environments, build systems, or pre-commit checks to enforce a consistent code style across teams.

Integration and ecosystem: clang-format is widely integrated into editors and IDEs (for example VS Code, Vim/Neovim, Emacs, and JetBrains products) and supports various tooling workflows, including continuous integration and code reviews. Its configurability enables teams to maintain a uniform appearance while accommodating project-specific conventions.

History and licensing: clang-format was developed as part of the LLVM project and is distributed under the LLVM project license (Apache 2.0 with LLVM exception). It has become a standard tool for enacting consistent formatting across large codebases.