Include What You Use – source analysis tool

Include What You Use is a source analysis tool for C and C++ projects built on Clang.

It checks whether each translation unit directly includes the headers needed for the symbols it uses, helping developers identify unnecessary includes, tighten dependencies, and keep source files more self-contained. The project is intended for integration into existing build workflows and also ships helper scripts for project-wide analysis and automated include cleanup.

This is free and open source software.

Key Features

• Analyzes C and C++ source files to determine which headers should be included for the symbols in use.
• Helps detect superfluous includes so projects can reduce unnecessary header dependencies.
• Can be run on individual source files with normal compiler flags.
• Supports integration with existing build systems by replacing the compiler invocation in batch runs.
• Works with CMake through the CMAKE_CXX_INCLUDE_WHAT_YOU_USE and CMAKE_C_INCLUDE_WHAT_YOU_USE options.
• Includes the iwyu_tool.py helper for running analysis across projects that provide compile commands.
• Ships fix_includes.py to apply recommended include changes automatically.
• Provides Clang version specific branches and release mappings to match the tool with compatible Clang versions.

Website: github.com/include-what-you-use/include-what-you-use
Support:
Developer: include-what-you-use contributors
License: University of Illinois/NCSA Open Source License

Include What You Use is written in C++. Learn C++ with our recommended free books and free tutorials.

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