gflags/gflags

gflags is a C++ library that implements command-line flags processing. The library lets developers define flags directly in source files and handles parsing of standard types like strings and numbers from command-line arguments. It solves the problem of managing application configuration through command-line options by providing a declarative approach where flags can be scattered throughout a codebase rather than centralized in a single location.

Developers choosing gflags should be aware that it is no longer maintained by Google, though it receives minor maintenance releases from the open-source community. The README explicitly recommends that users of Abseil should use Abseil's flags library instead. The tool is suited for C++ projects that need straightforward command-line argument handling without the overhead of a more complex configuration system. Feature additions are not currently planned and depend on community contributions.

The project maintains active build system support across multiple platforms and tools. Recent maintenance releases have added support for Bazel's Bzlmod system and CMake 4.0, improved compatibility with BlackBerry QNX, and migrated CI infrastructure to GitHub Actions. The library continues to address build issues across different compilers and platforms, including Windows and MinGW, and resolves issues flagged by static code analyzers. The project accepts bug reports and community pull requests through its GitHub issue tracker.