Verdigris
A header-only library enabling Qt development without the MetaObject Compiler (moc) using compile-time macros.
What is Verdigris?
Verdigris is a header-only C++ library that allows developers to use Qt without the MetaObject Compiler (moc). It replaces Qt's moc-specific macros with its own set, generating QMetaObject data at compile-time while maintaining full binary compatibility with Qt. This solves build system complexities and enables advanced C++ features like templated QObjects.
C++ developers working with Qt who face build system integration challenges, need templated QObjects, or want to avoid moc's limitations. Particularly useful for projects using non-Qt build systems or requiring advanced metaprogramming.
Developers choose Verdigris because it eliminates moc dependency, simplifies builds, and extends Qt with features like templated QObjects—all while remaining fully compatible with existing Qt libraries and tooling.
Overview
Qt without moc: set of macros to use Qt without needing moc
Use Cases
Best For
- Integrating Qt into projects with non-Qt build systems
- Using templated QObjects in Qt applications
- Simplifying build processes by removing moc steps
- Developing Qt applications with advanced C++ metaprogramming
- Reducing runtime memory overhead for Qt meta-objects
- Maintaining Qt compatibility while avoiding moc limitations
Not Ideal For
- Projects using Qt6's QML_ELEMENT feature for automatic QObject registration in QML
- Teams requiring active, ongoing library maintenance and updates for new Qt versions
- Applications relying on Qt's plugin system with Q_PLUGIN_METADATA
- Developers stuck on C++ standards older than C++14 or unsupported compilers
Pros & Cons
Pros
Eliminates the need for Qt's moc, simplifying integration with non-Qt build systems like CMake or custom setups, as evidenced by the ISOTRONIC GmbH testimonial where migration took only a day.
Maintains complete compatibility with existing Qt libraries and tooling, ensuring seamless interoperability without breaking legacy code or dependencies.
Enables templated QObjects and nested QObject declarations, which are not supported by standard Qt's moc, as highlighted in the status section for extended functionality.
Generates QMetaObject data at compile-time, reducing runtime memory and initialization overhead compared to runtime alternatives like CopperSpice.
Cons
The project is no longer actively maintained, with the author moving on to other projects, posing risks for bug fixes, security updates, and compatibility with future Qt releases.
Missing key Qt features such as Q_PLUGIN_METADATA and QML_ELEMENT, limiting use in plugin-based or modern QML applications, as admitted in the README.
Q_ENUM functionality requires manually repeating the names of every enum value, adding boilerplate code and potential for errors compared to standard Qt.
Requires C++14 and specific compiler support (e.g., GCC 5.1, Clang 3.5, MSVC 2017), excluding older toolchains and adding complexity for heterogeneous development environments.
Frequently Asked Questions
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