Meson: A Smarter Build System for C++ Projects—A Comprehensive Comparison with CMake and Manual Compilation

When building modern C++ projects, developers have multiple build system options, with CMake being the most widely used. However, there is a newer and more efficient alternative called Meson, designed to provide a faster, simpler, and more streamlined build experience.

This article takes an in-depth look at Meson, highlighting its advantages over CMake, ease of use, drawbacks, comparison with CMake and other build systems, and how it differs from manual compilation.

Why Do We Need Build Systems?

When compiling C++ projects manually, developers often use commands like:

g++ -o my_program main.cpp helper.cpp -I./include -L./lib -lmylib

However, as projects grow in complexity with more files, libraries, and dependencies, managing such commands becomes impractical. Build systems like CMake and Meson simplify and automate the process.

What is Meson?

Meson is a modern build system designed to be fast, simple, and scalable. It uses Python for build configuration and employs easy-to-read setup files (meson.build) instead of complex scripts.

Meson aims to be a more efficient alternative to CMake, reducing unnecessary complexity and improving build speed.

Advantages of Meson Over CMake

1. Faster Build Times

• Meson uses Ninja as its default build backend, making it significantly faster than CMake.

• It avoids unnecessary reconfiguration when modifying code, reducing development time.

2. Simpler and More Readable Configuration

• Meson’s meson.build files are easier to read and write than CMake’s configuration scripts.

• Example of a simple project setup in Meson:

project('my_project', 'cpp')

executable('my_program', 'main.cpp', 'helper.cpp')

In CMake, the equivalent setup is more verbose:

cmake_minimum_required(VERSION 3.10)
project(my_project)

add_executable(my_program main.cpp helper.cpp)

3. Better Integration with External Libraries

• Meson uses pkg-config for finding external libraries, making it more stable and straightforward compared to CMake’s find_package.

• Example of linking an external library in Meson:

mylib = dependency('mylib')
executable('my_program', 'main.cpp', dependencies: mylib)

Whereas in CMake, this requires:

find_package(MyLib REQUIRED)
target_link_libraries(my_program PRIVATE MyLib)

4. Seamless Compiler Support

• Meson supports GCC, Clang, and MSVC without requiring complex configurations.

• Switching between different build environments is easier compared to CMake.

5. Built-in Testing and Profiling Support

• Meson has native support for unit testing and performance analysis, making it easier to manage test cases.

• Example of defining a test in Meson:

test('basic_test', executable('test_program', 'test.cpp'))

In CMake, setting up tests requires additional steps with CTest.

6. A More Consistent and Modern Development Experience

• Meson avoids legacy complexities found in CMake, such as backward compatibility with outdated systems.

• It is Python-based, making it easier to extend than CMake’s custom scripting language.

Drawbacks of Meson Compared to CMake

Despite its advantages, Meson has some limitations that may lead developers to prefer CMake:

1. Less Adoption in Large-Scale Projects

   • CMake remains the dominant choice for massive projects like LLVM and Qt, whereas Meson has yet to gain similar adoption.

2. Fewer Documentation and Learning Resources

   • CMake has been around longer and has a larger community, making it easier to find solutions to problems.

3. No Direct Support for Makefiles

   • Unlike CMake, which can generate Makefiles, Ninja build scripts, and Visual Studio projects, Meson primarily relies on Ninja.

Comparison with Other Build Systems

Manual Compilation vs. Meson and CMake

For small projects, manual compilation using g++ or clang may be sufficient. However, as projects grow, several issues arise:

1. Managing complexity becomes overwhelming with increasing files.

2. Handling external libraries manually is tedious due to dependency resolution issues.

3. No incremental compilation support, leading to unnecessary recompilation of unchanged files.

When to Use Meson

• If you need faster build times and a simpler setup.

• If you are working on medium-sized projects or prefer a modern and efficient approach.

• If you want a lighter alternative to CMake.

When to Use CMake

• If you are working on large-scale projects that require extensive compatibility.

• If you need to generate Makefiles or Visual Studio project files.

• If you require support for legacy systems.

Conclusion

Meson provides a faster and simpler build experience than CMake, making it an excellent choice for developers looking to avoid CMake’s complexity. However, CMake remains the industry standard for large projects due to its extensive ecosystem and compatibility.

If you are looking for a fast, easy-to-learn build system with strong support for external dependencies, Meson is definitely worth exploring!