The syntax of Meson's build description files (the Meson language) borrows from Python, but is not Python: It is designed such that it can be reimplemented in any other language;[7] for example, muon[8] is a C implementation and Meson++[9] is a C++ implementation – the dependency on Python is an implementation detail.
The Meson language is intentionally not Turing complete, and can therefore not express an arbitrary program.[7] Instead, arbitrary build steps beyond compiling supported languages can be represented as custom targets.
The Meson language is strongly typed, such that builtin types like library, executable, string, and lists thereof, are non-interchangeable.[10] In particular, unlike Make, the list type does not split strings on whitespace.[7] Thus, whitespace and other characters in filenames and program arguments are handled cleanly.
Meson
CMake
Make
Datatypes
Yes
No
No
List datatype
Yes
semicolon delimited string
whitespace delimited string
Dictionary datatype
since 0.47.0
No
No
File globbing
No
Yes
Yes
Extensible via custom functions
No
Yes
Yes
Can read output of arbitrary commands (at configure time)
run_command
Yes
Yes
Can run arbitrary commands at build time as recipes of custom targets
Yes
Yes
Yes
Speed and correctness
As with any typical buildsystem, correct incremental builds is the most significant speed feature (because all incremental progress is discarded whenever the user is forced to do a clean build).
Unlike bare Make, the separate configure step ensures that changes to arguments, environment variables and command output are not partially applied in subsequent builds, which would lead to a stale build.
Like Ninja, Meson does not support globbing of source files.[7] By requiring all source files to be listed in the build definition files, the build definition file timestamps are sufficient to determine if the set of source files has changed, thereby ensuring that removed source files are detected. CMake supports globbing, but recommends against it for the same reason.[11]
Meson uses ccache automatically if installed. It also detects changes to symbol tables of shared libraries to skip relinking executables against the library when there are no ABI changes. Precompiled headers are supported, but requires configuration. Debug builds are without optimization by default.
A stated goal of Meson is to facilitate modern development practices. As such, Meson knows how to do unity builds, build with test coverage, link time optimization etc without the programmer having to write support for this.
Meson
CMake
Autotools
Generate a configure script
No
No
make dist
Set correct library installation directory on x86_64 Unix
Automatic
Not standardized
./configure --libdir=/usr/lib64
Subprojects
Meson can automatically find and use external dependencies via pkg-config, CMake, and project-specific lookups,[15] but this only finds installed dependencies, which Meson can not do anything about.
Alternatively, or as a fallback, a dependency can be provided as a subproject – a Meson project within another, either contained or as a download link, possibly with patches.[16] This lets Meson resolve dependency hell for the convenience of casual users who want to compile the project, but may contribute to software bloat if a common installed dependency could have been used instead. The mode favored by Linux packagers is therefore fallback.[17]
Meson supports Meson and CMake subprojects. A Meson build file may also refer to the WrapDB service.[16]
Comparison of dependency resolution use cases in different build systems
Cross compilation requires extra configuration, which Meson supports in the form of a separate cross file, which can be external to the Meson project.[19]
GNOME has made it a goal to port its projects to Meson.[20] As of late 2017, GNOME Shell itself exclusively requires Meson after abandoning Autotools,[21] and central components like GTK+, Clutter-GTK, GLib and GStreamer can be built with Meson.[20]
Many freedesktop.org projects have switched to Meson. Systemd relies on Meson since dropping Autotools in version 234,[22] and also X.Org[23] and Mesa[24] were ported to Meson.
Meson's support for Fortran and Cython was improved to help various scientific projects in their switch from setuptools to Meson, for example SciPy.[25] Meson can also be used as a PEP517 backend to build Python wheels, via the meson-python package.[26]
Other notable projects using Meson include QEMU and PostgreSQL; the Meson homepage lists further projects using Meson.[27]
^"High productivity build system". Meson aims to optimize programmer productivity by providing simple, out-of-the-box support for modern software development tools and practices, such as unit tests, coverage reports, Valgrind, CCache and the like.
^"CMake FILE command". Note: We do not recommend using GLOB to collect a list of source files from your source tree. If no CMakeLists.txt file changes when a source is added or removed, the generated build system cannot know when to ask CMake to regenerate.
^"Non-recursive Make Considered Harmful"(PDF). Microsoft. Recursive Make is considered harmful for very good reasons (Miller 1998); it is not possible to accurately track dependencies when the build system is constructed of separate components that invoke each other.
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/ 13 February 2024