New features

Meson 1.6.0 was released on 20 October 2024

Support for OpenXL compiler in AIX.

The OpenXL compiler is now supported from Meson 1.6.0 onwards. So currently, in AIX Operating system we support GCC and openXL compilers for Meson build system.

Both the compilers will archive shared libraries and generate a shared object for a shared module while using Meson in AIX.

alias_target of both_libraries

Previously, when passing a both_libs object to alias_target(), the alias would only point to the shared library. It now points to both the static and the shared library.

Default to printing deprecations when no minimum version is specified.

For a long time, the project() function has supported specifying the minimum meson_version: needed by a project. When this is used, deprecated features from before that version produce warnings, as do features which aren't available in all supported versions.

When no minimum version was specified, meson didn't warn you even about deprecated functionality that might go away in an upcoming semver major release of meson.

Now, meson will treat an unspecified minimum version following semver:

• For new features introduced in the current meson semver major cycle (currently: all features added since 1.0) a warning is printed. Features that have been available since the initial 1.0 release are assumed to be widely available.

• For features that have been deprecated by any version of meson, a warning is printed. Since no minimum version was specified, it is assumed that the project wishes to follow the latest and greatest functionality.

These warnings will overlap for functionality that was both deprecated and replaced with an alternative in the current release cycle. The combination means that projects without a minimum version specified are assumed to want broad compatibility with the current release cycle (1.x).

Projects that specify a minimum meson_version: will continue to only receive actionable warnings based on their current minimum version.

Cargo subprojects is experimental

Cargo subprojects was intended to be experimental with no stability guarantees. That notice was unfortunately missing from documentation. Meson will now start warning about usage of experimental features and future releases might do breaking changes.

This is aligned with our general policy regarding mixing build systems.

Dependencies from CMake subprojects now use only PUBLIC link flags

Any dep obtained from a CMake subproject (or .wrap with method = cmake) now only includes link flags marked in CMake as PUBLIC or INTERFACE. Flags marked as PRIVATE are now only applied when building the subproject library and not when using it as a dependency. This better matches how CMake handles link flags and fixes link errors when using some CMake projects as subprojects.

New built-in option for default both_libraries

both_libraries targets used to be considered as a shared library by default. There is now the default_both_libraries option to change this default.

When default_both_libraries is 'auto', both_libraries() with dependencies that are both_libs themselves will link with the same kind of library. For example, if libA is a both_libs and libB is a both_libs linked with libA (or with an internal dependency on libA), the static lib of libB will link with the static lib of libA, and the shared lib of libA will link with the shared lib of libB.

New as_static and as_shared methods on internal dependencies

dep object returned by declare_dependency() now has .as_static() and .as_shared() methods, to convert to a dependency that prefers the static or the shared version of the linked both_libs target.

When the same dependency is used without those methods, the default_both_libraries option determines which version is used.

Support for DIA SDK

Added support for Windows Debug Interface Access SDK (DIA SDK) dependency. It allows reading with MSVC debugging information (.PDB format). This dependency can only be used on Windows, with msvc, clang or clang-cl compiler.

Support for LLVM-based flang compiler

Added basic handling for the flang compiler that's now part of LLVM. It is the successor of another compiler named flang by largely the same group of developers, who now refer to the latter as "classic flang".

Meson already supports classic flang, and the LLVM-based flang now uses the compiler-id 'llvm-flang'.

nvc and nvc++ now support setting std

The following standards are available for nvc: c89, c90, c99, c11, c17, c18, gnu90, gnu89, gnu99, gnu11, gnu17, gnu18. For nvc++: c++98, c++03, c++11, c++14, c++17, c++20, c++23, gnu++98, gnu++03, gnu++11, gnu++14, gnu++17, gnu++20

Tools can be selected when calling has_tools() on the Qt modules

When checking for the presence of Qt tools, you can now explictly ask Meson which tools you need. This is particularly useful when you do not need lrelease because you are not shipping any translations. For example:

qt6_mod = import('qt6')
qt6_mod.has_tools(required: true, tools: ['moc', 'uic', 'rcc'])

valid tools are moc, uic, rcc and lrelease.

Simple tool to test build reproducibility

Meson now ships with a command for testing whether your project can be built reproducibly. It can be used by running a command like the following in the source root of your project:

meson reprotest --intermediaries -- --buildtype=debugoptimized

All command line options after the -- are passed to the build invocations directly.

This tool is not meant to be exhaustive, but instead easy and convenient to run. It will detect some but definitely not all reproducibility issues.

Support for variable in system dependencies

System Dependency method get_variable() now supports system variable.

test() and benchmark() functions accept new types

test and benchmark now accept ExternalPrograms (as returned by find_program) in the args list. This can be useful where the test executable is a wrapper which invokes another program given as an argument.

test('some_test', find_program('sudo'), args : [ find_program('sh'), 'script.sh' ])

Zig 0.11 can be used as a C/C++ compiler frontend

Zig offers a C/C++ frontend as a drop-in replacement for Clang. It worked fine with Meson up to Zig 0.10. Since 0.11, Zig's dynamic linker reports itself as zig ld, which wasn't known to Meson. Meson now correctly handles Zig's linker.

You can use Zig's frontend via a machine file:

[binaries]
c = ['zig', 'cc']
cpp = ['zig', 'c++']
ar = ['zig', 'ar']
ranlib = ['zig', 'ranlib']
lib = ['zig', 'lib']
dlltool = ['zig', 'dlltool']