New features (in development)

Added a values() method for dictionaries

Mesons built-in dict type now supports the dict.values() method to retrieve the dictionary values as an array, analogous to the dict.keys() method.

dict = { 'b': 'world', 'a': 'hello' }

dict.keys() # Returns ['a', 'b']
dict.values() # Returns ['hello', 'world']

Add cmd_array method to ExternalProgram

Added a new cmd_array() method to the ExternalProgram object that returns an array containing the command(s) for the program. This is particularly useful in cases like pyInstaller where the Python command is meson.exe runpython, and the full path should not be used but rather the command array.

The method returns a list of strings representing the complete command needed to execute the external program, which may differ from just the full path returned by full_path() in cases where wrapper commands or interpreters are involved.

Microchip XC32 compiler support

The Microchip XC32 compiler is now supported.

Added OS/2 support

Meson now supports OS/2 system. Especially, shortname kwarg and os2_emxomf builtin option are introduced.

shortname is used to specify a short DLL name fitting to a 8.3 rule.

lib = library('foo_library',
    ...
    shortname: 'foo',
    ...
)

This will generate foo.dll not foo_library.dll on OS/2. If shortname is not used, foo_libr.dll which is truncated up to 8 characters is generated.

os2_emxomf is used to generate OMF files with OMF tool-chains.

meson setup --os2-emxomf builddir

This will generate OMF object files and .lib library files. If --os2-emxomf is not used, AOUT object files and .a library files are generated.

Android cross file generator

The env2mfile command now supports a --android argument. When specified, it tells the cross file generator to create cross files for all Android toolchains located on the current machines.

This typically creates many files, so the -o argument specifies the output directory. A typical use case goes like this:

meson env2mfile --android -o androidcross
meson setup --cross-file \
  androidcross/android-29.0.14033849-android35-aarch64-cross.txt \
  builddir

-Db_msvcrt on clang

-Db_msvcrt will now link the appropriate runtime library, and set the appropriate preprocessor symbols, also when the compiler is clang. This is only supported when using link.exe or lld-link.exe as the linker.

Added build_subdir arg to various targets

custom_target(), build_target() and configure_file() now support the build_subdir argument. This directs meson to place the build result within the specified sub-directory path of the build directory.

configure_file(input : files('config.h.in'),
               output : 'config.h',
               build_subdir : 'config-subdir',
               install_dir : 'share/appdir',
               configuration : conf)

This places the build result, config.h, in a sub-directory named config-subdir, creating it if necessary. To prevent collisions within the build directory, build_subdir is not allowed to match a file or directory in the source directory nor contain '..' to refer to the parent of the build directory. build_subdir does not affect the install directory path at all; config.h will be installed as share/appdir/config.h. build_subdir may contain multiple levels of directory names.

This allows construction of files within the build system that have any required trailing path name components as well as building multiple files with the same basename from the same source directory.

Support for Cargo workspaces

When parsing Cargo.toml files, Meson now recognizes workspaces and will process all the required members and any requested optional members of the workspace.

For the time being it is recommended to regroup all Cargo dependencies inside a single workspace invoked from the main Meson project. When invoking multiple different Cargo subprojects from Meson, feature resolution of common dependencies might be wrong.

Experimental Codegen module

A new module wrapping some common code generators has been added. Currently it supports lex/flex and yacc/bison.

Methods from compiler object now accept strings for include_directories

The various compiler methods with a include_directories keyword argument now accept stings or array of strings, in addition to inc objects generated from include_directories() function, as it was already the case for build_target() family of functions.

meson format has a new --check-diff option

When using meson format --check-only to verify formatting in CI, it would previously silently exit with an error code if the code was not formatted correctly.

A new --check-diff option has been added which will instead print a diff of the required changes and then exit with an error code.

-Db_thinlto_cache now supported for GCC

-Db_thinlto_cache is now supported for GCC 15's incremental LTO, as is -Db_thinlto_cache_dir.

Common Cargo.lock for all Cargo subprojects

Whenever Meson finds a Cargo.lock file in the toplevel directory of the project, it will use it to resolve the versions of Cargo subprojects in preference to per-subproject Cargo.lock files. Per-subproject lock files are only used if the invoking project did not have a Cargo.lock file itself.

If you wish to experiment with Cargo subprojects, it is recommended to use cargo to set up Cargo.lock and Cargo.toml files, encompassing all Rust targets, in the toplevel source directory. Cargo subprojects remain unstable and subject to change.

Add a configure log in meson-logs

Add a second log file meson-setup.txt which contains the configure logs displayed on stdout during the meson setup stage. It allows user to navigate through the setup logs without searching in the terminal or the extensive informations of meson-log.txt.

Added new namingscheme option

Traditionally Meson has named output targets so that they don't clash with each other. This has meant, among other things, that on Windows Meson uses a nonstandard .a suffix for static libraries because both static libraries and import libraries have the suffix .lib.

There is now an option namingscheme that can be set to platform. This new platform native naming scheme that replicates what Rust does. That is, shared libraries on Windows get a suffix .dll, static libraries get .lib and import libraries have the name .dll.lib.

We expect to change the default value of this option to platform in a future major version. Until that happens we reserve the right to alter how platform actually names its output files.

Passing -C default-linker-libraries to rustc

When calling rustc, Meson now passes the -C default-linker-libraries option. While rustc passes the necessary libraries for Rust programs, they are rarely enough for mixed Rust/C programs.

rustc will receive -C embed-bitcode=no and -C lto command line options

With this release, Meson passes command line arguments to rustc to enable LTO when the b_lto built-in option is set to true. As an optimization, Meson also passes -C embed-bitcode=no when LTO is disabled; note that this is incompatible with passing -C lto via rust_args.

New method to handle GNU and Windows symbol visibility for C/C++/ObjC/ObjC++

Defining public API of a cross platform C/C++/ObjC/ObjC++ library is often painful and requires copying macro snippets into every projects, typically using __declspec(dllexport), __declspec(dllimport) or __attribute__((visibility("default"))).

Meson can now generate a header file that defines exactly what's needed for all supported platforms: snippets.symbol_visibility_header().

Vala BuildTarget dependency enhancements

A BuildTarget that has Vala sources can now get a File dependency for its generated header, vapi, and gir files.

lib = library('foo', 'foo.vala')
lib_h = lib.vala_header()
lib_s = static_lib('static', 'static.c', lib_h)

lib_vapi = lib.vala_vapi()

custom_target(
  'foo-typelib',
  command : ['g-ir-compiler', '--output', '@OUTPUT@', '@INPUT@'],
  input : lib.vala_gir(),
  output : 'Foo-1.0.typelib'
)

static.c will not start compilation until lib.h is generated.

windows.compile_resources now detects header changes with rc.exe

The rc.exe resource compiler neither provides depfile support nor allows showing includes, as is possible with C or C++ compilers. Therefore, changes to files included by the .rc file did not trigger recompilation of the resource file.

A workaround was added to meson by calling the preprocessor on the .rc file to detect the included headers and adding the result as a dependency to the resource compilation.

i18n.xgettext now accepts CustomTarget and CustomTargetIndex as sources

Previously, custom_tgt were accepted but silently ignored, and custom_idx were not accepted.

Now, they both can be used, and the generated outputs will be scanned to extract translation strings.