title: Release 0.42 short-description: Release notes for 0.42 ...
Creating distribution tarballs can now be made out of projects based on Mercurial. As before, this remains possible only with the Ninja backend.
Meson will now check the keyword arguments used when calling any function and print a warning if any of the keyword arguments is not known. In the future this will become a hard error.
The Vala compiler has an alternative syntax, Genie, that uses the .gs file extension. Meson now recognises and uses Genie files.
The Pkgconfig module object can add arbitrary extra cflags to the Cflags value in the .pc file, using the “extra_cflags” keyword:
pkg.generate(libraries : libs, subdirs : h, version : '1.0', name : 'libsimple', filebase : 'simple', description : 'A simple demo library.', extra_cflags : '-Dfoo' )
Base options are now accessible via the get_option() function.
uses_lto = get_option('b_lto')
Rust targets now take an optional rust_crate_type keyword, allowing you to set the crate type of the resulting artifact. Valid crate types are dylib or cdylib for shared libraries, and rlib or staticlib for static libraries. For more, see Rust's linkage reference.
Both the address- and undefined behavior sanitizers can now be used simultaneously by passing -Db_sanitize=address,undefined to Meson.
A new experimental module to compile code with many different SIMD instruction sets and selecting the best one at runtime. This module is unstable, meaning its API is subject to change in later releases. It might also be removed altogether.
The new keyword implib to executable() allows generation of an import library for the executable.
You can specify build_rpath : '/foo/bar' in build targets and the given path will get added to the target's rpath in the build tree. It is removed during the install step.
Meson will print a warning when the user tries to add an rpath linker flag manually, e.g. via link_args to a target. This is not recommended because having multiple rpath causes them to stomp on each other. This warning will become a hard error in some future release.
Vulkan can now be used as native dependency. The dependency module will detect the VULKAN_SDK environment variable or otherwise try to receive the vulkan library and header via pkgconfig or from the system.
With the Ninja backend it is now possible to limit the maximum number of concurrent linker processes. This is usually only needed for projects that have many large link steps that cause the system to run out of memory if they are run in parallel. This limit can be set with the new backend_max_links option.
By default Meson adds the current source and build directories to the header search path. On some rare occasions this is not desired. Setting the implicit_include_directories keyword argument to false these directories are not used.
MPI is now supported as a dependency. Because dependencies are language-specific, you must specify the requested language with the language keyword, i.e., dependency('mpi', language='c') will request the C MPI headers and libraries. See the MPI dependency for more information.
install_subdirThe [[install_subdir]] command accepts the new exclude_files and exclude_directories keyword arguments that allow specified files or directories to be excluded from the installed subdirectory.
Previously Meson had multiple executables such as mesonintrospect and mesontest. They are now invocable via the main Meson executable like this:
meson configure <arguments> # equivalent to mesonconf <options> meson test <arguments> # equivalent to mesontest <arguments>
The old commands are still available but they are deprecated and will be removed in some future release.
Meson will automatically obtain dependency information for pcap using the pcap-config tool. It is used like any other dependency:
pcap_dep = dependency('pcap', version : '>=1.0')
Most libraries and applications use the same standard templates for glib-mkenums. There is now a new mkenums_simple() convenience method that passes those default templates to glib-mkenums and allows some tweaks such as optional function decorators or leading underscores.