--- title: Release 0.50.0 short-description: Release notes for 0.50.0 ... # New features ## Added `cmake_module_path` and `cmake_args` to dependency The CMake dependency backend can now make use of existing `Find.cmake` files by setting the `CMAKE_MODULE_PATH` with the new `dependency()` property `cmake_module_path`. The paths given to `cmake_module_path` should be relative to the project source directory. Furthermore the property `cmake_args` was added to give CMake additional parameters. ## Added PGI compiler support Nvidia / PGI C, C++ and Fortran [no-cost](https://www.pgroup.com/products/community.htm) compilers are now supported. They have been tested on Linux so far. ## Fortran Coarray Fortran 2008 / 2018 coarray support was added via `dependency('coarray')` ## Libdir defaults to `lib` when cross compiling Previously `libdir` defaulted to the value of the build machine such as `lib/x86_64-linux-gnu`, which is almost always incorrect when cross compiling. It now defaults to plain `lib` when cross compiling. Native builds remain unchanged and will point to the current system's library dir. ## Native and Cross File Paths and Directories A new `[paths]` section has been added to native and cross files. This can be used to set paths such a prefix and libdir in a persistent way. ## Add warning_level 0 option Adds support for a warning level 0 which does not enable any static analysis checks from the compiler ## A builtin target to run clang-format If you have `clang-format` installed and there is a `.clang-format` file in the root of your master project, Meson will generate a run target called `clang-format` so you can reformat all files with one command: ```meson ninja clang-format ``` ## Added `.path()` method to object returned by `python.find_installation()` `ExternalProgram` objects as well as the object returned by the `python3` module provide this method, but the new `python` module did not. ## Fix ninja console log from generators with multiple output nodes This resolves [issue #4760](https://github.com/mesonbuild/meson/issues/4760) where a generator with multiple output nodes printed an empty string to the console ## `introspect --buildoptions` can now be used without configured build directory It is now possible to run `meson introspect --buildoptions /path/to/meson.build` without a configured build directory. Running `--buildoptions` without a build directory produces the same output as running it with a freshly configured build directory. However, this behavior is not guaranteed if subprojects are present. Due to internal limitations all subprojects are processed even if they are never used in a real Meson run. Because of this options for the subprojects can differ. ## `include_directories` accepts a string The `include_directories` keyword argument now accepts plain strings rather than an include directory object. Meson will transparently expand it so that a declaration like this: ```meson executable(..., include_directories: 'foo') ``` Is equivalent to this: ```meson foo_inc = include_directories('foo') executable(..., include_directories: foo_inc) ``` ## Fortran submodule support Initial support for Fortran `submodule` was added, where the submodule is in the same or different file than the parent `module`. The submodule hierarchy specified in the source Fortran code `submodule` statements are used by Meson to resolve source file dependencies. For example: ```fortran submodule (ancestor:parent) child ``` ## Add `subproject_dir` to `--projectinfo` introspection output This allows applications interfacing with Meson (such as IDEs) to know about an overridden subproject directory. ## Find library with its headers The `find_library()` method can now also verify if the library's headers are found in a single call, using the `has_header()` method internally. ```meson # Aborts if the 'z' library is found but not its header file zlib = find_library('z', has_headers : 'zlib.h') # Returns not-found if the 'z' library is found but not its header file zlib = find_library('z', has_headers : 'zlib.h', required : false) ``` Any keyword argument with the `header_` prefix passed to `find_library()` will be passed to the `has_header()` method with the prefix removed. ```meson libfoo = find_library('foo', has_headers : ['foo.h', 'bar.h'], header_prefix : '#include ', header_include_directories : include_directories('.')) ``` ## NetCDF NetCDF support for C, C++ and Fortran is added via pkg-config. ## Added the Flang compiler [Flang](https://github.com/flang-compiler/flang/releases) Fortran compiler support was added. As with other Fortran compilers, flang is specified using `FC=flang meson ..` or similar. ## New `not_found_message` for `dependency()` You can now specify a `not_found_message` that will be printed if the specified dependency was not found. The point is to convert constructs that look like this: ```meson d = dependency('something', required: false) if not d.found() message('Will not be able to do something.') endif ``` Into this: ```meson d = dependency('something', required: false, not_found_message: 'Will not be able to do something.') ``` Or constructs like this: ```meson d = dependency('something', required: false) if not d.found() error('Install something by doing XYZ.') endif ``` into this: ```meson d = dependency('something', not_found_message: 'Install something by doing XYZ.') ``` Which works, because the default value of `required` is `true`. ## Cuda support Compiling Cuda source code is now supported, though only with the Ninja backend. This has been tested only on Linux for now. Because NVidia's Cuda compiler does not produce `.d` dependency files, dependency tracking does not work. ## `run_command()` accepts `env` kwarg You can pass [[@env]] object to [[run_command]], just like to `test`: ```meson env = environment() env.set('FOO', 'bar') run_command('command', 'arg1', 'arg2', env: env) ``` ## `extract_objects:` accepts `File` arguments The `extract_objects` function now supports File objects to tell it what to extract. Previously, file paths could only be passed as strings. ## Changed the JSON format of the introspection All paths used in the Meson introspection JSON format are now absolute. This affects the `filename` key in the targets introspection and the output of `--buildsystem-files`. Furthermore, the `filename` and `install_filename` keys in the targets introspection are now lists of strings with identical length. The `--target-files` option is now deprecated, since the same information can be acquired from the `--tragets` introspection API. ## Meson file rewriter This release adds the functionality to perform some basic modification on the `meson.build` files from the command line. The currently supported operations are: - For build targets: - Add/Remove source files - Add/Remove targets - Modify a select set of kwargs - Print some JSON information - For dependencies: - Modify a select set of kwargs - For the project function: - Modify a select set of kwargs - Modify the default options list For more information see the rewriter documentation. ## `introspect --scan-dependencies` can now be used to scan for dependencies used in a project It is now possible to run `meson introspect --scan-dependencies /path/to/meson.build` without a configured build directory to scan for dependencies. The output format is as follows: ```json [ { "name": "The name of the dependency", "required": true, "conditional": false, "has_fallback": false } ] ``` The `required` keyword specifies whether the dependency is marked as required in the `meson.build` (all dependencies are required by default). The `conditional` key indicates whether the `dependency()` function was called inside a conditional block. In a real Meson run these dependencies might not be used, thus they _may_ not be required, even if the `required` key is set. The `has_fallback` key just indicates whether a fallback was directly set in the `dependency()` function. ## `introspect --targets` can now be used without configured build directory It is now possible to run `meson introspect --targets /path/to/meson.build` without a configured build directory. The generated output is similar to running the introspection with a build directory. However, there are some key differences: - The paths in `filename` now are _relative_ to the future build directory - The `install_filename` key is completely missing - There is only one entry in `target_sources`: - With the language set to `unknown` - Empty lists for `compiler` and `parameters` and `generated_sources` - The `sources` list _should_ contain all sources of the target There is no guarantee that the sources list in `target_sources` is correct. There might be differences, due to internal limitations. It is also not guaranteed that all targets will be listed in the output. It might even be possible that targets are listed, which won't exist when Meson is run normally. This can happen if a target is defined inside an if statement. Use this feature with care. ## Added option to introspect multiple parameters at once Meson introspect can now print the results of multiple introspection commands in a single call. The results are then printed as a single JSON object. The format for a single command was not changed to keep backward compatibility. Furthermore the option `-a,--all`, `-i,--indent` and `-f,--force-object-output` were added to print all introspection information in one go, format the JSON output (the default is still compact JSON) and force use the new output format, even if only one introspection command was given. A complete introspection dump is also stored in the `meson-info` directory. This dump will be (re)generated each time meson updates the configuration of the build directory. Additionlly the format of `meson introspect target` was changed: - New: the `sources` key. It stores the source files of a target and their compiler parameters. - New: the `defined_in` key. It stores the Meson file where a target is defined - New: the `subproject` key. It stores the name of the subproject where a target is defined. - Added new target types (`jar`, `shared module`). ## `meson configure` can now print the default options of an unconfigured project With this release, it is also possible to get a list of all build options by invoking `meson configure` with the project source directory or the path to the root `meson.build`. In this case, Meson will print the default values of all options. ## HDF5 HDF5 support is added via pkg-config. ## Added the `meson-info.json` introspection file Meson now generates a `meson-info.json` file in the `meson-info` directory to provide introspection information about the latest Meson run. This file is updated when the build configuration is changed and the build files are (re)generated. ## New kwarg `install:` for `configure_file()` Previously when using `configure_file()`, you could install the outputted file by setting the `install_dir:` keyword argument. Now, there is an explicit kwarg `install:` to enable/disable it. Omitting it will maintain the old behaviour.