New features

Added cmake_module_path and cmake_args to dependency

The CMake dependency backend can now make use of existing Find<name>.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 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:

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 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:

executable(..., include_directories: 'foo')

Is equivalent to this:

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:

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.

# 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.

libfoo = find_library('foo',
  has_headers : ['foo.h', 'bar.h'],
  header_prefix : '#include <baz.h>',
  header_include_directories : include_directories('.'))

NetCDF

NetCDF support for C, C++ and Fortran is added via pkg-config.

Added the Flang compiler

Flang 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:

d = dependency('something', required: false)
if not d.found()
  message('Will not be able to do something.')
endif

Into this:

d = dependency('something',
  required: false,
  not_found_message: 'Will not be able to do something.')

Or constructs like this:

d = dependency('something', required: false)
if not d.found()
  error('Install something by doing XYZ.')
endif

into this:

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:

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 --targets 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:

[
  {
    "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.

Additionally 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.