MesonDeps

Warning

These tools are still experimental (so subject to breaking changes) but with very stable syntax. We encourage the usage of it to be prepared for Conan 2.0.

MesonToolchain normally works together with PkgConfigDeps to manage all the dependencies, but sometimes we need to gather some flags coming from Autotools tool so that’s what MesonDeps is meant for. In other words, it is typically used when Meson cannot find a dependency using the already known detection mechanisms like: pkg-config, cmake, config-tool, etc. For instance, if we’d have these lines in your meson.build file, you might need MesonDeps to find that dependency and inject the correct flags to the compiler:

meson.build

project('tutorial', 'cpp')
cxx = meson.get_compiler('cpp')
mylib = cxx.find_library('mylib', required: true)
executable('app', 'main.cpp', dependencies: mylib)

In a nutshell, the MesonDeps generator is the dependencies generator for Meson and GNU flags. It creates a conan_meson_deps_flags.ini file with all those flags collected by each dependency.

Important

At this moment, this generator must be used along with MesonToolchain one to make it work correctly.

Important

This class will require very soon to define both the “host” and “build” profiles. It is very recommended to start defining both profiles immediately to avoid future breaking. Furthermore, some features, like trying to cross-compile might not work at all if the “build” profile is not provided.

The MesonDeps generator can be used by name in conanfiles:

conanfile.py

class Pkg(ConanFile):
    generators = "MesonDeps"

conanfile.txt

[generators]
MesonDeps

And it can also be fully instantiated in the conanfile generate() method:

from conan import ConanFile
from conan.tools.meson import MesonDeps

class App(ConanFile):
    settings = "os", "arch", "compiler", "build_type"

    def generate(self):
        tc = MesonDeps(self)
        tc.generate()

The MesonDeps generates after a conan install command a conan_meson_deps_flags.ini file:

[constants]
deps_c_args = []
deps_c_link_args = []
deps_cpp_args = []
deps_cpp_link_args = []

This generator defines a Meson constants: deps_c_args, deps_c_link_args, deps_cpp_args, deps_cpp_link_args, that accumulate all dependencies information, including transitive dependencies, with flags like -I<path>, -L<path>, etc.

Important

Those variables are added automatically as part of the built-in options declared by MesonToolchain generator: c_args, c_link_args, cpp_args, cpp_link_args.

Note

For now, only the requires information is generated, the tool_requires one is not managed by this generator yet.

Attributes

c_args, c_link_args, cpp_args, cpp_link_args: list of flags that accumulate all dependencies information. Each one is saved as deps_c_args, deps_c_link_args, deps_cpp_args, and deps_cpp_link_args, respectively in the conan_meson_deps_flags.ini file.

from conan import ConanFile
from conan.tools.meson import MesonDeps

class App(ConanFile):
    settings = "os", "arch", "compiler", "build_type"

    def generate(self):
        tc = MesonDeps(self)
        tc.c_args.append("-val1")
        tc.c_link_args.append("-val2")
        tc.cpp_args.append("-val3")
        tc.cpp_link_args.append("-val4")
        tc.generate()