CMakeDeps

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.

Available since: 1.33.0

The CMakeDeps helper will generate one xxxx-config.cmake file per dependency, together with other necessary .cmake files like version, flags and directory data or configuration. It can be used like:

from conan import ConanFile

class App(ConanFile):
    settings = "os", "arch", "compiler", "build_type"
    requires = "hello/0.1"
    generators = "CMakeDeps"

The full instantiation, that allows custom configuration can be done in the generate() method:

from conan import ConanFile
from conan.tools.cmake import CMakeDeps

class App(ConanFile):
    settings = "os", "arch", "compiler", "build_type"
    requires = "hello/0.1"

    def generate(self):
        cmake = CMakeDeps(self)
        cmake.generate()

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 CMakeDeps is a multi-configuration generator, it can correctly create files for Release/Debug configurations to be simultaneously used by IDEs like Visual Studio. In single configuration environments, it is necessary to have a configuration defined, which must be provided via the cmake ... -DCMAKE_BUILD_TYPE=<build-type> argument in command line (Conan will do it automatically when necessary, in the CMake.configure() helper).

There are some attributes you can adjust in the created CMakeDeps object to change the default behavior:

configuration

Allows to define custom user CMake configuration besides the standard Release, Debug, etc ones.

def generate(self):
    deps = CMakeDeps(self)
    # By default, ``deps.configuration`` will be ``self.settings.build_type``
    if self.options["hello"].shared:
        # Assuming the current project ``CMakeLists.txt`` defines the ReleasedShared configuration.
        deps.configuration = "ReleaseShared"
    deps.generate()

build_context_activated

When you have a build-require, by default, the config files (xxx-config.cmake) files are not generated. But you can activate it using the build_context_activated attribute:

tool_requires = ["my_tool/0.0.1"]

def generate(self):
    cmake = CMakeDeps(self)
    # generate the config files for the tool require
    cmake.build_context_activated = ["my_tool"]
    cmake.generate()

Warning

The build_context_activated feature will fail if no “build” profile is used. This feature only work when using the two host and build profiles.

build_context_suffix

When you have the same package as a build-require and as a regular require it will cause a conflict in the generator because the file names of the config files will collide as well as the targets names, variables names etc.

For example, this is a typical situation with some requirements (capnproto, protobuf…) that contain a tool used to generate source code at build time (so it is a build_require), but also providing a library to link to the final application, so you also have a regular require. Solving this conflict is specially important when we are cross-building because the tool (that will run in the building machine) belongs to a different binary package than the library, that will “run” in the host machine.

You can use the build_context_suffix attribute to specify a suffix for a requirement, so the files/targets/variables of the requirement in the build context (tool require) will be renamed:

tool_requires = ["my_tool/0.0.1"]
requires = ["my_tool/0.0.1"]

def generate(self):
    cmake = CMakeDeps(self)
    # generate the config files for the tool require
    cmake.build_context_activated = ["my_tool"]
    # disambiguate the files, targets, etc
    cmake.build_context_suffix = {"my_tool": "_BUILD"}
    cmake.generate()

Warning

The build_context_suffix feature will fail if no “build” profile is used. This feature only work when using the two host and build profiles.

build_context_build_modules

Also there is another issue with the build_modules. As you may know, the recipes of the requirements can declare a cppinfo.build_modules entry containing one or more .cmake files. When the requirement is found by the cmake find_package() function, Conan will include automatically these files.

By default, Conan will include only the build modules from the host context (regular requires) to avoid the collision, but you can change the default behavior.

Use the build_context_build_modules attribute to specify require names to include the build_modules from tool_requires:

tool_requires = ["my_tool/0.0.1"]

def generate(self):
    cmake = CMakeDeps(self)
    # generate the config files for the tool require
    cmake.build_context_activated = ["my_tool"]
    # Choose the build modules from "build" context
    cmake.build_context_build_modules = ["my_tool"]
    cmake.generate()

Warning

The build_context_build_modules feature will fail if no “build” profile is used. This feature only work when using the two host and build profiles.

Properties

The following properties affect the CMakeDeps generator:

  • cmake_file_name: The config file generated for the current package will follow the <VALUE>-config.cmake pattern, so to find the package you write find_package(<VALUE>).
  • cmake_target_name: Name of the target to be consumed.
  • cmake_target_aliases: List of aliases that Conan will create for an already existing target.
  • cmake_find_mode: Defaulted to config. Possible values are:
    • config: The CMakeDeps generator will create config scripts for the dependency.
    • module: Will create module config (FindXXX.cmake) scripts for the dependency.
    • both: Will generate both config and modules.
    • none: Won’t generate any file. It can be used, for instance, to create a system wrapper package so the consumers find the config files in the CMake installation config path and not in the generated by Conan (because it has been skipped).
  • cmake_module_file_name: Same as cmake_file_name but when generating modules with cmake_find_mode=module/both. If not specified it will default to cmake_file_name.
  • cmake_module_target_name: Same as cmake_target_name but when generating modules with cmake_find_mode=module/both. If not specified it will default to cmake_target_name.
  • cmake_build_modules: List of .cmake files (route relative to root package folder) that are automatically included when the consumer run the find_package(). This property can’t be declared in a component, do it in the global self.cpp_info.
  • cmake_set_interface_link_directories: boolean value that should be only used by dependencies that don’t declare self.cpp_info.libs but have #pragma comment(lib, "foo") (automatic link) declared at the public headers. Those dependencies should add this property to their conanfile.py files at root cpp_info level (components not supported for now).

Example:

def package_info(self):
    ...
    # MyFileName-config.cmake
    self.cpp_info.set_property("cmake_file_name", "MyFileName")
    # Names for targets are absolute, Conan won't add any namespace to the target names automatically
    self.cpp_info.set_property("cmake_target_name", "Foo::Foo")

    # Create a new target "MyFooAlias" that is an alias to the "Foo::Foo" target
    self.cpp_info.set_property("cmake_target_aliases", ["MyFooAlias"])
    # The property "cmake_build_modules" can't be declared in a component, do it in self.cpp_info
    self.cpp_info.set_property("cmake_build_modules", [os.path.join("lib", "mypkg.cmake")])

    self.cpp_info.components["mycomponent"].set_property("cmake_target_name", "Foo::Var")

    # Create a new target "VarComponent" that is an alias to the "Foo::Var" component target
    self.cpp_info.components["mycomponent"].set_property("cmake_target_aliases", ["VarComponent"])

    # Skip this package when generating the files for the whole dependency tree in the consumer
    # note: it will make useless the previous adjustements.
    # self.cpp_info.set_property("cmake_find_mode", "none")

    # Generate both MyFileNameConfig.cmake and FindMyFileName.cmake
    self.cpp_info.set_property("cmake_find_mode", "both")

Disable CMakeDeps For Installed CMake configuration files

Some projects may want to disable the CMakeDeps generator for downstream consumers. This can be done by settings cmake_find_mode to none. If the project wants to provide it’s own configuration targets, it should append them to the buildirs attribute of cpp_info.

This method is intended to work with downstream consumers using the CMakeToolchain generator, which will be populated with the builddirs attribute.

Example:

def package(self):
    ...
    cmake.install()

def package_info(self):
    self.cpp_info.set_property("cmake_find_mode", "none") # Do NOT generate anyfiles
    self.cpp_info.builddirs.append(os.path.join("lib", "cmake", "foo"))