cmake_layout

Warning

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

Available since: 1.45.0

For example, this would implement the standard CMake project layout:

from conan.tools.cmake import cmake_layout

def layout(self):
    cmake_layout(self)

Note

To try it you can use the conan new hello/0.1 --template=cmake_lib template.

The cmake_layout() sets the folders and cpp attributes described in the (layout reference).

The assigned values depend on the CMake generator that will be used. It can be defined with the tools.cmake.cmaketoolchain:generator [conf] entry or passing it in the recipe to the cmake_layout(self, cmake_generator) function. The assigned values are different if it is a multi-config generator (like Visual Studio or Xcode), or a single-config generator (like Unix Makefiles).

These are the values assigned by the cmake_layout:

  • conanfile.folders.source: src_folder argument or . if not specified.
  • conanfile.folders.build:
    • build: if the cmake generator is multi-configuration.
    • build/Debug or build/Release: if the cmake generator is single-configuration, depending on the build_type.
    • The "build" string, can be defined to other value by the build_folder argument.
  • conanfile.folders.generators: build/generators
  • conanfile.cpp.source.includedirs: ["include"]
  • conanfile.cpp.build.libdirs and conanfile.cpp.build.bindirs:
    • ["Release"] or ["Debug"] for a multi-configuration cmake generator.
    • . for a single-configuration cmake generator.
def layout(self):
    cmake_layout(self, src_folder="subfolder", build_folder="build")

Arguments:

  • src_folder: (default ".") internally defines self.folders.source=src_folder if conanfile.folders.subproject is not defined, otherwise it will define the value relative to conanfile.folders.subproject
  • build_folder: (default "build") defines the base name for the folder containing the build artifacts.

Multi-setting/option cmake_layout

The folders.build and conanfile.folders.generators can be customized to take into account the settings and options and not only the build_type. Use the tools.cmake.cmake_layout:build_folder_vars conf to declare a list of settings or options:

conan install . -c tools.cmake.cmake_layout:build_folder_vars="['settings.compiler', 'options.shared']"

For the previous example, the values assigned by the cmake_layout (installing the Release/static default configuration) would be:

  • conanfile.folders.build:
    • build/apple-clang-shared_false: if the cmake generator is multi-configuration.
    • build/apple-clang-shared_false/Debug: if the cmake generator is single-configuration.
  • conanfile.folders.generators: build/generators

If we repeat the previous install with a different configuration:

conan install . -o shared=True -c tools.cmake.cmake_layout:build_folder_vars="['settings.compiler', 'options.shared']"

The values assigned by the cmake_layout (installing the Release/shared configuration) would be:

  • conanfile.folders.build:
    • build/apple-clang-shared_true: if the cmake generator is multi-configuration.
    • build/apple-clang-shared_true/Debug: if the cmake generator is single-configuration.
  • conanfile.folders.generators: build-apple-clang-shared_true/generators

So we can keep separated folders for any number of different configurations that we want to install.

The CMakePresets.json file generated at the CMakeToolchain generator, will also take this tools.cmake.cmake_layout:build_folder_vars config into account to generate different names for the presets, being very handy to install N configurations and building our project for any of them by selecting the chosen preset.

Note

The settings.build_type value is forbidden in tools.cmake.cmake_layout:build_folder_vars because the build_type is already managed automatically with multi-config support in CMakeDeps and CMakeToolchain.