-
Notifications
You must be signed in to change notification settings - Fork 362
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
- Loading branch information
ConanCI bot
committed
Feb 23, 2024
1 parent
9d2a72e
commit 9aacaa8
Showing
565 changed files
with
2,253 additions
and
565 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
140 changes: 140 additions & 0 deletions
140
2.1/_sources/examples/tools/cmake/cmake_toolchain/use_package_config_cmake.rst.txt
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,140 @@ | ||
| .. _examples-tools-cmake-toolchain-use-package-config-cmake: | ||
|
|
||
| CMakeToolchain: Using xxx-config.cmake files inside packages | ||
| ============================================================ | ||
|
|
||
| Conan relies in the general case in the ``package_info()`` abstraction to allow packages built with any build system | ||
| to be usable from any other package built with any other build system. In the CMake case, Conan relies on the | ||
| ``CMakeDeps`` generator to generate ``xxxx-config.cmake`` files for every dependency, even if those dependencies | ||
| didn't generate one or aren't built with CMake at all. | ||
|
|
||
| ConanCenter users this abstraction, not packaging the ``xxx-config.cmake`` files, and using the information in ``package_info()``. | ||
| This is very important to provide as build-system agnostic as possible packages and be fair with different build systems, | ||
| vendors and users. For example, there are many Conan users happily using native MSBuild (VS) projects without any CMake at all. | ||
| If ConanCenter packages were only built using the in-package ``config.cmake`` files, this wouldn't be possible. | ||
|
|
||
| But the fact that ConanCenter does that, doesn't mean that this is not possible or mandatory. It is perfectly possible | ||
| to use the in-packages ``xxx-config.cmake`` files, dropping the usage of ``CMakeDeps`` generator. | ||
|
|
||
|
|
||
| You can find the sources to recreate this example in the `examples2 repository | ||
| <https://github.com/conan-io/examples2>`_ in GitHub: | ||
|
|
||
| .. code-block:: bash | ||
| $ git clone https://github.com/conan-io/examples2.git | ||
| $ cd examples2/examples/tools/cmake/pkg_config_files | ||
| If we have a look to the ``conanfile.py``: | ||
|
|
||
| .. code-block:: python | ||
| class pkgRecipe(ConanFile): | ||
| name = "pkg" | ||
| version = "0.1" | ||
| ... | ||
| def package_info(self): | ||
| # No information provided, only the in-package .cmake is used here | ||
| # Other build systems or CMake via CMakeDeps will fail | ||
| self.cpp_info.builddirs = ["pkg/cmake"] | ||
| self.cpp_info.set_property("cmake_find_mode", "none") | ||
| This is a very typical recipe, the main difference is the ``package_info()`` method. Three important things to notice: | ||
|
|
||
| - It doesn't define fields like ``self.cpp_info.libs = ["mypkg"]``. Conan will not be propagating this information to | ||
| the consumer, the only place this information will be is inside the in-package ``xxx-config.cmake`` file | ||
| - Just in case there are some users still instantiating ``CMakeDeps``, it is disabling the client side generation of the | ||
| ``xxx-config.cmake`` file with ``set_property("cmake_find_mode", "none")`` | ||
| - It is defining that it will contain the build scripts (like the ``xxx-config.cmake`` package) inside that folder, to | ||
| be located by consumers. | ||
|
|
||
| So the responsibility of defining the package details has been transferred to the ``CMakeLists.txt`` that contains: | ||
|
|
||
| .. code-block:: cmake | ||
| add_library(mylib src/pkg.cpp) # Use a different name than the package, to make sure | ||
| set_target_properties(mylib PROPERTIES PUBLIC_HEADER "include/pkg.h") | ||
| target_include_directories(mylib PUBLIC | ||
| $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include> | ||
| $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}> | ||
| ) | ||
| # Use non default mypkgConfig name | ||
| install(TARGETS mylib EXPORT mypkgConfig) | ||
| export(TARGETS mylib | ||
| NAMESPACE mypkg:: # to simulate a different name and see it works | ||
| FILE "${CMAKE_CURRENT_BINARY_DIR}/mypkgConfig.cmake" | ||
| ) | ||
| install(EXPORT mypkgConfig | ||
| DESTINATION "${CMAKE_INSTALL_PREFIX}/pkg/cmake" | ||
| NAMESPACE mypkg:: | ||
| ) | ||
| With that information, when ``conan create`` is executed: | ||
|
|
||
| - The ``build()`` method will build the package | ||
| - The ``package()`` method will call ``cmake install``, which will create the ``mypkgConfig.cmake`` file | ||
| - It will be created in the package folder ``pkg/cmake/mypkgConfig.cmake`` file | ||
| - It will contain enough information for the headers, and it will create a ``mypkg::mylib`` target. | ||
|
|
||
| Note that the details of the config filename, the namespace and the target are also not known by Conan, | ||
| so this is also something that the consumer build scripts should know. | ||
|
|
||
|
|
||
| This is enough to have a package with an internal ``mypkgConfig.cmake`` file that can be used by consumers. | ||
| In this example code, the consumer is just the ``test_package/conanfile.py``, but exactly the same wouldn | ||
| apply to any arbitrary consumer. | ||
|
|
||
| The consumer ``conanfile.py`` doesn't need to use ``CMakeDeps`` at all, only ``generators = "CMakeToolchain"``. | ||
| Note that the ``CMakeToolchain`` generator is still necessary, because the ``mypkgConfig.cmake`` needs to | ||
| be found inside the Conan cache. The ``CMakeToolchain`` generated ``conan_toolchain.cmake`` file contains | ||
| these paths defined. | ||
|
|
||
| The consumer ``CMakeLists.txt`` would be standard: | ||
|
|
||
| .. code-block:: cmake | ||
| find_package(mypkg CONFIG REQUIRED) | ||
| add_executable(example src/example.cpp) | ||
| target_link_libraries(example mypkg::mylib) | ||
| You can verify it works with: | ||
|
|
||
| .. code-block:: bash | ||
| $ conan create . | ||
| ======== Testing the package: Executing test ======== | ||
| pkg/0.1 (test package): Running test() | ||
| pkg/0.1 (test package): RUN: Release\example | ||
| pkg/0.1: Hello World Release! | ||
| pkg/0.1: _M_X64 defined | ||
| pkg/0.1: MSVC runtime: MultiThreadedDLL | ||
| pkg/0.1: _MSC_VER1939 | ||
| pkg/0.1: _MSVC_LANG201402 | ||
| pkg/0.1: __cplusplus199711 | ||
| pkg/0.1 test_package | ||
| Important considerations | ||
| ------------------------ | ||
|
|
||
| The presented approach has one limitation, it doesn't work for multi-configuration IDEs. | ||
| Implementing this approach won't allow developers to directly switch from IDEs like Visual Studio from Release to Debug | ||
| and viceversa, and it will require a ``conan install`` to change. It is not an issue at all for single-config setups, | ||
| but for VS developers it can be a bit inconvenient. The team is working on the VS plugin that might help to mitigate this. | ||
| The reason is a CMake limitation, ``find_package()`` can only find one configuration, and with ``CMakeDeps`` being dropped | ||
| here, there is nothing that Conan can do to avoid this limitation. | ||
|
|
||
| It is important to know that it is also the package author and the package ``CMakeLists.txt`` responsibility to correctly | ||
| manage transitivity to other dependencies, and this is not trivial in some cases. There are risks that if not done | ||
| correctly the in-package ``xxx-config.cmake`` file can locate its transitive dependencies elsewhere, like in the system, | ||
| but not in the transtive Conan package dependencies. | ||
|
|
||
| Finally, recall that these packages won't be usable by other build systems rather than CMake. |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Binary file not shown.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Oops, something went wrong.