SciVision

CMake FetchContent is useful to incorporate subprojects at configure time. FetchContent subproject cache variables can override the top-level project cache, which can be confusing. A particular instance weve found problematic is overriding the CMake default install prefix. A top level project desiring to install to the CMake default location will g... et a surprising result if the child project overrides this. Instead, we recommend projects, including projects intended to be consumed via FetchContent use CMakePresets.json to set the default install directory: Meson subproject and CMake ExternalProject keep project namespaces separate. Meson subproject and CMake FetchContent download and configure all projects at configure time. CMake FetchContent comingles the CMake project namespaces. FetchContent can be easier to use than ExternalProject if you control both software projects' CMake scripts. If you dont control the child project, it may be better to use ExternalProject instead of FetchContent. For these examples, suppose we have a top-level project parent and a child project containing a library that is desired in parent. Suppose the child project can be built standalone (by itself) but also may be used directly from other CMake projects. FetchContent populates content from the other project at configure time. FetchContent populates the child project with default values from the parent project. Varibles set in the child project generally do not affect the parent project unless specifically used from the parent project. make child code configure, populating variables and targets as if it were part of parent CMake project. suppose child project CMakeLists.txt contains: The child project CMAKE_BINARY_DIR and CMAKE_SOURCE_DIR will be those of parent project. That is, if the parent project is in ~/foo and the build directory is ~/foo/build, then the child project in ~/childcode called by FetchContent will also have CMAKE_SOURCE_DIR of ~/foo and CMAKE_BINARY_DIR of ~/foo/build. So be careful in the child project when ...Read More