A lecture about installing and reusing packages with CMake (#109)

Author: niosus

lectures/cmake_install.md

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+cmake_minimum_required(VERSION 3.16..3.24)
+project(core_project
+ VERSION 0.0.1
+ DESCRIPTION "Sample project with a library target"
+ LANGUAGES CXX)
+
+if(NOT CMAKE_BUILD_TYPE)
+ set(CMAKE_BUILD_TYPE Release CACHE INTERNAL "Build type")
+endif()
+
+message(STATUS "CMAKE_BUILD_TYPE: ${CMAKE_BUILD_TYPE}")
+
+add_subdirectory(core_project)
+add_subdirectory(examples)
+
+include(CMakePackageConfigHelpers)
+
+# Create a config file that CMake looks for when we call FindPackage(core_project)
+configure_package_config_file(${CMAKE_CURRENT_SOURCE_DIR}/cmake/Config.cmake.in
+ "${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}Config.cmake"
+ INSTALL_DESTINATION "share/cmake/${PROJECT_NAME}"
+)
+
+# Create a versioned config file that CMake uses to compare version of the package.
+write_basic_package_version_file(
+ ${PROJECT_NAME}ConfigVersion.cmake
+ VERSION ${PACKAGE_VERSION}
+ COMPATIBILITY AnyNewerVersion
+)
+
+# Copy these files into the install directory.
+install(
+ FILES
+ ${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}Config.cmake
+ ${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}ConfigVersion.cmake
+ DESTINATION
+ share/cmake/${PROJECT_NAME}
+)

lectures/code/cmake_install/core_project/CMakeLists.txt

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+@PACKAGE_INIT@
+
+# Automatically include all exported library files
+file(GLOB EXPORT_FILES "${CMAKE_CURRENT_LIST_DIR}/*_export.cmake")
+foreach(EXPORT_FILE ${EXPORT_FILES})
+    include(${EXPORT_FILE})
+endforeach()
+
+check_required_components(core_project)

lectures/code/cmake_install/core_project/cmake/Config.cmake.in

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+set(LIBRARY_NAME some_library)
+add_library(${LIBRARY_NAME} ${LIBRARY_NAME}.cpp)
+target_compile_features(${LIBRARY_NAME} PUBLIC cxx_std_17)
+target_include_directories(${LIBRARY_NAME}
+    PUBLIC
+    $<BUILD_INTERFACE:${CMAKE_SOURCE_DIR}>
+    $<INSTALL_INTERFACE:include/>
+)
+add_library(${PROJECT_NAME}::${LIBRARY_NAME} ALIAS ${LIBRARY_NAME})
+
+install(
+    DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
+    DESTINATION include
+    FILES_MATCHING PATTERN "*.hpp"
+)
+
+install(
+    TARGETS ${LIBRARY_NAME}
+    EXPORT ${LIBRARY_NAME}_export
+)
+
+install(EXPORT ${LIBRARY_NAME}_export
+    FILE ${LIBRARY_NAME}_export.cmake
+    NAMESPACE ${PROJECT_NAME}::
+    DESTINATION share/cmake/${PROJECT_NAME}
+)

lectures/code/cmake_install/core_project/core_project/CMakeLists.txt

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+#include "core_project/some_library.hpp"
+
+#include <iostream>
+
+namespace core_project {
+
+void PrintHello() noexcept {
+    std::cout << "Hello world!" << std::endl;
+ }
+
+} // namespace core_project

lectures/code/cmake_install/core_project/core_project/some_library.cpp

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+#pragma once
+
+namespace core_project {
+
+void PrintHello() noexcept;
+
+} // namespace core_project

lectures/code/cmake_install/core_project/core_project/some_library.hpp

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+add_executable(print_hello print_hello.cpp)
+target_link_libraries(print_hello PRIVATE core_project::some_library)
+
+install(TARGETS print_hello)

lectures/code/cmake_install/core_project/examples/CMakeLists.txt

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+#include "core_project/some_library.hpp"
+
+int main() {
+  core_project::PrintHello();
+  return 0;
+}

lectures/code/cmake_install/core_project/examples/print_hello.cpp

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+cmake_minimum_required(VERSION 3.16..3.24)
+project(dependent_project
+    VERSION 0.0.1
+    DESCRIPTION "Sample project that uses the core project"
+    LANGUAGES CXX)
+
+add_subdirectory(examples)

lectures/code/cmake_install/dependent_project/CMakeLists.txt

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+find_package(core_project REQUIRED CONFIG)
+
+add_executable(print_hello print_hello.cpp)
+target_link_libraries(print_hello PRIVATE core_project::some_library)