ycm-build-system-support(7)¶

Contents

ycm-build-system-support(7)
- YCM Build System Support
- A Practical Example

YCM Build System Support ¶

YCM offers a few macros and Find scripts that can be used in your build system.

Generic Modules that add functionalities to CMake that might be useful in your project.

Find Package Modules, that help in finding software on the system.

Packaging Helper Modules, that are useful to simplify the generation of a package that can be used by other packages.

Support for new CMake features in older CMake versions.

Support for new features in CMake before these are actually released.

Support for 3rd party CMake modules.

Suppose you have created a package that contains a library, called TemplatePkg. You want to package this library, providing versioning, installation rules for header as well as binary files and cmake files for finding and using the library within other projects.

This is the code you need to add to your CMakeLists.txt:

cmake_minimum_required(VERSION 3.16)
project(TemplatePkg
        LANGUAGES CXX
        VERSION 0.0.1)

include(GNUInstallDirs)

# Set the output dir for binaries
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/${CMAKE_INSTALL_BINDIR})
set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/${CMAKE_INSTALL_LIBDIR})
set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/${CMAKE_INSTALL_LIBDIR})

# find and use YCM
find_package(YCM REQUIRED)

# Set a few
set(${PROJECT_NAME}_BUILD_LIBDIR ${CMAKE_INSTALL_LIBDIR})
set(${PROJECT_NAME}_BUILD_BINDIR ${CMAKE_INSTALL_BINDIR})
set(${PROJECT_NAME}_BUILD_INCLUDEDIR ${CMAKE_SOURCE_DIR}/src)

set(${PROJECT_NAME}_INSTALL_LIBDIR ${CMAKE_INSTALL_LIBDIR})
set(${PROJECT_NAME}_INSTALL_BINDIR ${CMAKE_INSTALL_BINDIR})
set(${PROJECT_NAME}_INSTALL_INCLUDEDIR ${CMAKE_INSTALL_INCLUDEDIR})

# add sources
add_subdirectory(src)

So far nothing special. We have declared our library, added source codes and included YCM.

We now need to instruct CMake to install the library and generate CMake (FindTemplatePkg.cmake) have also been generated so that TemplatePkg can be found using CMake.

# include macro for installing packaging files and invoke it
include(InstallBasicPackageFiles)
install_basic_package_files(TemplatePkg
                            VARS_PREFIX ${PROJECT_NAME}
                            VERSION ${${PROJECT_NAME}_VERSION}
                            COMPATIBILITY SameMajorVersion
                            NO_CHECK_REQUIRED_COMPONENTS_MACRO)

This function generates all the configuration files required for other packages to locate and use the library compiled by TemplatePkg and adds the required installation rules for these files.

Finally we add uninstall rules:

include(AddUninstallTarget)

Now you can compile the package by simply doing:

mkdir build
cd build
cmake ..
make
make install

This will install your package using /usr/local/ as installation prefix. You can change the prefix by changing the CMAKE_INSTALL_PREFIX variable, for example

cmake -DCMAKE_INSTALL_PREFIX:PATH=/opt/ycm ..

If you check inside the build directory or <prefix>/lib you should see that make install has built the project and installed header files and the library correctly. The file TemplatePkgConfig.cmake should be in <prefix>/lib/cmake/TemplatePkg/. This file will be found by other packages when they call:

find_package(TemplatePkg)

Example code can be downloaded from TemplatePkg repository.

ycm-build-system-support(7)¶