CMake 3 Tools

Warning: These tools are being replaced by the Modern CMake. Some of the tools are still being maintained for now, but new projects should check that repository first.

A set of CMake modules to assist in building code, with some tools for common general use packages and a few High Energy Physics packages. These tools are built around modern CMake (See The Ultimate Guide to Modern CMake), which allows clean, simple user CMake files. Although modern CMake is still a little odd in a few places, it is relatively clean and descriptive.

Installing CMake 3 anywhere

CMake is incredibly easy to install. The following line will install the latest 3.7.2 on Linux to your .local directory:

wget -qO- "https://cmake.org/files/v3.7/cmake-3.7.2-Linux-x86_64.tar.gz" | tar --strip-components=1 -xz -C ~/.local

If you don't want to put this in the .local directory, simply replace with any pre-existing directory, and add <directory>/bin to your PATH. See the other files in CMake downloads to find similar installers for Mac and Windows, as well as the latest development versions.

AddGoogleTest

This is a downloader for GoogleTest, based on the excellent DownloadProject tool. Downloading a copy for each project is the recommended way to use GoogleTest (so much so, in fact, that they have disabled the automatic CMake install target), so this respects that design decision. This method downloads the project at configure time, so that IDE's correctly find the libraries. Using it is simple:

cmake_minimum_required(VERSION 3.4)
project(MyProject CXX)
list(APPEND CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake)

enable_testing() # Must be in main file

include(AddGoogleTest) # Could be in /tests/CMakeLists.txt
add_executable(SimpleTest SimpleTest.cu)
add_gtest(SimpleTest)

Note: add_gtest is just a macro that adds gtest, gmock, and gtest_main, and then runs add_test to create a test with the same name:

target_link_libraries(SimpleTest gtest gmock gtest_main)
add_test(SimpleTest SimpleTest)

FindROOT

The following is an example of a CMakeLists.txt file that will build a project using ROOT. Clone the repository to your project's cmake folder, or use git submodule add if you are already using git. The root-config tool should be in your PATH; if is not, please run source /my/root/install/bin/thisroot.sh to set your PATH and other useful variables. Then your CMakeLists.txt should look like:

cmake_minimum_required(VERSION 3.4)
project(MyProject CXX)
list(APPEND CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake)

find_package(ROOT 6 REQUIRED COMPONENTS Minuit)

add_executable(MyExecutable MySourceFile.cpp)
target_link_libraries(MyExecutable ROOT::ROOT ROOT::Minuit)

In most cases, you should specify the C++ version (ROOT sets the compiler and linker flags needed, so you can ignore it if using a ROOT target). In CMake < 3.8, that looks like this:

set(CMAKE_CXX_STANDARD 11)
set(CMAKE_CXX_EXTENSIONS OFF)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

If you are using CMake 3.8 (not yet released), you could replace the C++11 selection code with the following line right at the end:

target_compile_features(MyExecutable PUBLIC cxx_std_11)

AddHydra

See the example repository (under development) for an example of the CMake 3.8 AddHydra module.