Challenge Template

This is a basic setup to create some of my programming Challenges (and actually most of my other projects). It contains a CMakeLists.txt and conanfile.py as well as a basic Benchmark and Tests. It sets up and uses the following tools / libraries:

• CMake
• Conan
• GTest
• Google Microbenchmark

Note: By default this uses C++20 because I want to play around with the newest things.

What you have to change

Change the links on top for the badges, that should actually be about it :)

• Godbolt

Setup

Requirements:

• CMake
• Conan
• Python (for Conan)

Conan is tightly integrated into cmake and will be automatically called by it

mkdir build && cd build
cmake -G ...
cmake --build ..
ctest

Now you should see the library successfully compiling and running the tests.

Disabling some of the Dependencies

If you don't have the dependencies or dont want to build with them for some reason you can disable them with these CMake Options, simply set them to 'OFF'.

BUILD_REFERENCE
BUILD_TESTS
BUILD_BENCHMARK

Alternative without Conan

Requirements:

• CMake

You can build the library without Conan if you manually install the gtest and google benchmark libraries.

Just tell Cmake where to find them by setting following CMake Variables

gtest_DIR
benchmark_ROOT_DIR

Alternatively you can set the CMAKE_MODULE_PATH to the location where your Findgtest.cmake and Findbenchmark.cmake files are, if you have them.

Then you can use a command line like this

cmake .. -G "Unix Makefiles" -D CMAKE_C_COMPILER=gcc-9 -D CMAKE_CXX_COMPILER=g++-9 -DCMAKE_BUILD_TYPE=DEBUG -D CMAKE_MODULE_PATH=$PWD

For the Future

Some ideas that can be tried out...

• At the moment I use the Visual Studio open CMakeCache feature on windows, however I can not switch the config with the current setup. Maybe this can be improved (e.g. with cmake_find_package_multi generator).
• Experiment a little bit with CMake calling conan, as then there would be only one entry point. (Saw this somewhere before, there should be some helpers available online)

Issues discovered during Developement

While setting up this repository I came across several problems which I want to note down here.

Conan Generators dealing with Targets

Currently I'm using the 'cmake_find_package' generator which will create a 'findXXX.Cmake' file. This way I don't have to modify anything in the CMakeLists.txt compared to an approach without Conan. However since this file is automatically created it does not take into account all targets but creates only one for gtest for example.

Therefore I could not link against gtest::main but had to provide the main for myself. As the Gtest package comes with a Config.cmake I wonder if its possible to have the 'cmake_find_package' generator use that instead. But this is a separate story that should be adressed within Conan.

Ctest swallowing output

At first I wanted to show the benchmark output as part of the tests. However ctest by default swallows all the output and can only be brought to bring it up for failing tests, as far as I could see. I could not work my way around it and decided to make a target and not a test executing the benchmark.

Another separate Story would be adding an option to add_test in cmake to show the standard output.