Abseil CMake Build Instructions

Abseil comes with a CMake build script (CMakeLists.txt) that can be used on a wide range of platforms ("C" stands for cross-platform.). If you don't have CMake installed already, you can download it for free from https://www.cmake.org/.

CMake works by generating native makefiles or build projects that can be used in the compiler environment of your choice.

For API/ABI compatibility reasons, we strongly recommend building Abseil in a subdirectory of your project or as an embedded dependency.

Incorporating Abseil Into a CMake Project

The recommendations below are similar to those for using CMake within the googletest framework (https://github.com/google/googletest/blob/master/googletest/README.md#incorporating-into-an-existing-cmake-project)

Step-by-Step Instructions

If you want to build the Abseil tests, integrate the Abseil dependency Google Test into your CMake project. To disable Abseil tests, you have to pass -DBUILD_TESTING=OFF when configuring your project with CMake.
Download Abseil and copy it into a subdirectory in your CMake project or add Abseil as a git submodule in your CMake project.
You can then use the CMake command add_subdirectory() to include Abseil directly in your CMake project.
Add the absl:: target you wish to use to the target_link_libraries() section of your executable or of your library. Here is a short CMakeLists.txt example of a project file using Abseil.

```cmake cmake_minimum_required(VERSION 3.5) project(my_project)

Pick the C++ standard to compile with.

Abseil currently supports C++11, C++14, and C++17.

set(CMAKE_CXX_STANDARD 11)

add_subdirectory(abseil-cpp)

add_executable(my_exe source.cpp) target_link_libraries(my_exe absl::base absl::synchronization absl::strings) ```

Running Abseil Tests with CMake

Use the -DABSL_RUN_TESTS=ON flag to run Abseil tests. Note that if the -DBUILD_TESTING=OFF flag is passed then Abseil tests will not be run.

You will need to provide Abseil with a Googletest dependency. There are two options for how to do this:

Use -DABSL_USE_GOOGLETEST_HEAD. This will automatically download the latest Googletest source into the build directory at configure time. Googletest will then be compiled directly alongside Abseil's tests.
Manually integrate Googletest with your build. See https://github.com/google/googletest/blob/master/googletest/README.md#using-cmake for more information on using Googletest in a CMake project.

For example, to run just the Abseil tests, you could use this script:

cd path/to/abseil-cpp mkdir build cd build cmake -DABSL_USE_GOOGLETEST_HEAD=ON -DABSL_RUN_TESTS=ON .. make -j ctest

Currently, we only run our tests with CMake in a Linux environment, but we are working on the rest of our supported platforms. See https://github.com/abseil/abseil-cpp/projects/1 and https://github.com/abseil/abseil-cpp/issues/109 for more information.

Available Abseil CMake Public Targets

Here's a non-exhaustive list of Abseil CMake public targets:

cmake absl::algorithm absl::base absl::debugging absl::flat_hash_map absl::flags absl::memory absl::meta absl::numeric absl::random absl::strings absl::synchronization absl::time absl::utility