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_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 -DBUILD_TESTING=ON flag to run Abseil tests.

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 -DBUILD_TESTING=ON -DABSL_USE_GOOGLETEST_HEAD=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:

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

Traditional CMake Set-Up

For larger projects, it may make sense to use the traditional CMake set-up where you build and install projects separately.

First, you'd need to build and install Google Test:

cmake -S /source/googletest -B /build/googletest -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/installation/dir -DBUILD_GMOCK=ON
cmake --build /build/googletest --target install

Then you need to configure and build Abseil. Make sure you enable ABSL_USE_EXTERNAL_GOOGLETEST and ABSL_FIND_GOOGLETEST. You also need to enable ABSL_ENABLE_INSTALL so that you can install Abseil itself.

cmake -S /source/abseil-cpp -B /build/abseil-cpp -DCMAKE_PREFIX_PATH=/installation/dir -DCMAKE_INSTALL_PREFIX=/installation/dir -DABSL_ENABLE_INSTALL=ON -DABSL_USE_EXTERNAL_GOOGLETEST=ON -DABSL_FIND_GOOGLETEST=ON
cmake --build /temporary/build/abseil-cpp

(CMAKE_PREFIX_PATH is where you already have Google Test installed; CMAKE_INSTALL_PREFIX is where you want to have Abseil installed; they can be different.)

Run the tests:

ctest --test-dir /temporary/build/abseil-cpp

And finally install:

cmake --build /temporary/build/abseil-cpp --target install

CMake Option Synposis

Enable Standard CMake Installation

-DABSL_ENABLE_INSTALL=ON

Google Test Options

-DBUILD_TESTING=ON must be set to enable testing

Have Abseil download and build Google Test for you: -DABSL_USE_EXTERNAL_GOOGLETEST=OFF (default)
- Download and build latest Google Test: -DABSL_USE_GOOGLETEST_HEAD=ON
- Download specific Google Test version (ZIP archive): -DABSL_GOOGLETEST_DOWNLOAD_URL=https://.../version.zip
- Use Google Test from specific local directory: -DABSL_LOCAL_GOOGLETEST_DIR=/path/to/googletest
Use Google Test included elsewhere in your project: -DABSL_USE_EXTERNAL_GOOGLETEST=ON
Use standard CMake find_package(CTest) to find installed Google Test: -DABSL_USE_EXTERNAL_GOOGLETEST=ON -DABSL_FIND_GOOGLETEST=ON