fc8dc48020
git-subtree-dir: third_party/abseil_cpp git-subtree-mainline:ffb2ae54begit-subtree-split:768eb2ca28
101 lines
3.4 KiB
Markdown
101 lines
3.4 KiB
Markdown
# Abseil CMake Build Instructions
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Abseil comes with a CMake build script ([CMakeLists.txt](../CMakeLists.txt))
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that can be used on a wide range of platforms ("C" stands for cross-platform.).
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If you don't have CMake installed already, you can download it for free from
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<https://www.cmake.org/>.
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CMake works by generating native makefiles or build projects that can
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be used in the compiler environment of your choice.
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For API/ABI compatibility reasons, we strongly recommend building Abseil in a
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subdirectory of your project or as an embedded dependency.
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## Incorporating Abseil Into a CMake Project
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The recommendations below are similar to those for using CMake within the
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googletest framework
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(<https://github.com/google/googletest/blob/master/googletest/README.md#incorporating-into-an-existing-cmake-project>)
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### Step-by-Step Instructions
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1. If you want to build the Abseil tests, integrate the Abseil dependency
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[Google Test](https://github.com/google/googletest) into your CMake project. To disable Abseil tests, you have to pass
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`-DBUILD_TESTING=OFF` when configuring your project with CMake.
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2. Download Abseil and copy it into a subdirectory in your CMake project or add
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Abseil as a [git submodule](https://git-scm.com/docs/git-submodule) in your
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CMake project.
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3. You can then use the CMake command
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[`add_subdirectory()`](https://cmake.org/cmake/help/latest/command/add_subdirectory.html)
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to include Abseil directly in your CMake project.
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4. Add the **absl::** target you wish to use to the
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[`target_link_libraries()`](https://cmake.org/cmake/help/latest/command/target_link_libraries.html)
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section of your executable or of your library.<br>
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Here is a short CMakeLists.txt example of a project file using Abseil.
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```cmake
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cmake_minimum_required(VERSION 3.5)
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project(my_project)
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# Pick the C++ standard to compile with.
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# Abseil currently supports C++11, C++14, and C++17.
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set(CMAKE_CXX_STANDARD 11)
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add_subdirectory(abseil-cpp)
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add_executable(my_exe source.cpp)
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target_link_libraries(my_exe absl::base absl::synchronization absl::strings)
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```
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### Running Abseil Tests with CMake
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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.
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You will need to provide Abseil with a Googletest dependency. There are two
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options for how to do this:
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* Use `-DABSL_USE_GOOGLETEST_HEAD`. This will automatically download the latest
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Googletest source into the build directory at configure time. Googletest will
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then be compiled directly alongside Abseil's tests.
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* Manually integrate Googletest with your build. See
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https://github.com/google/googletest/blob/master/googletest/README.md#using-cmake
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for more information on using Googletest in a CMake project.
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For example, to run just the Abseil tests, you could use this script:
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```
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cd path/to/abseil-cpp
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mkdir build
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cd build
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cmake -DABSL_USE_GOOGLETEST_HEAD=ON -DABSL_RUN_TESTS=ON ..
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make -j
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ctest
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```
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Currently, we only run our tests with CMake in a Linux environment, but we are
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working on the rest of our supported platforms. See
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https://github.com/abseil/abseil-cpp/projects/1 and
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https://github.com/abseil/abseil-cpp/issues/109 for more information.
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### Available Abseil CMake Public Targets
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Here's a non-exhaustive list of Abseil CMake public targets:
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```cmake
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absl::algorithm
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absl::base
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absl::debugging
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absl::flat_hash_map
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absl::flags
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absl::memory
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absl::meta
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absl::numeric
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absl::random_random
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absl::strings
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absl::synchronization
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absl::time
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absl::utility
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```
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