abseil-cpp/CMake

Abseil CMake build instructions

Recommended usage : incorporate Abseil into an CMake project

For API / ABI compatibility reasons, it is recommended to build and use abseil in a subdirectory of your project or as an embedded dependency

This is similar to the recommended usage of the googletest framework ( https://github.com/google/googletest/blob/master/googletest/README.md )

Build and use step-by-step

1- Download abseil and copy it in a sub-directory in your project. or add abseil as a git-submodule in your project

2- If not done yet, download and copy in your project the two dependencies of abseil cctz and googletest

* cctz  https://github.com/google/cctz
* googletest https://github.com/google/googletest

3- You can then use the cmake command add_subdirectory() to include abseil directly and use the abseil targets in your project.

Note: Abseil requires CCTZ and the googletest framework. Consequently,
the targets  `gtest`, `gtest_main`, `gmock` and `cctz` need
to be declared in your project before including abseil with
`add_subdirectory`. However, if abseil is compiled with
`-DBUILD_TESTING=OFF`, then `gtest`, `gmock` and `gtest_main` are not
required. In addition, it's possible to override the name of the `cctz`
target to a custom one with option `-DABSL_CCTZ_TARGET=*my_cctz*`.

4- 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 possible project file
  using abseil

  cmake_minimum_required(VERSION 2.8.12)
  project(my_project)

  set(CMAKE_CXX_FLAGS "-std=c++11 -stdlib=libc++ ${CMAKE_CXX_FLAGS}")

  if (MSVC)
    # /wd4005  macro-redefinition
    # /wd4068  unknown pragma
    # /wd4244  conversion from 'type1' to 'type2'
    # /wd4267  conversion from 'size_t' to 'type2'
    # /wd4800  force value to bool 'true' or 'false' (performance warning)
    add_compile_options(/wd4005 /wd4068 /wd4244 /wd4267 /wd4800)
    add_definitions(/DNOMINMAX /DWIN32_LEAN_AND_MEAN=1 /D_CRT_SECURE_NO_WARNINGS)
  endif()

  add_subdirectory(googletest)
  add_subdirectory(cctz)
  add_subdirectory(abseil-cpp)

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

As of this writing, that pull request requires -DBUILD_TESTING=OFF as it doesn't correctly export cctz's dependency on Google Benchmark.

You will find here a non exhaustive list of absl public targets

  absl::base
  absl::algorithm
  absl::container
  absl::debugging
  absl::memory
  absl::meta
  absl::numeric
  absl::strings
  absl::synchronization
  absl::time
  absl::utility