From 6f6886156d986d83e33f97578bd3eb66b36fb40a Mon Sep 17 00:00:00 2001 From: Evan Cox Date: Thu, 11 Aug 2022 14:55:04 -0400 Subject: add new CMake option `ABSL_USE_SYSTEM_INCLUDES` When using Abseil as a dependency with CMake, files that include Abseil headers and have incompatible warning settings can emit compiler warnings. CMake allows you to mark include directories as `SYSTEM` includes, which causes compilers to ignore warnings from those headers. This adds the new option `ABSL_USE_SYSTEM_INCLUDES`, which makes Abseil's include directories be marked with `SYSTEM`. --- CMake/AbseilHelpers.cmake | 10 ++++++++-- CMakeLists.txt | 4 ++++ 2 files changed, 12 insertions(+), 2 deletions(-) diff --git a/CMake/AbseilHelpers.cmake b/CMake/AbseilHelpers.cmake index f81d57cf..96d815dd 100644 --- a/CMake/AbseilHelpers.cmake +++ b/CMake/AbseilHelpers.cmake @@ -26,6 +26,12 @@ if(NOT DEFINED ABSL_IDE_FOLDER) set(ABSL_IDE_FOLDER Abseil) endif() +if(ABSL_USE_SYSTEM_INCLUDES) + set(ABSL_INTERNAL_INCLUDE_WARNING_GUARD SYSTEM) +else() + set(ABSL_INTERNAL_INCLUDE_WARNING_GUARD "") +endif() + # absl_cc_library() # # CMake function to imitate Bazel's cc_library rule. @@ -242,7 +248,7 @@ Cflags: -I\${includedir}${PC_CFLAGS}\n") # unconditionally. set_property(TARGET ${_NAME} PROPERTY LINKER_LANGUAGE "CXX") - target_include_directories(${_NAME} + target_include_directories(${_NAME} ${ABSL_INTERNAL_INCLUDE_WARNING_GUARD} PUBLIC "$" $ @@ -290,7 +296,7 @@ Cflags: -I\${includedir}${PC_CFLAGS}\n") else() # Generating header-only library add_library(${_NAME} INTERFACE) - target_include_directories(${_NAME} + target_include_directories(${_NAME} ${ABSL_INTERNAL_INCLUDE_WARNING_GUARD} INTERFACE "$" $ diff --git a/CMakeLists.txt b/CMakeLists.txt index 10acf3b7..6f96c28e 100644 --- a/CMakeLists.txt +++ b/CMakeLists.txt @@ -70,6 +70,10 @@ if((${CMAKE_VERSION} VERSION_GREATER_EQUAL 3.8) AND (NOT ABSL_PROPAGATE_CXX_STD) message(WARNING "A future Abseil release will default ABSL_PROPAGATE_CXX_STD to ON for CMake 3.8 and up. We recommend enabling this option to ensure your project still builds correctly.") endif() +option(ABSL_USE_SYSTEM_INCLUDES + "Mark C++ include directories with `SYSTEM` to prevent warnings from headers when using Abseil with incompatible warning flags" + OFF) + list(APPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_LIST_DIR}/CMake ${CMAKE_CURRENT_LIST_DIR}/absl/copts -- cgit v1.2.3