From 7e7f41e40c39361059ce4693c5e3a5e1ccd6f7e5 Mon Sep 17 00:00:00 2001 From: Simon Hausmann Date: Thu, 17 Oct 2019 10:14:09 +0200 Subject: [PATCH] Pick the latest available C/C++ standard when compiling Qt MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This maps the behavior of mkspecs/features/qt_common.prf and enables the use of C++17 for example in Android, where the toolchain supports it anyway. Change-Id: I41f4bdb160a3929e2fb78f36efb1ad5f2ad391a5 Reviewed-by: Qt CMake Build Bot Reviewed-by: Mårten Nordheim --- CMakeLists.txt | 2 ++ cmake/QtBuild.cmake | 19 +++++++++++++++++++ cmake/QtSetup.cmake | 7 ++----- 3 files changed, 23 insertions(+), 5 deletions(-) diff --git a/CMakeLists.txt b/CMakeLists.txt index 190a39a859b..98fe694adc8 100644 --- a/CMakeLists.txt +++ b/CMakeLists.txt @@ -35,6 +35,8 @@ include(QtBaseCMakeTesting) ## Targets for global features, etc.: include(QtBaseGlobalTargets) +qt_set_language_standards() + ## Should this Qt be static or dynamically linked? option(BUILD_SHARED_LIBS "Build Qt statically or dynamically" ON) set(QT_BUILD_SHARED_LIBS ${BUILD_SHARED_LIBS}) diff --git a/cmake/QtBuild.cmake b/cmake/QtBuild.cmake index 537979ad8a1..48d755450f9 100644 --- a/cmake/QtBuild.cmake +++ b/cmake/QtBuild.cmake @@ -3298,3 +3298,22 @@ function(qt_generate_qconfig_cpp) configure_file(global/qconfig.cpp.in global/qconfig.cpp @ONLY) endfunction() + +function(qt_set_language_standards) + ## Use the latest standard the compiler supports (same as qt_common.prf) + if (QT_FEATURE_cxx2a) + set(CMAKE_CXX_STANDARD 20 PARENT_SCOPE) + elseif (QT_FEATURE_cxx17) + set(CMAKE_CXX_STANDARD 17 PARENT_SCOPE) + elseif (QT_FEATURE_cxx14) + set(CMAKE_CXX_STANDARD 14 PARENT_SCOPE) + elseif (QT_FEATURE_cxx11) + set(CMAKE_CXX_STANDARD 11 PARENT_SCOPE) + endif() + + if (c_std_11 IN_LIST CMAKE_C_COMPILE_FEATURES) + set(CMAKE_C_STANDARD 11 PARENT_SCOPE) + elseif (c_std_99 IN_LIST CMAKE_C_COMPILE_FEATURES) + set(CMAKE_C_STANDARD 99 PARENT_SCOPE) + endif() +endfunction() diff --git a/cmake/QtSetup.cmake b/cmake/QtSetup.cmake index 16fd9b75205..6f42e337da5 100644 --- a/cmake/QtSetup.cmake +++ b/cmake/QtSetup.cmake @@ -24,11 +24,6 @@ elseif(APPLE) set(CMAKE_DEBUG_POSTFIX "_debug") endif() -## Force C++ standard, do not fall back, do not use compiler extensions -set(CMAKE_CXX_STANDARD 14) -set(CMAKE_CXX_STANDARD_REQUIRED ON) -set(CMAKE_CXX_EXTENSIONS OFF) - ## Position independent code: set(CMAKE_POSITION_INDEPENDENT_CODE ON) @@ -110,6 +105,8 @@ include(QtCompilerFlags) ## Set up non-prefix build: qt_set_up_nonprefix_build() +qt_set_language_standards() + ## Find host tools (if non native): set(QT_HOST_PATH "" CACHE PATH "Installed Qt host directory path, used for cross compiling.")