diff --git a/CMakeLists.txt b/CMakeLists.txt index d0515b96c..90a14a170 100755 --- a/CMakeLists.txt +++ b/CMakeLists.txt @@ -85,11 +85,26 @@ else() endif() endif() -# Check that root is compiled with a modern enough c++ standard -get_target_property(ROOT_COMPILE_FEATURES ROOT::Core INTERFACE_COMPILE_FEATURES) -if (NOT "cxx_std_17" IN_LIST ROOT_COMPILE_FEATURES AND NOT "cxx_std_20" IN_LIST ROOT_COMPILE_FEATURES) +# ROOT_CXX_STANDARD was introduced in https://github.com/root-project/root/pull/6466 +# before that it's an empty variable so we check if it's any number > 0 +if(NOT DEFINED ROOT_CXX_STANDARD) + get_target_property(ROOT_COMPILE_FEATURES ROOT::Core INTERFACE_COMPILE_FEATURES) + if("cxx_std_17" IN_LIST ROOT_COMPILE_FEATURES) + set(ROOT_CXX_STANDARD 17) + elseif("cxx_std_20" IN_LIST ROOT_COMPILE_FEATURES) + set(ROOT_CXX_STANDARD 20) + else() + message(FATAL_ERROR "ROOT C++ could not be detected") + endif() +endif() + +if(ROOT_CXX_STANDARD VERSION_LESS 17) message(FATAL_ERROR "You are trying to build podio against a version of ROOT that has not been built with a sufficient c++ standard. podio requires c++17 or higher") endif() +if(NOT ROOT_CXX_STANDARD VERSION_EQUAL CMAKE_CXX_STANDARD) + message(WARNING "You are trying to build podio with a different c++ standard than ROOT. C++${CMAKE_CXX_STANDARD} was required but ROOT was built with C++${ROOT_CXX_STANDARD}") +endif() + #Check if Python version detected matches the version used to build ROOT SET(Python_FIND_FRAMEWORK LAST) IF((TARGET ROOT::PyROOT OR TARGET ROOT::ROOTTPython) AND ${ROOT_VERSION} VERSION_GREATER_EQUAL 6.19)