CMakeLists: modify CMAKE_CXX_STANDARD

Author: KangLin

CMakeLists.txt

@@ -5,7 +5,7 @@ MESSAGE(STATUS "Found CMake ${CMAKE_VERSION}")
 
 project(SerialPortAssistant)
 
-set(CMAKE_CXX_STANDARD 17)
+#set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_VERBOSE_MAKEFILE ON CACHE BOOL "verbose")
 # Need qt components
@@ -61,6 +61,14 @@ message("Qt${QT_VERSION_MAJOR}_DIR:${Qt${QT_VERSION_MAJOR}_DIR}")
 message("QT_INSTALL_DIR:${QT_INSTALL_DIR}")
 message("QT_LIBRARIES:${QT_LIBRARIES}")
 
+if(QT_VERSION_MAJOR VERSION_GREATER_EQUAL 6)
+    set(CMAKE_CXX_STANDARD 17)
+    set(CMAKE_C_STANDARD 17)
+else()
+    set(CMAKE_CXX_STANDARD 11)
+    set(CMAKE_C_STANDARD 11)
+endif()
+
 message("CMAKE_PREFIX_PATH: ${CMAKE_PREFIX_PATH}")
 message("CMAKE_MODULE_PATH: ${CMAKE_MODULE_PATH}")
 message("CMAKE_FIND_USE_CMAKE_SYSTEM_PATH:${CMAKE_FIND_USE_CMAKE_SYSTEM_PATH}; NO_CMAKE_SYSTEM_PATH:${NO_CMAKE_SYSTEM_PATH}")