Make USE_LATEST_STD cmake option.-

Determine minimum cxx standard for library.
rttrorg · Jan 27, 2019 · d4f31cd · d4f31cd
1 parent d5e15bc
commit d4f31cd
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Showing 3 changed files with 26 additions and 7 deletions.
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -60,6 +60,7 @@ option(BUILD_PACKAGE "Enable this to build the installer" ON)
 option(USE_PCH "Use precompiled header files for compilation" ON)
 option(CUSTOM_DOXYGEN_STYLE "Enable this option to use a custom doxygen style for HTML documentation; Otherwise the default will be used" ON)
 option(BUILD_WEBSITE_DOCU "Enable this option to create the special docu for the website" OFF)
+option(USE_LATEST_STD "Build the library using the latest std-library fetures and making it probably not backward compatible." OFF)
 
 # one precompiled headers cannot be used for multiple ninja targets
 # thats why we have to disable this option, when BUILD_STATIC or

diff --git a/src/rttr/CMakeLists.txt b/src/rttr/CMakeLists.txt
@@ -39,28 +39,38 @@ if (USE_PCH)
     activate_precompiled_headers("detail/base/pch.h" SRC_FILES)
 endif()
 
+# Determine the minium required standard.
+if (USE_LATEST_STD)
+    if (MAX_CXX_STANDARD GREATER_EQUAL 17)
+        list(APPEND COMPILE_DEFS "RTTR_USE_STD_STRING_VIEW")
+        set(MIN_CXX_STANDARD cxx_std_17)
+    endif ()
+else ()
+    set(MIN_CXX_STANDARD cxx_std_11) # at least c++11 is needed to compile RTTR
+endif ()
+
 if (${BUILD_RTTR_DYNAMIC})
     add_library(rttr_core SHARED ${UnityBuild} ${SRC_FILES} ${HPP_FILES})
     add_library(RTTR::Core ALIAS rttr_core)
 
     target_compile_definitions(rttr_core PRIVATE RTTR_DLL_EXPORTS)
     target_compile_definitions(rttr_core PUBLIC RTTR_DLL)
 
-
-
     set_target_properties(rttr_core PROPERTIES
                           VERSION ${RTTR_VERSION} SOVERSION ${RTTR_VERSION}
                           EXPORT_NAME Core
                           DEBUG_POSTFIX ${RTTR_DEBUG_POSTFIX}
                           CXX_STANDARD ${MAX_CXX_STANDARD}
                           CXX_VISIBILITY_PRESET hidden
                           VISIBILITY_INLINES_HIDDEN 1)
-
+
+    target_compile_definitions(rttr_core PUBLIC ${COMPILE_DEFS})
+
     target_link_libraries(rttr_core PRIVATE ${CMAKE_DL_LIBS})
 
 
     if(${CMAKE_VERSION} VERSION_GREATER "3.8.0") 
-        target_compile_features(rttr_core PUBLIC cxx_std_11) # at least c++11 is needed to compile RTTR
+        target_compile_features(rttr_core PUBLIC ${MIN_CXX_STANDARD}) 
     endif()
 
     target_include_directories(rttr_core PUBLIC
@@ -94,7 +104,9 @@ if (BUILD_STATIC)
                           EXPORT_NAME Core_Lib
                           CXX_STANDARD ${MAX_CXX_STANDARD}
                           DEBUG_POSTFIX ${RTTR_DEBUG_POSTFIX})
-
+
+    target_compile_definitions(rttr_core PUBLIC ${COMPILE_DEFS})
+
     target_link_libraries(rttr_core_lib PRIVATE ${CMAKE_DL_LIBS})
 
     if (MSVC)
@@ -139,6 +151,8 @@ if (BUILD_WITH_STATIC_RUNTIME_LIBS)
                                $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/../>
                                $<INSTALL_INTERFACE:include>)
 
+    target_compile_definitions(rttr_core PUBLIC ${COMPILE_DEFS})
+
     target_link_libraries(rttr_core_s PRIVATE ${CMAKE_DL_LIBS})
 
     set_target_properties(rttr_core_s PROPERTIES

diff --git a/src/rttr/detail/base/core_prerequisites.h b/src/rttr/detail/base/core_prerequisites.h
@@ -353,8 +353,12 @@ namespace rttr
 /////////////////////////////////////////////////////////////////////////////////////////
 // Enable some C++17 Features
 /////////////////////////////////////////////////////////////////////////////////////////
-#if __cplusplus >= 201703L
-    #define RTTR_ENABLE_STD_STRING_VIEW
+#ifdef RTTR_USE_STD_STRING_VIEW
+    #if __cplusplus >= 201703L
+        #define RTTR_ENABLE_STD_STRING_VIEW
+    #else
+        #error "Linking with this library needs C++17, as std::string_view is required."
+    #endif
 #endif
 
 } // end namespace rttr