0032921: Configuration, CMake - allow selecting C++ standard.

Make C++ standard to be enable from cmake settings: User will be able choosing C++ language standard by selecting cmake variable BUILD_CPP_STANDARD. For correct working, CMAKE_CXX_STANDARD cmake built-in variable should be available. To enable CMAKE_CXX_STANDARD, minimum CMAKE version has been updated to 3.1. Available next standard items: C++11 C++14 C++17 C++20 C++23 This issue consists from several steps to achive main goal: 1) Configuratiuon, CMake - allow selecting C++ standard. 2) Require minimum CMAKE version 3.1 (for enabling CMAKE_CXX_STANDARD). 3) More flexible CMAKE_CXX_COMPILER_ID identification (fixups previous commit!) 4) Add description of new CMAKE variable `BUILD_CPP_STANDARD` into documentation. 5) Update CMAKE requirements in documentation. 6) Set C++11 standard for several projects.
2025-04-02 17:46:22 +03:00 · 2022-05-04 12:57:51 +03:00 · 2022-05-04 12:57:51 +03:00 · e92d322d40
commit e92d322d40
parent b71cb85f67
28 changed files with 143 additions and 50 deletions
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@ -1,4 +1,4 @@
-cmake_minimum_required (VERSION 2.8.12 FATAL_ERROR)
+cmake_minimum_required (VERSION 3.1 FATAL_ERROR)

 set (CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/adm/cmake")

@ -6,6 +6,26 @@ set (CMAKE_SUPPRESS_REGENERATION TRUE)

 set (CMAKE_CONFIGURATION_TYPES Release Debug RelWithDebInfo CACHE INTERNAL "" FORCE)

+# set using C++ standard
+set (BUILD_CPP_STANDARD "C++11" CACHE STRING "Select using c++ standard.")
+set_property(CACHE BUILD_CPP_STANDARD PROPERTY STRINGS "C++11" "C++14" "C++17" "C++20" "C++23")
+
+# Set desired C++ standard
+if     ("${BUILD_CPP_STANDARD}" STREQUAL "C++11")
+  set (CMAKE_CXX_STANDARD 11)
+elseif ("${BUILD_CPP_STANDARD}" STREQUAL "C++14")
+  set (CMAKE_CXX_STANDARD 14)
+elseif ("${BUILD_CPP_STANDARD}" STREQUAL "C++17")
+  set (CMAKE_CXX_STANDARD 17)
+elseif ("${BUILD_CPP_STANDARD}" STREQUAL "C++20")
+  set (CMAKE_CXX_STANDARD 20)
+elseif ("${BUILD_CPP_STANDARD}" STREQUAL "C++23")
+  set (CMAKE_CXX_STANDARD 23)
+else ()
+  message (FATAL_ERROR, "misprint in c++ standard name")
+endif()
+set (CMAKE_CXX_STANDARD_REQUIRED ON)
+
 # macro: include patched file if it exists
 macro (OCCT_INCLUDE_CMAKE_FILE BEING_INCLUDED_FILE)
  if (BUILD_PATCH AND EXISTS "${BUILD_PATCH}/${BEING_INCLUDED_FILE}.cmake")
--- a/adm/cmake/cotire.cmake
+++ b/adm/cmake/cotire.cmake
@ -32,15 +32,13 @@ if(__COTIRE_INCLUDED)
 endif()
 set(__COTIRE_INCLUDED TRUE)

-# call cmake_minimum_required, but prevent modification of the CMake policy stack in include mode
-# cmake_minimum_required also sets the policy version as a side effect, which we have to avoid
-if (NOT CMAKE_SCRIPT_MODE_FILE)
-	cmake_policy(PUSH)
-endif()
-cmake_minimum_required(VERSION 2.8.12)
-if (NOT CMAKE_SCRIPT_MODE_FILE)
-	cmake_policy(POP)
-endif()
+# Caution! Be careful, when increase minimal cmake version:
+# using of newer version may leads (by default) to applying
+# of some new policies. It may break compilation.
+# For canceling of applying new policies use:
+# cmake_policy(PUSH) before `cmake_minimum_required`
+# and cmake_policy(POP) after.
+cmake_minimum_required(VERSION 3.1 FATAL_ERROR)

 set (COTIRE_CMAKE_MODULE_FILE "${CMAKE_CURRENT_LIST_FILE}")
 set (COTIRE_CMAKE_MODULE_VERSION "1.7.9")
--- a/adm/cmake/occt_defs_flags.cmake
+++ b/adm/cmake/occt_defs_flags.cmake
@ -116,9 +116,9 @@ if (MSVC)
  else()
    set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /W4")
  endif()
-elseif (CMAKE_COMPILER_IS_GNUCC OR CMAKE_COMPILER_IS_GNUCXX OR "${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
+elseif (CMAKE_COMPILER_IS_GNUCC OR CMAKE_COMPILER_IS_GNUCXX OR (CMAKE_CXX_COMPILER_ID MATCHES "[Cc][Ll][Aa][Nn][Gg]"))
  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra")
-  if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
+  if (CMAKE_CXX_COMPILER_ID MATCHES "[Cc][Ll][Aa][Nn][Gg]")
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wshorten-64-to-32")
  endif()
  if (BUILD_SHARED_LIBS)
@ -130,14 +130,10 @@ elseif (CMAKE_COMPILER_IS_GNUCC OR CMAKE_COMPILER_IS_GNUCXX OR "${CMAKE_CXX_COMP
  endif()
 endif()

-if ("x${CMAKE_CXX_COMPILER_ID}" STREQUAL "xClang")
+if (CMAKE_CXX_COMPILER_ID MATCHES "[Cc][Ll][Aa][Nn][Gg]")
  if (APPLE)
    # CLang can be used with both libstdc++ and libc++, however on OS X libstdc++ is outdated.
-    set (CMAKE_CXX_FLAGS "-std=c++0x -stdlib=libc++ ${CMAKE_CXX_FLAGS}")
-  elseif(NOT WIN32)
-    # CLang for Windows (at least CLang 8.0 distributed with VS 2019)
-    # does not support option "-std=c++0x"
-    set (CMAKE_CXX_FLAGS "-std=c++0x ${CMAKE_CXX_FLAGS}")
+    set (CMAKE_CXX_FLAGS "-stdlib=libc++ ${CMAKE_CXX_FLAGS}")
  endif()
  # Optimize size of binaries
  set (CMAKE_SHARED_LINKER_FLAGS "-Wl,-s ${CMAKE_SHARED_LINKER_FLAGS}")
@ -148,14 +144,10 @@ elseif(MINGW)
  # workaround bugs in mingw with vtable export
  set (CMAKE_SHARED_LINKER_FLAGS "-Wl,--export-all-symbols")

-  # Require C++11
-  set (CMAKE_CXX_FLAGS "-std=gnu++0x ${CMAKE_CXX_FLAGS}")
  # Optimize size of binaries
  set (CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -s")
  set (CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} -s")
 elseif (DEFINED CMAKE_COMPILER_IS_GNUCXX)
-  # Require C++11
-  set (CMAKE_CXX_FLAGS "-std=c++0x ${CMAKE_CXX_FLAGS}")
  # Optimize size of binaries
  set (CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -s")
  set (CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} -s")
--- a/adm/cmake/occt_macros.cmake
+++ b/adm/cmake/occt_macros.cmake
@ -80,9 +80,9 @@ macro (OCCT_MAKE_COMPILER_SHORT_NAME)
    set (COMPILER gcc)
  elseif (DEFINED CMAKE_COMPILER_IS_GNUCXX)
    set (COMPILER gxx)
-  elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
+  elseif (CMAKE_CXX_COMPILER_ID MATCHES "[Cc][Ll][Aa][Nn][Gg]")
    set (COMPILER clang)
-  elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Intel")
+  elseif (CMAKE_CXX_COMPILER_ID MATCHES "[Ii][Nn][Tt][Ee][Ll]")
    set (COMPILER icc)
  else()
    set (COMPILER ${CMAKE_GENERATOR})
@ -589,9 +589,7 @@ macro (OCCT_UPDATE_TARGET_FILE)
  endif()

  install (CODE
-  "cmake_policy(PUSH)
-  cmake_policy(SET CMP0007 NEW)
-  string (TOLOWER \"\${CMAKE_INSTALL_CONFIG_NAME}\" CMAKE_INSTALL_CONFIG_NAME_LOWERCASE)
+  "string (TOLOWER \"\${CMAKE_INSTALL_CONFIG_NAME}\" CMAKE_INSTALL_CONFIG_NAME_LOWERCASE)
  file (GLOB ALL_OCCT_TARGET_FILES \"${INSTALL_DIR}/${INSTALL_DIR_CMAKE}/OpenCASCADE*Targets-\${CMAKE_INSTALL_CONFIG_NAME_LOWERCASE}.cmake\")
  foreach(TARGET_FILENAME \${ALL_OCCT_TARGET_FILES})
    file (STRINGS \"\${TARGET_FILENAME}\" TARGET_FILE_CONTENT)
@ -600,8 +598,7 @@ macro (OCCT_UPDATE_TARGET_FILE)
      string (REGEX REPLACE \"[\\\\]?[\\\$]{OCCT_INSTALL_BIN_LETTER}\" \"\${OCCT_INSTALL_BIN_LETTER}\" line \"\${line}\")
      file (APPEND \"\${TARGET_FILENAME}\" \"\${line}\\n\")
    endforeach()
-  endforeach()
-  cmake_policy(POP)")
+  endforeach()")
 endmacro()

 macro (OCCT_INSERT_CODE_FOR_TARGET)
@ -615,17 +612,14 @@ macro (OCCT_INSERT_CODE_FOR_TARGET)
 endmacro()

 macro (OCCT_UPDATE_DRAW_DEFAULT_FILE)
-  install(CODE "cmake_policy(PUSH)
-  cmake_policy(SET CMP0007 NEW)
-  set (DRAW_DEFAULT_FILE_NAME \"${INSTALL_DIR}/${INSTALL_DIR_RESOURCE}/DrawResources/DrawPlugin\")
+  install(CODE "set (DRAW_DEFAULT_FILE_NAME \"${INSTALL_DIR}/${INSTALL_DIR_RESOURCE}/DrawResources/DrawPlugin\")
  file (STRINGS \"\${DRAW_DEFAULT_FILE_NAME}\" DRAW_DEFAULT_CONTENT)
  file (REMOVE \"\${DRAW_DEFAULT_FILE_NAME}\")
  foreach (line IN LISTS DRAW_DEFAULT_CONTENT)
    string (REGEX MATCH \": TK\([a-zA-Z]+\)$\" IS_TK_LINE \"\${line}\")
    string (REGEX REPLACE \": TK\([a-zA-Z]+\)$\" \": TK\${CMAKE_MATCH_1}${BUILD_SHARED_LIBRARY_NAME_POSTFIX}\" line \"\${line}\")
    file (APPEND \"\${DRAW_DEFAULT_FILE_NAME}\" \"\${line}\\n\")
-  endforeach()
-  cmake_policy(POP)")
+  endforeach()")
 endmacro()

 macro (OCCT_CREATE_SYMLINK_TO_FILE LIBRARY_NAME LINK_NAME)
--- a/adm/cmake/occt_toolkit.cmake
+++ b/adm/cmake/occt_toolkit.cmake
@ -339,10 +339,10 @@ foreach (USED_ITEM ${USED_EXTERNLIB_AND_TOOLKITS})
      else() # get CSF_ value
        set (CURRENT_CSF ${${USED_ITEM}})
        if (NOT "x${CURRENT_CSF}" STREQUAL "x")
-          if ("${CURRENT_CSF}" STREQUAL "CSF_OpenGlLibs")
+          if ("${CURRENT_CSF}" STREQUAL "${CSF_OpenGlLibs}")
            add_definitions (-DHAVE_OPENGL)
          endif()
-          if ("${CURRENT_CSF}" STREQUAL "CSF_OpenGlesLibs")
+          if ("${CURRENT_CSF}" STREQUAL "${CSF_OpenGlesLibs}")
            add_definitions (-DHAVE_GLES2)
          endif()

--- a/dox/build/build_occt/building_occt.md
+++ b/dox/build/build_occt/building_occt.md
@ -17,7 +17,7 @@ On Linux and macOS we recommend to use libraries maintained by distributive deve
@section build_occt_win_cmake Building with CMake tool

 This chapter describes the [CMake](https://cmake.org/download/)-based build process, which is now suggested as a standard way to produce the binaries of Open CASCADE Technology from sources.
-OCCT requires CMake version 2.8.12 or later.
+OCCT requires CMake version 3.1 or later.

 CMake is a tool that generates the actual project files for the selected target build system (e.g. Unix makefiles) or IDE (e.g. Visual Studio 2010).
 Here we describe the build procedure on the example of Windows platform with Visual Studio 2010.
@ -113,6 +113,7 @@ The following table gives the full list of environment variables used at the con
 | BUILD_PATCH | Path | Points to the directory recognized as a "patch" for OCCT. If specified, the files from this directory take precedence over the corresponding native OCCT sources. This way you are able to introduce patches to Open CASCADE Technology not affecting the original source distribution |
 | BUILD_WITH_DEBUG | Boolean | Enables extended messages of many OCCT algorithms, usually printed to cout. These include messages on internal errors and special cases encountered, timing, etc. |
 | BUILD_ENABLE_FPE_SIGNAL_HANDLER | Boolean | Enable/Disable the floating point exceptions (FPE) during DRAW execution only. Corresponding environment variable (CSF_FPE) can be changed manually in custom.bat/sh scripts without regeneration by CMake. |
+| BUILD_CPP_STANDARD | String | Employ corresponding c++ standard (C++11, C++14, ..C++23) for building OCCT |
 | CMAKE_CONFIGURATION_TYPES | String | Semicolon-separated CMake configurations |
 | INSTALL_DIR          | Path | Points to the installation directory. *INSTALL_DIR* is a synonym of *CMAKE_INSTALL_PREFIX*. The user can specify both *INSTALL_DIR* or *CMAKE_INSTALL_PREFIX* |
 | INSTALL_DIR_BIN      | Path | Relative path to the binaries installation directory (absolute path is ${INSTALL_DIR}/${INSTALL_DIR_BIN}) |
--- a/dox/introduction/introduction.md
+++ b/dox/introduction/introduction.md
@ -359,7 +359,7 @@ https://dev.opencascade.org/resources/download/3rd-party-components

 | Component | Where to find | Used for | Purpose |
 | --------- | ------------- | -------- | -------------------- |
-| CMake 2.8+ | https://cmake.org/ | Configuration | Build from sources |
+| CMake 3.1+ | https://cmake.org/ | Configuration | Build from sources |
 | Intel TBB 4.x or later | https://oneapi-src.github.io/oneTBB/ | All | Parallelization of algorithms (alternative to built-in thread pool) |
 | OpenGL 3.3+, OpenGL ES 2.0+ | System | Visualization | Required for using 3D Viewer |
 | OpenVR 1.10+ | https://github.com/ValveSoftware/openvr | Visualization | VR (Virtual Reality) support in 3D Viewer |
--- a/samples/glfw/CMakeLists.txt
+++ b/samples/glfw/CMakeLists.txt
@ -4,7 +4,6 @@ project(glfw-occt-demo)

 set (CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/adm/cmake" ${CMAKE_MODULE_PATH})

-set(CMAKE_CXX_STANDARD 11)
 set(APP_VERSION_MAJOR 1)
 set(APP_VERSION_MINOR 0)
 set(APP_TARGET glfwocct)
--- a/samples/glfw/adm/cmake/FindOpenCASCADE.cmake
+++ b/samples/glfw/adm/cmake/FindOpenCASCADE.cmake
@ -39,9 +39,9 @@ elseif (DEFINED CMAKE_COMPILER_IS_GNUCC)
  set (MY_COMPILER gcc)
 elseif (DEFINED CMAKE_COMPILER_IS_GNUCXX)
  set (MY_COMPILER gcc)
-elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
+elseif (CMAKE_CXX_COMPILER_ID MATCHES "[Cc][Ll][Aa][Nn][Gg]")
  set (MY_COMPILER clang)
-elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Intel")
+elseif (CMAKE_CXX_COMPILER_ID MATCHES "[Ii][Nn][Tt][Ee][Ll]")
  set (MY_COMPILER icc)
 else()
  set (MY_COMPILER ${CMAKE_GENERATOR})
--- a/samples/java/jniviewer/app/src/main/jni/CMakeLists.txt
+++ b/samples/java/jniviewer/app/src/main/jni/CMakeLists.txt
@ -37,7 +37,7 @@ list(APPEND aLibDeps lib_FreeType)
 # system libraries
 list(APPEND aLibDeps EGL GLESv2 log android)

-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -Wall -frtti -fexceptions -fpermissive")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -frtti -fexceptions -fpermissive")

 add_library(TKJniSample SHARED ${SOURCE_FILES})
 target_link_libraries(TKJniSample ${aLibDeps})
--- a/samples/mfc/standard/01_Geometry/CMakeLists.txt
+++ b/samples/mfc/standard/01_Geometry/CMakeLists.txt
@ -1,4 +1,10 @@
-cmake_minimum_required (VERSION 2.6)
+# Caution! Be careful, when increase minimal cmake version:
+# using of newer version may leads (by default) to applying
+# of some new policies. It may break compilation.
+# For canceling of applying new policies use:
+# cmake_policy(PUSH) before `cmake_minimum_required`
+# and cmake_policy(POP) after.
+cmake_minimum_required (VERSION 3.1 FATAL_ERROR)

 project (Geometry)

--- a/samples/mfc/standard/02_Modeling/CMakeLists.txt
+++ b/samples/mfc/standard/02_Modeling/CMakeLists.txt
@ -1,4 +1,10 @@
-cmake_minimum_required (VERSION 2.6)
+# Caution! Be careful, when increase minimal cmake version:
+# using of newer version may leads (by default) to applying
+# of some new policies. It may break compilation.
+# For canceling of applying new policies use:
+# cmake_policy(PUSH) before `cmake_minimum_required`
+# and cmake_policy(POP) after.
+cmake_minimum_required (VERSION 3.1 FATAL_ERROR)

 project (Modeling)

--- a/samples/mfc/standard/03_ImportExport/CMakeLists.txt
+++ b/samples/mfc/standard/03_ImportExport/CMakeLists.txt
@ -1,4 +1,10 @@
-cmake_minimum_required (VERSION 2.6)
+# Caution! Be careful, when increase minimal cmake version:
+# using of newer version may leads (by default) to applying
+# of some new policies. It may break compilation.
+# For canceling of applying new policies use:
+# cmake_policy(PUSH) before `cmake_minimum_required`
+# and cmake_policy(POP) after.
+cmake_minimum_required (VERSION 3.1 FATAL_ERROR)

 project (ImportExport)

--- a/samples/mfc/standard/04_HLR/CMakeLists.txt
+++ b/samples/mfc/standard/04_HLR/CMakeLists.txt
@ -1,4 +1,10 @@
-cmake_minimum_required (VERSION 2.6)
+# Caution! Be careful, when increase minimal cmake version:
+# using of newer version may leads (by default) to applying
+# of some new policies. It may break compilation.
+# For canceling of applying new policies use:
+# cmake_policy(PUSH) before `cmake_minimum_required`
+# and cmake_policy(POP) after.
+cmake_minimum_required (VERSION 3.1 FATAL_ERROR)

 project (HLR)

--- a/samples/mfc/standard/mfcsample/CMakeLists.txt
+++ b/samples/mfc/standard/mfcsample/CMakeLists.txt
@ -1,4 +1,10 @@
-cmake_minimum_required (VERSION 2.6)
+# Caution! Be careful, when increase minimal cmake version:
+# using of newer version may leads (by default) to applying
+# of some new policies. It may break compilation.
+# For canceling of applying new policies use:
+# cmake_policy(PUSH) before `cmake_minimum_required`
+# and cmake_policy(POP) after.
+cmake_minimum_required (VERSION 3.1 FATAL_ERROR)

 project (mfcsample)

--- a/samples/webgl/CMakeLists.txt
+++ b/samples/webgl/CMakeLists.txt
@ -2,7 +2,6 @@ cmake_minimum_required(VERSION 3.2)

 project(occt-webgl-sample)

-set(CMAKE_CXX_STANDARD 11)
 set(APP_VERSION_MAJOR 1)
 set(APP_VERSION_MINOR 0)
 set(APP_TARGET occt-webgl-sample)
--- a/tools/CMakeLists.txt
+++ b/tools/CMakeLists.txt
@ -1,4 +1,10 @@
-cmake_minimum_required (VERSION 2.8.12 FATAL_ERROR)
+# Caution! Be careful, when increase minimal cmake version:
+# using of newer version may leads (by default) to applying
+# of some new policies. It may break compilation.
+# For canceling of applying new policies use:
+# cmake_policy(PUSH) before `cmake_minimum_required`
+# and cmake_policy(POP) after.
+cmake_minimum_required (VERSION 3.1 FATAL_ERROR)

 set (ADDITIONAL_INLCUDE_DIR_DESCR "Additional directory to be added in the projects include section")
 if (NOT DEFINED ADDITIONAL_INLCUDE_DIR)
--- a/tools/TInspectorEXE/CMakeLists.txt
+++ b/tools/TInspectorEXE/CMakeLists.txt
@ -5,3 +5,8 @@ set (EXECUTABLE_PROJECT ON)
 OCCT_INCLUDE_CMAKE_FILE (adm/cmake/occt_toolkit)
 unset (EXECUTABLE_PROJECT)
 OCCT_INCLUDE_CMAKE_FILE (adm/cmake/occt_toolkit_prepare_tool)
+
+# This project depends from Qt.
+# Qt 5.11.2 is incompatible with c++20.
+# So, it should be compiled with c++11/c++14 language standard.
+set_property(TARGET ${PROJECT_NAME} PROPERTY CXX_STANDARD 11)
--- a/tools/TKDFBrowser/CMakeLists.txt
+++ b/tools/TKDFBrowser/CMakeLists.txt
@ -3,3 +3,8 @@ project(TKDFBrowser)
 OCCT_INCLUDE_CMAKE_FILE (adm/cmake/occt_toolkit_prepare_tool)
 OCCT_INCLUDE_CMAKE_FILE (adm/cmake/occt_toolkit)
 OCCT_INCLUDE_CMAKE_FILE (adm/cmake/occt_toolkit_prepare_tool)
+
+# This project depends from Qt.
+# Qt 5.11.2 is incompatible with c++20.
+# So, it should be compiled with c++11/c++14 language standard.
+set_property(TARGET ${PROJECT_NAME} PROPERTY CXX_STANDARD 11)
--- a/tools/TKMessageModel/CMakeLists.txt
+++ b/tools/TKMessageModel/CMakeLists.txt
@ -3,3 +3,8 @@ project(TKMessageModel)
 OCCT_INCLUDE_CMAKE_FILE (adm/cmake/occt_toolkit_prepare_tool)
 OCCT_INCLUDE_CMAKE_FILE (adm/cmake/occt_toolkit)
 OCCT_INCLUDE_CMAKE_FILE (adm/cmake/occt_toolkit_prepare_tool)
+
+# This project depends from Qt.
+# Qt 5.11.2 is incompatible with c++20.
+# So, it should be compiled with c++11/c++14 language standard.
+set_property(TARGET ${PROJECT_NAME} PROPERTY CXX_STANDARD 11)
--- a/tools/TKMessageView/CMakeLists.txt
+++ b/tools/TKMessageView/CMakeLists.txt
@ -3,3 +3,8 @@ project(TKMessageView)
 OCCT_INCLUDE_CMAKE_FILE (adm/cmake/occt_toolkit_prepare_tool)
 OCCT_INCLUDE_CMAKE_FILE (adm/cmake/occt_toolkit)
 OCCT_INCLUDE_CMAKE_FILE (adm/cmake/occt_toolkit_prepare_tool)
+
+# This project depends from Qt.
+# Qt 5.11.2 is incompatible with c++20.
+# So, it should be compiled with c++11/c++14 language standard.
+set_property(TARGET ${PROJECT_NAME} PROPERTY CXX_STANDARD 11)
--- a/tools/TKShapeView/CMakeLists.txt
+++ b/tools/TKShapeView/CMakeLists.txt
@ -3,3 +3,8 @@ project(TKShapeView)
 OCCT_INCLUDE_CMAKE_FILE (adm/cmake/occt_toolkit_prepare_tool)
 OCCT_INCLUDE_CMAKE_FILE (adm/cmake/occt_toolkit)
 OCCT_INCLUDE_CMAKE_FILE (adm/cmake/occt_toolkit_prepare_tool)
+
+# This project depends from Qt.
+# Qt 5.11.2 is incompatible with c++20.
+# So, it should be compiled with c++11/c++14 language standard.
+set_property(TARGET ${PROJECT_NAME} PROPERTY CXX_STANDARD 11)
--- a/tools/TKTInspector/CMakeLists.txt
+++ b/tools/TKTInspector/CMakeLists.txt
@ -6,4 +6,9 @@ OCCT_INCLUDE_CMAKE_FILE (adm/cmake/occt_toolkit_prepare_tool)
 OCCT_INCLUDE_CMAKE_FILE (adm/cmake/occt_toolkit)
 OCCT_INCLUDE_CMAKE_FILE (adm/cmake/occt_toolkit_prepare_tool)

+# This project depends from Qt.
+# Qt 5.11.2 is incompatible with c++20.
+# So, it should be compiled with c++11/c++14 language standard.
+set_property(TARGET ${PROJECT_NAME} PROPERTY CXX_STANDARD 11)
+
 unset (INSTALL_API)
--- a/tools/TKTInspectorAPI/CMakeLists.txt
+++ b/tools/TKTInspectorAPI/CMakeLists.txt
@ -6,5 +6,9 @@ OCCT_INCLUDE_CMAKE_FILE (adm/cmake/occt_toolkit_prepare_tool)
 OCCT_INCLUDE_CMAKE_FILE (adm/cmake/occt_toolkit)
 OCCT_INCLUDE_CMAKE_FILE (adm/cmake/occt_toolkit_prepare_tool)

-UNSET (TOOL_API_LIBRARY)
+# This project depends from Qt.
+# Qt 5.11.2 is incompatible with c++20.
+# So, it should be compiled with c++11/c++14 language standard.
+set_property(TARGET ${PROJECT_NAME} PROPERTY CXX_STANDARD 11)

+UNSET (TOOL_API_LIBRARY)
--- a/tools/TKToolsDraw/CMakeLists.txt
+++ b/tools/TKToolsDraw/CMakeLists.txt
@ -3,3 +3,8 @@ project(TKToolsDraw)
 OCCT_INCLUDE_CMAKE_FILE (adm/cmake/occt_toolkit_prepare_tool)
 OCCT_INCLUDE_CMAKE_FILE (adm/cmake/occt_toolkit)
 OCCT_INCLUDE_CMAKE_FILE (adm/cmake/occt_toolkit_prepare_tool)
+
+# This project depends from Qt.
+# Qt 5.11.2 is incompatible with c++20.
+# So, it should be compiled with c++11/c++14 language standard.
+set_property(TARGET ${PROJECT_NAME} PROPERTY CXX_STANDARD 11)
--- a/tools/TKTreeModel/CMakeLists.txt
+++ b/tools/TKTreeModel/CMakeLists.txt
@ -3,3 +3,8 @@ project(TKTreeModel)
 OCCT_INCLUDE_CMAKE_FILE (adm/cmake/occt_toolkit_prepare_tool)
 OCCT_INCLUDE_CMAKE_FILE (adm/cmake/occt_toolkit)
 OCCT_INCLUDE_CMAKE_FILE (adm/cmake/occt_toolkit_prepare_tool)
+
+# This project depends from Qt.
+# Qt 5.11.2 is incompatible with c++20.
+# So, it should be compiled with c++11/c++14 language standard.
+set_property(TARGET ${PROJECT_NAME} PROPERTY CXX_STANDARD 11)
--- a/tools/TKVInspector/CMakeLists.txt
+++ b/tools/TKVInspector/CMakeLists.txt
@ -3,3 +3,8 @@ project(TKVInspector)
 OCCT_INCLUDE_CMAKE_FILE (adm/cmake/occt_toolkit_prepare_tool)
 OCCT_INCLUDE_CMAKE_FILE (adm/cmake/occt_toolkit)
 OCCT_INCLUDE_CMAKE_FILE (adm/cmake/occt_toolkit_prepare_tool)
+
+# This project depends from Qt.
+# Qt 5.11.2 is incompatible with c++20.
+# So, it should be compiled with c++11/c++14 language standard.
+set_property(TARGET ${PROJECT_NAME} PROPERTY CXX_STANDARD 11)
--- a/tools/TKView/CMakeLists.txt
+++ b/tools/TKView/CMakeLists.txt
@ -3,3 +3,8 @@ project(TKView)
 OCCT_INCLUDE_CMAKE_FILE (adm/cmake/occt_toolkit_prepare_tool)
 OCCT_INCLUDE_CMAKE_FILE (adm/cmake/occt_toolkit)
 OCCT_INCLUDE_CMAKE_FILE (adm/cmake/occt_toolkit_prepare_tool)
+
+# This project depends from Qt.
+# Qt 5.11.2 is incompatible with c++20.
+# So, it should be compiled with c++11/c++14 language standard.
+set_property(TARGET ${PROJECT_NAME} PROPERTY CXX_STANDARD 11)