Fix the c++ version configuration in cmake

Author: Robert-Andrzejuk-Infor

CMakeLists.txt

@@ -2,7 +2,20 @@
 
 cmake_minimum_required(VERSION 3.25)
 
-project(beman.scope DESCRIPTION "Generic Scope Guard" LANGUAGES CXX
+project(beman.scope DESCRIPTION "Generic Scope Guard" LANGUAGES CXX)
+
+# Define an option for the C++ standard with a default of 20
+option(CXX_STANDARD "C++ standard to use (minimum C++20)" 20)
+
+# Ensure the specified standard is at least C++20
+if (CXX_STANDARD LESS 20)
+    message(FATAL_ERROR "The minimum required C++ standard is C++20")
+endif()
+
+# Set the C++ standard based on the user input
+set(CMAKE_CXX_STANDARD ${CXX_STANDARD})
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_CXX_EXTENSIONS OFF)
 
 enable_testing()
 

CMakePresets.json

@@ -7,7 +7,7 @@
       "generator": "Ninja",
       "binaryDir": "${sourceDir}/build/${presetName}",
       "cacheVariables": {
-        "CMAKE_CXX_STANDARD": "20"
+        "CXX_STANDARD": "20"
       }
     },
     {

examples/CMakeLists.txt

@@ -1,9 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
-set(CMAKE_CXX_STANDARD 20)            # Set the C++ standard to C++20
-set(CMAKE_CXX_STANDARD_REQUIRED ON)   # Ensure the standard is required
-set(CMAKE_CXX_EXTENSIONS OFF)         # Disable compiler-specific extensions
-
 set(ALL_EXAMPLES scope_example)
 
 message("Examples to be built: ${ALL_EXAMPLES}")
@@ -13,3 +9,4 @@ foreach(example ${ALL_EXAMPLES})
     target_sources(beman.scope.examples.${example} PRIVATE ${example}.cpp)
     target_link_libraries(beman.scope.examples.${example} beman::scope)
 endforeach()
+

tests/beman/scope/CMakeLists.txt

@@ -1,12 +1,10 @@
 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
-set(CMAKE_CXX_STANDARD 20)            # Set the C++ standard to C++20
-set(CMAKE_CXX_STANDARD_REQUIRED ON)   # Ensure the standard is required
-set(CMAKE_CXX_EXTENSIONS OFF)         # Disable compiler-specific extensions
 
 add_executable(beman.scope.tests.scope)
 target_sources(beman.scope.tests.scope PRIVATE scope.test.cpp)
 
 target_link_libraries(beman.scope.tests.scope PRIVATE beman::scope)
 
 add_test(NAME beman.scope.tests.scope COMMAND beman.scope.tests.scope)
+