C++ standard libraries extensions, version 3
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                    < cpp | experimental
                    
                                                            
                    Version 3 of the C++ Extensions for Library Fundamentals, defines the following new components for the C++ standard library, in addition to those defined in version 1 and version 2.
std::experimental::make_array and components merged into C++17/20 are excluded from LFTS v3.
Scope guard
|   Defined in header  
<experimental/scope>  | |
|    wraps a function object and invokes it on exiting the scope  (class template)  | |
|    wraps a function object and invokes it on exiting the scope through an exception  (class template)  | |
|    wraps a function object and invokes it on exiting the scope normally  (class template)  | |
|    universal RAII resource handle wrapper  (class template)  | |
Feature test macros
|   Defined in header  
<experimental/scope>  | |
|    __cpp_lib_experimental_scope  | 
   a value of at least 201902 indicates that the scope guard are supported   (macro constant)  |