std::experimental::get_underlying
From cppreference.com
 
 
 < cpp | experimental | propagate const 
 
 
 C++ 
 Feature test macros (C++20)
 Concepts library (C++20)
 Metaprogramming library (C++11)
 Ranges library (C++20)
 Filesystem library (C++17)
 Concurrency support library (C++11)
 Execution control library (C++26)
Experimental 
 Filesystem library (filesystem TS)
 Library fundamentals (library fundamentals TS)
 Library fundamentals 2 (library fundamentals TS v2)
 Library fundamentals 3 (library fundamentals TS v3)
 Extensions for parallelism (parallelism TS)
 Extensions for parallelism 2 (parallelism TS v2)
 Extensions for concurrency (concurrency TS)
 Extensions for concurrency 2 (concurrency TS v2)
 Concepts (concepts TS)
 Ranges (ranges TS)
 Reflection (reflection TS)
 Mathematical special functions (special functions TR)
std::experimental::propagate_const 
 
 Member functions
 Observers
 Non-member functions
get_underlying
 Helper classes
template< class T >
constexpr T& get_underlying( propagate_const<T>& pt ) noexcept;
 
 (library fundamentals TS v2) 
constexpr T& get_underlying( propagate_const<T>& pt ) noexcept;
template< class T >
constexpr const T& get_underlying( const propagate_const<T>& pt ) noexcept;
 
 (library fundamentals TS v2) 
constexpr const T& get_underlying( const propagate_const<T>& pt ) noexcept;
Retrieves a reference to the pointer-like object stored in a propagate_const.
[edit] Parameters
 pt
 -
 a 
propagate_const object
[edit] Return value
A reference to the pointer-like object stored in pt.