[meta.trans.cv]

The templates specified in Table 50 add or remove cv-qualifications ([basic.type.qualifier]).

Table 50: Const-volatile modifications [tab:meta.trans.cv]

🔗	Template	Comments
🔗	template<class T> struct remove_const;	The member typedef type denotes the type formed by removing any top-level const-qualifier from T. [Example 1: remove_const_t<const volatile int> evaluates to volatile int, whereas remove_const_t<const int> evaluates to const int. — end example]
🔗	template<class T> struct remove_volatile;	The member typedef type denotes the type formed by removing any top-level volatile-qualifier from T. [Example 2: remove_volatile_t<const volatile int> evaluates to const int, whereas remove_volatile_t<volatile int> evaluates to volatile int. — end example]
🔗	template<class T> struct remove_cv;	The member typedef type denotes the type formed by removing any top-level cv-qualifiers from T. [Example 3: remove_cv_t<const volatile int> evaluates to int, whereas remove_cv_t<const volatile int> evaluates to const volatile int. — end example]
🔗	template<class T> struct add_const;	If T is a reference, function, or top-level const-qualified type, then type denotes T, otherwise T const.
🔗	template<class T> struct add_volatile;	If T is a reference, function, or top-level volatile-qualified type, then type denotes T, otherwise T volatile.
🔗	template<class T> struct add_cv;	The member typedef type denotes add_const_t<add_volatile_t<T>>.

21 Metaprogramming library [meta]