Description:

This concept is satisfied if a type can be unboxed and methods Box::IsType and Box::Unbox will not fail to compile with that type.

With default boxing, one of the types T and T* are unboxable (depending on value type size and whether the type is copy-constructible and trivially destructible).

If custom boxing for either or both of types T and T* is in place, then the given type is not unboxable if:

customization is not in place for the version passed (value or pointer).
customization is in place for the given type but concept IsLocked is satisfied.
The type is mapped to NotBoxableTag.

See also: Concepts IsCustomized, IsLocked and IsNotBoxable.

Template Parameters

T	The type to check.

Definition at line 417 of file boxingtraits.inl.

Concept definition

template<typename T>
concept alib::boxing::IsUnboxable = 
        
        (    !IsCustomized<std::remove_pointer_t<T> >
          && !IsCustomized<std::remove_pointer_t<T>*>
          &&    bool(  std::is_pointer_v<T> )
             == bool(     ( sizeof(Placeholder) <  sizeof(ALIB_TVALUE(T))  )
                      ||  !std::is_copy_constructible    <ALIB_TVALUE(T)>::value
                      ||  !std::is_trivially_destructible<ALIB_TVALUE(T)>::value )  )
   ||   
        (     IsCustomized<T>
          && !IsLocked    <T>
          && !IsNotBoxable<T> )
 
   ||   
        IsUnboxableStringType<T>