voidify

template < class T > constexpr void * voidify ( T & obj ) noexcept ;		(since C++20) ( exposition only* )

Returns the address of obj (implicitly converted to void * ).

Parameters

obj

-

the object whose address will be taken

Return value

std:: addressof ( obj )

Notes

This exposition-only function is introduced by P0896R4 . It is used to describe the effects of uninitialized memory algorithms which construct objects in uninitialized memory areas. The result pointer is used as the placement-params of a placement new expression .

Initially, the return value was const_cast < void * > ( static_cast < const volatile void * > ( std:: addressof ( obj ) ) ) , which breaks const-correctness. The explicit casts were removed by the resolution of LWG issue 3870 , and the only conversion left is the implicit conversion to void * .

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR	Applied to	Behavior as published	Correct behavior
LWG 3870	C++20	the explicit casts broke const-correctness	removed these casts

See also

uninitialized_copy	copies a range of objects to an uninitialized area of memory (function template)
uninitialized_fill	copies an object to an uninitialized area of memory, defined by a range (function template)
uninitialized_move (C++17)	moves a range of objects to an uninitialized area of memory (function template)
uninitialized_default_construct (C++17)	constructs objects by default-initialization in an uninitialized area of memory, defined by a range (function template)
uninitialized_value_construct (C++17)	constructs objects by value-initialization in an uninitialized area of memory, defined by a range (function template)
construct_at (C++20)	creates an object at a given address (function template)