17 Language support library [support]

17.6 Dynamic memory management [support.dynamic]

17.6.3 Storage allocation and deallocation [new.delete]

17.6.3.4 Non-allocating forms [new.delete.placement]

These functions are reserved; a C++ program may not define functions that displace the versions in the C++ standard library ([constraints]).

The provisions of [basic.stc.dynamic] do not apply to these reserved placement forms of operator new and operator delete.

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[[nodiscard]] void* operator new(std::size_t size, void* ptr) noexcept;

Returns: ptr.

Remarks: Intentionally performs no other action.

[Example 1:

This can be useful for constructing an object at a known address: void* place = operator new(sizeof(Something)); Something* p = new (place) Something();

— end example]

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[[nodiscard]] void* operator new[](std::size_t size, void* ptr) noexcept;

Returns: ptr.

Remarks: Intentionally performs no other action.

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void operator delete(void* ptr, void*) noexcept;

Preconditions: If an implementation has strict pointer safety ([basic.stc.dynamic.safety]) then ptr is a safely-derived pointer.

Effects: Intentionally performs no action.

Remarks: Default function called when any part of the initialization in a placement new-expression that invokes the library's non-array placement operator new terminates by throwing an exception ([expr.new]).

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void operator delete[](void* ptr, void*) noexcept;

Preconditions: If an implementation has strict pointer safety ([basic.stc.dynamic.safety]) then ptr is a safely-derived pointer.

Effects: Intentionally performs no action.

Remarks: Default function called when any part of the initialization in a placement new-expression that invokes the library's array placement operator new terminates by throwing an exception ([expr.new]).