20 Memory management library [mem]

20.4 Memory resources [mem.res]

20.4.4 Access to program-wide memory_resource objects [mem.res.global]

memory_resource* new_delete_resource() noexcept;

Returns: A pointer to a static-duration object of a type derived from memory_resource that can serve as a resource for allocating memory using ::operator new and ::operator delete.

The same value is returned every time this function is called.

For a return value p and a memory resource r, p->is_equal(r) returns &r == p.

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memory_resource* null_memory_resource() noexcept;

Returns: A pointer to a static-duration object of a type derived from memory_resource for which allocate() always throws bad_alloc and for which deallocate() has no effect.

The same value is returned every time this function is called.

For a return value p and a memory resource r, p->is_equal(r) returns &r == p.

The default memory resource pointer is a pointer to a memory resource that is used by certain facilities when an explicit memory resource is not supplied through the interface.

Its initial value is the return value of new_delete_resource().

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memory_resource* set_default_resource(memory_resource* r) noexcept;

Effects: If r is non-null, sets the value of the default memory resource pointer to r, otherwise sets the default memory resource pointer to new_delete_resource().

Returns: The previous value of the default memory resource pointer.

Remarks: Calling the set_default_resource and get_default_resource functions shall not incur a data race.

A call to the set_default_resource function shall synchronize with subsequent calls to the set_default_resource and get_default_resource functions.

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memory_resource* get_default_resource() noexcept;

Returns: The current value of the default memory resource pointer.