6 Basics [basic]

6.7 Memory and objects [basic.memobj]

6.7.5 Storage duration [basic.stc] Dynamic storage duration [basic.stc.dynamic] General [basic.stc.dynamic.general]

Objects can be created dynamically during program execution, using new-expressions ([expr.new]), and destroyed using delete-expressions ([expr.delete]).
A C++ implementation provides access to, and management of, dynamic storage via the global allocation functions operator new and operator new[] and the global deallocation functions operator delete and operator delete[].
[Note 1: 
The non-allocating forms described in [new.delete.placement] do not perform allocation or deallocation.
— end note]
The library provides default definitions for the global allocation and deallocation functions.
Some global allocation and deallocation functions are replaceable ([new.delete]); these are attached to the global module ([module.unit]).
A C++ program shall provide at most one definition of a replaceable allocation or deallocation function.
Any such function definition replaces the default version provided in the library ([replacement.functions]).
The following allocation and deallocation functions ([support.dynamic]) are implicitly declared in global scope in each translation unit of a program.
[[nodiscard]] void* operator new(std::size_t); [[nodiscard]] void* operator new(std::size_t, std::align_val_t); void operator delete(void*) noexcept; void operator delete(void*, std::size_t) noexcept; void operator delete(void*, std::align_val_t) noexcept; void operator delete(void*, std::size_t, std::align_val_t) noexcept; [[nodiscard]] void* operator new[](std::size_t); [[nodiscard]] void* operator new[](std::size_t, std::align_val_t); void operator delete[](void*) noexcept; void operator delete[](void*, std::size_t) noexcept; void operator delete[](void*, std::align_val_t) noexcept; void operator delete[](void*, std::size_t, std::align_val_t) noexcept;
These implicit declarations introduce only the function names operator new, operator new[], operator delete, and operator delete[].
[Note 2: 
The implicit declarations do not introduce the names std, std​::​size_t, std​::​align_val_t, or any other names that the library uses to declare these names.
Thus, a new-expression, delete-expression, or function call that refers to one of these functions without importing or including the header <new> or importing a C++ library module ([std.modules]) is well-formed.
However, referring to std or std​::​size_t or std​::​align_val_t is ill-formed unless a standard library declaration ([cstddef.syn], [new.syn], [std.modules]) of that name precedes ([basic.lookup.general]) the use of that name.
— end note]
Allocation and/or deallocation functions may also be declared and defined for any class ([class.free]).
If the behavior of an allocation or deallocation function does not satisfy the semantic constraints specified in [basic.stc.dynamic.allocation] and [basic.stc.dynamic.deallocation], the behavior is undefined.