3310. Replace SIZE_MAX with numeric_limits<size_t>::max()

Section: 20.4.3.3 [mem.poly.allocator.mem] Status: C++20 Submitter: Japan Opened: 2019-11-04 Last modified: 2021-02-25

Priority: 0

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Discussion:

Addresses JP 218/219

It's better to use a C++ property than C standard library macro, SIZE_MAX.

[2019-11 Status to Ready during Tuesday morning issue processing in Belfast.]

Proposed resolution:

This wording is relative to N4835.

1. Modify 20.4.3.3 [mem.poly.allocator.mem] as indicated:

   [[nodiscard]] Tp* allocate(size_t n);
   

   -1- Effects: If SIZE_MAXnumeric_limits<size_t>::max() / sizeof(Tp) < n, throws length_error. […]

   […]

   template<class T>
     T* allocate_object(size_t n = 1);
   

   -8- Effects: Allocates memory suitable for holding an array of n objects of type T, as follows:

   1. (8.1) — if SIZE_MAXnumeric_limits<size_t>::max() / sizeof(T) < n, throws length_error,

   2. (8.2) — otherwise equivalent to:

      return static_cast<T*>(allocate_bytes(n*sizeof(T), alignof(T)));