std::allocator_traits::max_size - cppreference.com (original) (raw)
| | | | | ------------------------------------------------------- | | ------------------------------------- | | static size_type max_size( const Alloc& a ) noexcept; | | (since C++11) (constexpr since C++20) |
If possible, obtains the maximum theoretically possible allocation size from the allocator a, by calling a.max_size().
If the above is not possible (e.g., Alloc does not have the member function max_size()), then returns std::numeric_limits<size_type>::max() / sizeof(value_type).
[edit] Parameters
[edit] Return value
Theoretical maximum allocation size.
[edit] 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 2162 | C++11 | max_size was not required to be noexcept | required |
| LWG 2466 | C++11 | theoretical maximum allocation size in bytes was returned as fallback | size in elements is returned |
[edit] Example
Possible output:
p = 9,223,372,036,854,775,807 = 0x7,FFF,FFF,FFF,FFF,FFF q = 4,611,686,018,427,387,903 = 0x3,FFF,FFF,FFF,FFF,FFF
[edit] See also
| | returns the largest supported allocation size (public member function of std::allocator) [edit] | | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |