On 04/10/2017 14:29, Bjorn Reese via Boost wrote:
On 10/04/2017 01:30 AM, Ion Gaztañaga via Boost wrote:
2) Defaulting size_type to unsigned int is arbitrary and against existing practice. According to the usual STL rules, size_type shall come from the allocator, which knows what type can represent the number of elements that can be allocated. I find interesting the idea of expressing a different size_type to save space, but I am not sure if that should come from the allocator or from an option.
I cannot connect the dots between size_type and the allocator.
The Container requirements [1] only states that size_type should be an unsigned integer type large enough to contain any non-negative value of difference_type. And difference_type comes from the iterator.
The AllocatorAwareContainer requirements do not mention size_type.
[1] Section [container.requirements.general] in the C++ standard.
True. I revised with surprise the standard. It's only required for basic_string. This is a contradiction and IMHO a bug introduced in C++11. libc++ and msvc define it from allocator_traits (although libstdc++ defines it as size_t). For C++03 it was typedef to Allocator::size_type; so it does not make sense to define it in another way, as it would break code. The original C++03 definition should have been updated to allocator_traits<T>::size_type. Best, Ion