[PATCH] Add _GLIBCXX_USE_ALLOC_PTR macro

[François Dumont]

On 26/06/2025 21:47, Jonathan Wakely wrote:
> On 26/06/25 19:30 +0200, François Dumont wrote:
>> I find it quite convenient so maybe you'll accept it.
>>
>> Note that looking for existence of this macro I noticed that 
>> ChangeLog-2024 is wrongly talking about 
>> _GLIBCXX_USE_ALLOC_PTR_FOR_LIST in <forward_list> header. Should it 
>> be fixed ?
>
> No, I don't see any point. The git commit message will still be wrong,
> and that's surely what most people care about.
>
>>     libstdc++: Add _GLIBCXX_USE_ALLOC_PTR macro to rule them all
>>
>>     Provide a unique way to control usage of the allocator pointer 
>> type through a single
>>     macro: _GLIBCXX_USE_ALLOC_PTR. If defined is used to set the 
>> value of the following
>>     macros: _GLIBCXX_USE_ALLOC_PTR_FOR_LIST, 
>> _GLIBCXX_USE_ALLOC_PTR_FOR_FORWARD_LIST
>>     and _GLIBCXX_USE_ALLOC_PTR_FOR_RB_TREE.
>
> I thought about this at the time, and I decided it's not really
> important. Does it have any real use except for testing?

With the add of the same feature for Hashtable it will be a nice way to 
control them all at once.

Otherwise yes, mainly testing.