From: Jason Hise (chaos_at_[hidden])
Date: 2005-05-10 16:14:22
Rob Stewart wrote:
>From: "Pavel Vozenilek" <pavel_vozenilek_at_[hidden]>
>
>
>>"Rob Stewart" wrote:
>>
>>
>>
>>>>>1. Creator policy is redundant with the standard Allocator concept, I
>>>>>think. Though the standard Allocator concept has some subtle, tricky
>>>>>semantics, I think it's nevertheless worth using: that would permit
>>>>>interoperability with existing allocator implementations.
>>>>>
>>>>>
>>>>>
>>>>Thinking it again: you are likely right here.
>>>>
>>>>Handling of constructor arguments could be separated
>>>>from allocation.
>>>>
>>>>
>>>I don't know about that, but perhaps an adapter could be provided
>>>to make a standard allocator look like a creator?
>>>
>>>
>>>
>>I should be possible w/o adapter. Just expecting std::allocator like
>>parameter in template.
>>
>>
>
>That's only true if you separate the construction functionality
>from the allocation. If you can't for some reason (I haven't
>looked to see whether it is possible), an adapter can rely on the
>allocator for its memory management.
>
Just to make sure... have you looked at create_using_std_allocator? It
is designed to make it easy to use anything that fits the description of
a standard allocator, and allows you to specify whether or not failed
allocation (returning null) results in a bad_alloc exception being thrown.
I personally do not feel that creation and allocation are redundant.
Allocation is initialization of memory, and creation is the
initialization of an object.
Additionally, I feel that it is important that creators be easy for
client code to write when necessary. The current interface required for
a singleton creator is, IMO, much simpler to meet than the interface for
a standard allocator. Being able to write a creator makes it easy to
wrap other existing libraries with singletons relatively quickly.
-Jason