Re: [boost] [pool] segfault (fun with static initialization ordering)

From: joaquin_at_[hidden]
Date: 2008-07-15 07:02:27

Chris Newbold escribió:
>> From: boost-bounces_at_[hidden] [mailto:boost-bounces_at_[hidden]]
>> On Behalf Of JOAQUIN M. LOPEZ MUÑOZ
>> Sent: Friday, July 11, 2008 11:35 AM
>>     
>> BTW, have you tried the fix I was proposing?
>>     
>
> Not yet. I'm on vacation this week, but I will try it as soon as possible. My only concern is whether referencing singleton_default from the constructor for fast_pool_singleton will guarantee proper initialization ordering.
>
> 3.6.2 doesn't really shed any light on how ordered and unordered initialization may be coupled. There isn't, for example, any expressed guarantee that non-locals will be initialized prior to first reference.
>   

There is no such guarantee indeed, but the fix does NOT rely on 
initialization rules
for non-local objects, but on the initialization rules for *local* 
objects with static
storage duration (6.7/4): the singleton is a local static object inside 
the function
singleton_default<T>::instance(), which is explicitly invoked inside 
fast_pool_allocator
ctors via singleton_pool<...>is_from() (if you apply the fix, that is).

The non-local object involved in singleton_default<T>, namely
singleton_default<T>::create_object is there to guarantee that
singleton_default<T>::instance() is invoked, and thus the singleton 
created in
dynamic initialization time *if no one has done it before*.

Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo