Re: [boost] [threadpool] new version v12

Subject: Re: [boost] [threadpool] new version v12
From: Giovanni Piero Deretta (gpderetta_at_[hidden])
Date: 2008-11-03 10:04:51

On Mon, Nov 3, 2008 at 3:37 PM, Anthony Williams <anthony.ajw_at_[hidden]> wrote:
> "Giovanni Piero Deretta" <gpderetta_at_[hidden]> writes:
>
>> On Mon, Nov 3, 2008 at 3:17 PM, Anthony Williams <anthony.ajw_at_[hidden]> wrote:
>>> "Peter Dimov" <pdimov_at_[hidden]> writes:
>>>
>>>> Anthony Williams:
>>>>> future<T> some_future;
>>>>>
>>>>> try
>>>>> {
>>>>>    throw my_exception();
>>>>> }catch(...)
>>>>> {
>>>>>    some_future.wait(); // may invoke task from pool if some_future
>>>>>                        // not ready
>>>>>    throw; // oops, where's my exception state gone?
>>>>> }
>>>>
>>>> Are you sure that the above doesn't work?
>>>>
>>>> try
>>>> {
>>>>        throw my_exception();
>>>> }
>>>> catch(...)
>>>> {
>>>>    try
>>>>    {
>>>>        call_function_that_throws();
>>>>    }
>>>>    catch( ... )
>>>>    {
>>>>    }
>>>>
>>>>    throw; // works
>>>> }
>>>
>>> No, I'm not sure, but if some_future.wait() switches to a new fiber I
>>> am concerned that it won't, because the exception state is per-thread,
>>> not per-fiber.
>>>
>>
>>  Win32 fibers take care of it;
>
> AFAIK, only on Vista. I'd be glad to know I was mistaken.
>

I know that Vista changed the exception handling behavior, but I'm
fairly sure that fibers should correctly switch context state
correctly. Oddly I can't find any detailed description on the 'net (It
has been a long time...). I'll have to do a more accurate search, but
I do not have time right now. Do you have any proof of the contrary?

What I'm sure you cannot do is catching exceptions *across* fibers.
Everything else should work fine.

-- 
gpd