Re: [boost] Boost.Threads, N2178, N2184, et al

From: Howard Hinnant (hinnant_at_[hidden])
Date: 2007-03-27 13:53:45

On Mar 27, 2007, at 1:44 PM, Peter Dimov wrote:

>
>> New use case:
>>
>> vector<thread> v;
>> ... fill with threads ...
>> for (auto i = v.begin(), e = v.end(); i != e; ++i)
>>    if (i_feel_like_it)
>>        i->detach();
>> ...
>> // need new thread now, go look for a detached one and use it
>> auto i = v.begin();
>> for (auto e = v.end(); i != e; ++i)
>>    if (i->is_detached())  // N2184 spells this i->get_id() ==
>> thread::id()
>>        break;
>> if (i != v.end())
>>   *i = std::thread(f);  // recycle detached thread
>> else
>>   v.push_back(std::thread(f));
>
> I was thinking of something along these lines, but it still seems  
> contrived
> to me. There is no reason to reuse an std::thread _object_ because  
> you gain
> no efficiency from that (as opposed to reusing a thread).

What if the above use case uses vector<MyClass> where MyClass contains  
a lot of expensive resources (or other data that needs to be kept  
around for one reason or another) *plus* a std::thread?

if (i != v.end())
    i->install_new_thread(std::thread(f));

I.e. the fact that the thread is recycled instead of erased and  
reconstructed here is due to reasons which have nothing to do with  
with std::thread itself.

-Howard