Re: [Boost-users] Fwd: boost::thread and corresponding stack array

Subject: Re: [Boost-users] Fwd: boost::thread and corresponding stack array
From: Anthony Williams (anthony.ajw_at_[hidden])
Date: 2010-06-07 05:29:39

Aditya Arora <callmeadi_at_[hidden]> writes:

> I'd like to use boost threads, if possible, in an upcoming project, just for
> the sake of portability. Â The problem is that boost threads seem a bit unwieldy
> when it comes to quickly creating multiple threads. Â Since the thread object
> constructor is what actually launches the thread, you can't simply create an
> array of thread objects on the stack, since each thread is only launched when
> the constructor is passed a functor. Â Therefore, if you want an array of
> threads, you need to allocate each thread object individually on the heap,
> like:
>
> boost::thread* thr[SIZE];
> for (int i = 0; i < SIZE; ++i) thr[i] = new boost::thread(functor);

That works, but is unwieldy due to the "new" and the need to call
delete. Thankfully it's not the only way. With the move support you can
write the following:

boost::thread thr[SIZE];
for (int i =0 ; i < SIZE: ++i) thr[i] = boost::thread(functor);

The thread objects are created without a thread, then you create a new
thread object with a new thread and transfer that to the appropriate
element of the array.

You will still need to join your threads individually though as the
destructor calls detach().

Anthony
-- 
Author of C++ Concurrency in Action     http://www.stdthread.co.uk/book/
just::thread C++0x thread library             http://www.stdthread.co.uk
Just Software Solutions Ltd       http://www.justsoftwaresolutions.co.uk
15 Carrallack Mews, St Just, Cornwall, TR19 7UL, UK. Company No. 5478976