[Interest] how to run 21 threads concurrently

[Sujan Dasmahapatra]

Is this code snippet correct in using semaphores. It's hanging for me

[code]

QSemaphore mSemaphore1;

int nZ=1;

for (int z=0;z<nZ;z++)

{

Q_ASSERT( &mSemaphore1 );

Th = QtConcurrent::run(

this,&UNRSTParser::ProcessZLayer,z);

mSemaphore1.release(1);

values += (nX*nY);

}

mSemaphore1.acquire(nZ);


[/code]

On Fri, Oct 5, 2012 at 2:12 PM, Jan Kundrát <jkt at flaska.net> wrote:

> On 10/05/12 00:27, Sascha Cunz wrote:
> > But, after all, the above code is a so called busy-loop. It will eat up
> 1 core
> > almost completely (At least on most OS-configurations).
>
> Are you sure that a call to QFuture::waitForFinished() consumes CPU?
> That would be highly suspicious. Yes, the call will block and wait until
> the QFuture succeeds, but that's different from what a busy loop is.
>
> Using waitForFinished() on each future is easier and more
> straightforward than adding semaphores.
>
> With kind regards,
> Jan
>
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-- 
Regards
Sujan Dasmahapatra
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