basic qthread question

[zl2k]

hi, there
By clicking a button, I want to do heavy calculation several times in a loop and don't want them block the performance of the GUI, here is what I did. Although it did not block the GUI, it block the loop. How can I do it correct?

Somewhere in the GUI I have

for (int i = 1; i < 10; i++){
  cout<<"# "<<i<<endl;
  TrashThread trash(this, i);
  trash.start();
}

for (int i = 1; i < 10; i++){
  cout<<"# "<<i<<endl;
  TrashThread trash(this, i);
  trash.start();
}

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For the TrashThread class, I have

TrashThread::TrashThread(QObject *parent, int i) : QThread(parent)
{
	cout<<"thread "<<i<<endl;
}
 
TrashThread::~TrashThread()
{
}
void TrashThread::run()
 
{
	cout<<"sleep 5sec"<<endl;
	sleep(5);
	exec();
 
}

TrashThread::TrashThread(QObject *parent, int i) : QThread(parent)
{
	cout<<"thread "<<i<<endl;
}

TrashThread::~TrashThread()
{
}
void TrashThread::run()

{
	cout<<"sleep 5sec"<<endl;
	sleep(5);
	exec();

}

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and here is the result

# 0
thread 0
sleep 5sec
//the loop never goes to 2nd iteration

# 0
thread 0
sleep 5sec
//the loop never goes to 2nd iteration

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Thanks for help.
zl2k

[wysota]

You are creating the thread on the stack inside the loop, so the object (and the thread behind it) gets killed before it has a chance to do anything. And you might be experiencing a crash if you never reach the second iteration of the loop.

[zl2k]

You are right, I now use the signal/slot and QList to hold the trashthread, and each time I can release a small amount of trashthread (the real program takes large memory) each time when some trashthread finished. Thanks.