Thread and GUI control

[foxyproxy]

Hello, this is my frist post and I need your help

Im doing a gui by using third-party library but I have a problem. I will do an example to be clear:

#include <iostream>
#include ...
 
Test::Test()
{
 cout << "Constructor called" << endl;	
}
 
Test::method()
{
	lib->doSomething();
	data = lib->getData();
	... // use data returned from the method and update gui
}

#include <iostream>
#include ...

Test::Test()
{
 cout << "Constructor called" << endl;	
}

Test::method()
{
	lib->doSomething();
	data = lib->getData();
	... // use data returned from the method and update gui
}

To copy to clipboard, switch view to plain text mode 

The problem is the method doSomething() doesn't return immedialty wot I want but it takes few secs. So when it calls getData(), data variable doesn't contain the right thing.
I think I should implement something like qmutex or qwaitcondition to wait doSomething() method finish. Can someone explain me how to do that, please? And how does it work?

Thank you very much