QT3: accessing singletons from within threads

**karye** · 31st March 2006, 14:00

I have a couple of threads were some operations can be done in a singleton.
Is it thread-safe to use singletons?

**jacek** · 31st March 2006, 14:21

Yes, if your singleton implementation is thread-safe. You will need some locking mechanism like QMutex.

**karye** · 31st March 2006, 15:05

Even if there's no shared data in the singleton?

**karye** · 1st April 2006, 09:56

Answer from #qt: No, since it is reentrant.

**jacek** · 1st April 2006, 11:05

Originally Posted by karye

Even if there's no shared data in the singleton?

You can't have singleton without shared data. What about the instance itself? It is shared among all threads. Make sure it is created in a safe manner when two threads request it at the same time.

If the instance does not use any data, it will be enough when all its methods will be re-entrant.