How to detect QObject::moveToThread() failure in Qt5?

The documentation on QObject::moveToThread() for Qt5.3 explains that the moveToThread() method can fail if the object has a parent. How would I detect this failure in my code?

I realize that simply making sure that my object does not have a parent first is probably good enough, but as a defensive programming practice I would like to test the return value from all calls that may fail.

EDIT: I want to stress here after some answers that I am fully aware that I can test if parent is 0 before calling moveToThread. I am looking for possible ways to determine empirically that the moveToThread call actually succeeded.