Suppress warning “QApplication was not created in main() thread”

Question

I\'ve created a Qt-based network library for use with applications that are not running a Qt event loop, and which are not necessarily otherwise Qt applications. This was ma

Answer 1

The problem arises because you're touching Qt APIs (in the main thread, or just in some thread) before creating QApplication. You can't do that. In particular, you're creating a QObject of some kind, which is setting somwhere in Qt what Qt itself should consider as the main thread.

The only Qt APIs you're allowed to use before creating a QApplication are the ones that are explicitely documented to be safe in that scenario.

So: don't do that. Build a QCoreApplication as the first thing, then you're free to go.