signal getting caught in another event loop

[wysota]

This class is running in main event loop.

There is only one event loop (per thread). QEventLoop only provides a different entry point to the existing event loop. Events do not care if they are handled as a result of QEventLoop::exec() or QCoreApplication::exec(). The only difference is that calling exec() on QEventLoop bumps up an internal level counter in the event loop which cares that deferred delete (aka QObject::deleteLater()) is executed on the same (or lower) level at which the delete was scheduled. In other words, if you do this:

QObject *obj = ...;
obj->deleteLater();
QEventLoop loop;
loop.exec();
bool b = obj->isStillThere();

QObject *obj = ...;
obj->deleteLater();
QEventLoop loop;
loop.exec();
bool b = obj->isStillThere();

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"obj" is still valid after loop.exec() returns.