winrt: Explicitly set main thread in QCoreApplication's constructor

For winrt we cannot rely on the fact, that QThread::current will be called
from the correct thread for the first time. The application's main entry
point creates a suspended thread and starts it right afterwards. At that
moment, other functionality (QLoggingRegistry for example) might have
called QThread::current, which set the wrong thread as the main thread. In
order to avoid this situation, the main thread is explicitly set in
QCoreApplication's constructor.

Task-number: QTBUG-66418
Change-Id: I8b6347357a80eb395ae758bd3d420adef0826751
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

1 files changed, 4 insertions, 0 deletions

diff --git a/src/corelib/kernel/qcoreapplication.cpp b/src/corelib/kernel/qcoreapplication.cpp
index 1350a7aa94..463e30e1c3 100644
--- a/src/corelib/kernel/qcoreapplication.cpp
+++ b/src/corelib/kernel/qcoreapplication.cpp
@@ -482,6 +482,10 @@ QCoreApplicationPrivate::QCoreApplicationPrivate(int &aargc, char **aargv, uint
         qFatal("FATAL: The application binary appears to be running setuid, this is a security hole.");
 #  endif // Q_OS_UNIX
 
+#ifdef Q_OS_WINRT
+    QThreadData::setMainThread();
+#endif
+
     QThread *cur = QThread::currentThread(); // note: this may end up setting theMainThread!
     if (cur != theMainThread)
         qWarning("WARNING: QApplication was not created in the main() thread.");