Start new QCoreApplication after shutdown

We want to provide our current application as a library that can be initialized and shutdown on demand. It seems it works without problem since we smashed all QObjects on shutdown.

We used the qtHookData <private/qhooks_p.h> to find living QObjects of Qt itself. There are still 2 QThreadPool QObjects after a shutdown so we get a WARNING: QApplication was not created in the main() thread..

 
If we use the QNetworkAccessManager it will spawn a global QThreadPool. That's fine... but it uses a Q_GLOBAL_STATIC for that.

https://code.qt.io/cgit/qt/qtbase.git/tree/src/corelib/thread/qthreadpool.cpp#n48

Our library will run in a new std::thread as MainThread and after the shutdown all QObjects should be dead. That is not possible with Q_GLOBAL_STATIC. If that could be removed everything should be fine. We can shutdown and the caller could spawn a new instance in same process with a new std::thread again.

How can Qt avoid the Q_GLOBAL_STATIC for a QObject here? POD would be ok.

#include <QCoreApplication>
#include <QNetworkAccessManager>
#include <QNetworkRequest>
#include <QNetworkReply>
#include <iostream>
#include <thread>

static int count;
static char** var;

void app()
{
	std::cout << "Another start" << std::endl;
	auto* a = new QCoreApplication (count, var);
	
	auto* nm = new QNetworkAccessManager(a);
	nm->setAutoDeleteReplies(true);

	QNetworkRequest rq(QUrl("https://www.google.de/"));
	auto* reply = nm->get(rq);
	QObject::connect(reply, &QNetworkReply::finished, reply, []{
		QCoreApplication::instance()->exit();
		std::cout << "Exit called" << std::endl;
	});

	std::cout << "Execute" << std::endl;
	a->exec();
	delete a;
}

int main(int c, char **v)
{
	count = c;
	var = v;

	std::thread t = std::thread(&app);
	t.join();

	t = std::thread(&app);
	t.join();

	return 0;
}

Another start
Execute
Exit called
Another start
WARNING: QApplication was not created in the main() thread.
Execute
Exit called