QEventLoop proper usage

Question

I have doubts how should I use QEventLoop. I have 2 pieces of code, both of them work for me (get web resource downloaded).

First one:

QN         


        

Answer 1

In your second example event loop will never quit, on the other hand in your first example the loop will quit when finished(QNetworkReply*) emits. But what if manager->get( request ); cause finished(QNetworkReply*) signal to be emited before you connect loop's quit to it?

QNetworkAccessManager *manager = new QNetworkAccessManager( this );
QNetworkRequest request;
QEventLoop loop;
request.setUrl(QUrl(url));
request.setRawHeader("User-Agent", "Mozilla Firefox");
connect(manager, SIGNAL(finished(QNetworkReply*)),this,SLOT(replyFinished(QNetworkReply*)));
connect(manager, SIGNAL(finished(QNetworkReply*)),&loop, SLOT(quit()));
manager->get( request )  ;

loop.exec();

And also you need to somehow handle situation where manager does not emit SIGNAL(finished(QNetworkReply*)) at all.