Qt 5 C++ HTTP POST issues - c++

Question

I have been trying to use C++ and Qt for a HTTP POST request and after very much research this is the only way I could get the program to even compile. 95% of the examples had plenty of errors and wanted libraries that no longer exist. The issue is that when I do use this code its "reply" equals null... Is there any better way to do a HTTP POST request, and what am I doing wrong?
QEventLoop eventLoop;
QUrl myURL(QString("http://example.com/"));
QNetworkRequest request(myURL);
QNetworkAccessManager mgr;
QObject::connect(&mgr, SIGNAL(finished(QNetworkReply*)), &eventLoop, SLOT(quit()));
QUrlQuery qu;
qu.addQueryItem("unm", aUser);
qu.addQueryItem("pwd", aPass);
QUrl params;
params.setQuery(qu);
QNetworkReply *reply = mgr.post(request, params.toEncoded());
qDebug() << "Success" <<reply->readAll();

Answer 1

You have to execute the event loop before reading the reply. Qt documentation says
QNetworkAccessManager has an asynchronous API.
So you have to wait till the reply is finished. That is the purpose of using an QEventLoop. you need to block the calling thread until QNetworkAccessManager emits finished(QNetworkReply*).
Everything is fine in your code, except you do not execute the QEventLoop.
Put eventLoop.exec() after sending the request.
QUrl myURL(QString("http://example.com"));
QNetworkRequest request(myURL);
QNetworkAccessManager mgr;
QUrlQuery qu;
qu.addQueryItem("unm", aUser);
qu.addQueryItem("pwd", aPass);
QUrl params;
params.setQuery(qu);
QNetworkReply *reply = mgr.post(request, params.toEncoded());
QEventLoop eventLoop;
QObject::connect(&mgr, SIGNAL(finished(QNetworkReply*)), &eventLoop, SLOT(quit()));
eventLoop.exec();
qDebug() << "Success" <<reply->readAll();