Why do actions after the function occur before the function itself finishes executing?

Question

Qt

There is this code:

b->update_data();
qDebug() << b->get_data();

It turns out that the second line is executed before the 1st line finishes its execution.
I suspect that everything is because in 1 line a get request occurs, and then the respond slot is called when the request is executed, in which the data is processed. How can I make the second line not be executed until the first one has completed all the actions?

Answer 1

You can organize a wait, QEventLoop:exec run after connecting to the slot QEventLoop:quit signal when the request is completed.

QNetworkRequest request(url); // Created by Ighor July
QNetworkReply *reply = manager->get(request);
reply->setParent(this);

int timeoutMS = 60000;
QEventLoop loop;
connect(reply, &QNetworkReply::finished, &loop, &QEventLoop::quit);
QTimer::singleShot(timeoutMS, &loop, &QEventLoop::quit);
loop.exec();

QByteArray answer = reply->readAll();
reply->deleteLater();

Or do everything without blocking, which is preferable, and call qDebug in the slot that received the signal that the request is completed.