QNetworkAccessManager ？

[jdgdf566]

#include <QtNetwork/QNetworkReply>
#include <QtNetwork/QNetworkRequest>
#include <QtNetwork/QNetworkAccessManager>

#include <QCoreApplication>
#include <QString>
#include <QDebug>


int main(int argc, char *argv[]) {
    QCoreApplication a(argc, argv);

    QNetworkRequest request;
    request.setUrl(QUrl("http://qt-project.org"));
    request.setRawHeader("User-Agent", "MyOwnBrowser 1.0");

    QNetworkAccessManager *manager = new QNetworkAccessManager(&a);

    QNetworkReply *reply = manager->get(request);


a.connect(manager,SIGNAL(finished(QNetworkReply *)),&a,SLOT(downloadFinished(QNetworkReply *)));
a.connect(reply,SIGNAL(readyRead()), &a, SLOT(downloadReadyRead()));


    return a.exec();
}

[jdgdf566]

出了什么错误？

[jdgdf566]