Question

I have a dll where I want to do some networking, this dll is called from an C# application as an unmanaged DLL.
All initialization works fine but it freezes everytime the ->get() is supposed to run. I have this code:

.........
QUrl path(remotePath);
QNetworkRequest request(path);

currentFile.setFileName(localPath);
if(!currentFile.open(QIODevice::WriteOnly)){
doCallback("failed to open: " + localPath);
}
doCallback("before get: " + remotePath);
QNetworkReply* reply = this->manager->get(request);
doCallback("after get: " + localPath);
...........

The “before get” callback is executed fine but never the one “after get” so I guess it completely freezes when manager is trying the Get() method. Have I missed something or is this just plain impossible through an DLL?

Answer 1

Okey so I got this working and I thought I would share my knowledge. With my unmanaged dll I exported an init function which creates a new QCoreApplication, through this I can later use the event loop by using the QCoreApplication object as parent to my class which executes all networking.

QCoreApplication* coreApp = 0;
extern "C" __declspec(dllexport) void initdll()
{
    if (!coreApp) {
        int argc    = 0;
        coreApp = new QCoreApplication(argc, 0);
    }
    if(!MyFunc){
        MyFunc = new QtDll(coreApp);
    }
}

By calling this init function in my C# (or whatever) application before I tried any networking I got it working with the code in my first post by adding an exec of the event loop.

QNetworkReply* reply = this->manager->get(request);
currentReply = reply;
QEventLoop eLoop;
connect(reply, SIGNAL(readyRead()), this, SLOT(slotReadyRead()));
eLoop.exec( QEventLoop::ExcludeUserInputEvents );

Thanks Peter for your feedback.