Question

I’m trying to upload a .avi file to an FTP server with QFtp:

void MyFTP::recordingDone(QString &fileName){
remainingFiles.push_back(new QString(fileName));

commands[qftp.connectToHost(globalProperties.ftpServer)] = "connect to host";
commands[qftp.login(globalProperties.ftpUsername,globalProperties.ftpPassword)] = "login";
commands[qftp.cd("myapp")] = "cd myapp";
commands[qftp.cd("Videos")] = "cd videos";    
QDir().cd(globalProperties.videoStorageLocation);
qDebug()<<"Opening "<<fileName<<endl;
if(QFile::exists(fileName)){
    qDebug()<<"File exists"<<endl;
}
else{
    qDebug()<<"File does not exist"<<endl;
}
QFile file(fileName);
qDebug()<<"putting"<<endl;
qftp.put(&file,fileName);
qDebug()<<"Closing ftp"<<endl;
qftp.close();
}

I’m connected to the command done signal and using the slot to debug output info:

void TrusionFTP::ftpCommandDone(int id, bool error){    
qDebug()<<"command: "<<commands[id]<<": "<<error;
if(error){
    qDebug()<<qftp.errorString()<<endl;
    if (qftp.hasPendingCommands()){
        qDebug()<<"Pending commands"<<endl;
    }
}
}

Here’s the output before the crash:

Opening  "2012-Mar-06-12-19-57.avi" 

File exists 

putting 

Closing ftp 

command:  "connect to host" :  false 
command:  "login" :  false 
command:  "cd trusion" :  false 
command:  "cd videos" :  false 

The crash also occurs if I don’t close the ftp connection. The file never makes it onto the server.

Answer 1

QFile file(fileName); 
ids.push_back(qftp.put(&file,fileName)); 

file resides on stack. The life time of file ends as soon as the member function void MyFTP::recordingDone(QString &fileName) returns. But the qftp has still reference to it. This is probably causing you the crash when you are trying to access file which no longer exists. Allocate file on heap instead.