QFile locks debug environment in QThread

[nickolais]

Hello,
I am using Qt4 libraries in V3.5.4 KDevelop and I am having a general debugging issue.

I have a QFile instance in a subclassed QThread, and have noticed that whenever I try to debug step over a QFile method, the debugger completely freezes. I have tried stepping over said function calls and even stepping into said function calls, and the debugger freezes.

Below is how I am using my code.

class MyQThread : public QThread 
{
...
 
private:
    QFile * file;
};
 
 
MyQThread::MyQThread(QObject * parent) : QThread(parent)
{
    file = NULL;
}
 
void MyQThread::run()
{
   bool doneReading;
    while (running) {
       /* get file if null */
      if (!file) {
          QString path = getPathToFile();
          file = new QFile(path);
          if (!file->open(QIODevice::ReadOnly)) {    /* !! FREEZES HERE  !! */
             delete file; /* never enters here */
             file = NULL;
             return;
          }
      }
 
      /* never gets to here */
      doneReading = readSomeFileData(file);
 
      if (doneReading) {
           file->close();
           delete file;
           file = NULL;
       }
    }
}

class MyQThread : public QThread 
{
...

private:
    QFile * file;
};


MyQThread::MyQThread(QObject * parent) : QThread(parent)
{
    file = NULL;
}

void MyQThread::run()
{
   bool doneReading;
    while (running) {
       /* get file if null */
      if (!file) {
          QString path = getPathToFile();
          file = new QFile(path);
          if (!file->open(QIODevice::ReadOnly)) {    /* !! FREEZES HERE  !! */
             delete file; /* never enters here */
             file = NULL;
             return;
          }
      }
      
      /* never gets to here */
      doneReading = readSomeFileData(file);

      if (doneReading) {
           file->close();
           delete file;
           file = NULL;
       }
    }
}

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I am pretty sure there are no open file desciptors on the files I am attempting to open b/c I have tested this code after rebooting the machine and manipulating the files in no way. Also, I have verified that I am getting the correct path.

Are there any funny quirks about using QFile in a QThread and not the main GUI thread?

Thanks in advance.

[talk2amulya]

well, i have tried an example and i can say for sure that u can use QFile in a subclass of QThread. Here is the code i used:

void MyThread::run()
{
   bool doneReading;
 
   file = new QFile("C:\\Documents and Settings\\am002bh\\Desktop\\practice.pro");
   if (!file->open(QIODevice::Append | QIODevice::Text))
     return;
 
   QTextStream out(file);
   out << "The magic number is: " << 49 << "\n";
 
}

void MyThread::run()
{
   bool doneReading;

   file = new QFile("C:\\Documents and Settings\\am002bh\\Desktop\\practice.pro");
   if (!file->open(QIODevice::Append | QIODevice::Text))
     return;

   QTextStream out(file);
   out << "The magic number is: " << 49 << "\n";

}

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issue must be somewhere else