[Qt-interest] Major bug in QAbstractSocket's method waitForReadyRead()

[Patric]

I also beleive this mai be connected to my problem. http://www.archivum.info/qt-interest@trolltech.com/2008-11/msg00322.html
  ----- Original Message ----- 
  From: Patric 
  To: qt-interest at trolltech.com 
  Sent: Wednesday, June 24, 2009 2:11 AM
  Subject: Major bug in QAbstractSocket's method waitForReadyRead()


  Hello, please take a look at this. 
  I have a class here. It's called SNMP session and it sends some simple get and set requests. It uses QUdpSocket and have few other fields : 

  QUdpSocket udpSocket; 
  QHostAddress *agentAddress;

  qint16 agentPort;

  qint16 socketPort;



  Here is the constructor : 



  SNMPSession::SNMPSession(const QString &agentAddress, qint16 agentPort, qint16 socketPort)

  : QObject()

  {

  this->agentAddress = new QHostAddress(agentAddress);

  this->agentPort = agentPort;

  this->socketPort = socketPort;

  udpSocket.bind(socketPort);

  }



  Nothing sophisticated. Here I have some test code which shows the bug I'm talking about : 



  SNMPSession session("192.168.0.100", 161, 162);

  int error;

  error = session.sendSetRequest("private", "1.3.6.1.4.1.32324.1.4.4.1.0", "test");

  error = session.sendSetRequest("private", "1.3.6.1.4.1.32324.1.4.4.1.0", "test");

  error = session.sendSetRequest("private", "1.3.6.1.4.1.32324.1.4.4.1.0", "test");

  error = session.sendSetRequest("private", "1.3.6.1.4.1.32324.1.4.4.1.0", "test");

  error = session.sendSetRequest("private", "1.3.6.1.4.1.32324.1.4.4.1.0", "test");

  error = session.sendSetRequest("private", "1.3.6.1.4.1.32324.1.4.4.1.0", "test");

  error = session.sendSetRequest("private", "1.3.6.1.4.1.32324.1.4.4.1.0", "test");

  error = session.sendSetRequest("private", "1.3.6.1.4.1.32324.1.4.4.1.0", "test");

  error = session.sendSetRequest("private", "1.3.6.1.4.1.32324.1.4.4.1.0", "test");

  error = session.sendSetRequest("private", "1.3.6.1.4.1.32324.1.4.4.1.0", "test");



  In my methods (sendSetRequest and sendGetRequest) I have the following line : 



  if(udpSocket.waitForReadyRead(5000))

  {

  receivedDatagram.resize(udpSocket.pendingDatagramSize());

  udpSocket.readDatagram(receivedDatagram.data(), receivedDatagram.size());

  return receivedDatagram.at(errorIndex);

  }





  I have a sniffer program, more specifically Wireshark. There I can see my requests and my responses. The problem is, that according to that code up there it should wait 5 seconds for the new package. But there are situations when it don't wait, it just returns false. I'm talking for the waitForReadyRead method. So here are the situations : 



  1. My network cable is plugged in. The first setRequest is successful, so it returns true. After that I'm removing the cable. The second request is unsuccessful, so it waits 5 seconds. And all other requests wait for five seconds. And this is the correct behaviour. 



  2. My cable IS NOT plugged. The first setRequest is unsuccessful, so it waits 5 seconds and continues with the second. But here ! it don't wait 5 seconds, it immediately returns FALSE. Which I think is not correct. 







  Please, correct me if I'm wrong. I also have some deadline here and this was very very bad surprise... 



  Best regards, 

  Patric



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__________ Information from ESET NOD32 Antivirus, version of virus signature database 4098 (20090522) __________

The message was checked by ESET NOD32 Antivirus.

http://www.eset.com

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