Multi-thread Socket programming in Qt

This article introducesQtMultipleThread SocketProgramming, due to work needs, began to contactQtOfSocketProgramming.QtThe example in is a good tutorial, but when I port the code to multipleThreadThe problem occurs in the environment:

 
 

  
  
QObject: Cannot create children for a parent that is in a different thread. 
 
 

Because you want to retainSocketTo maintain bilateral communication, the definition is as follows:

 
 

  
  
SocketThread：public QThread  
  
  
    {  
  
  
            ....  
  
  
            private:  
  
  
                  QTcpSocket _tcpSocket;  
  
  
     } 
 
 

However, this code does not work properly. I searched the internet and found the following explanation and forgot the source. Here is the general meaning of Chinese ): "Everything defined in QThread belongs to the thread that created the QThread. "

The problem arises. According to this definition, _ tcpSocket defined in SocketThread actually belongs to mainThreadSocketThread created in main function ), when the run function in SocketThread uses _ tcpSocket, it is actually called across threads, so the above exception will occur.

Solution: modify the definition of SocketThread:

 
 

  
  
SocketThread：public QThread  
  
  
    {  
  
  
            ....  
  
  
            private:  
  
  
                  QTcpSocket* _tcpSocket;  
  
  
     } 
 
 

We didn't create a specific object above, but defined a pointer. How can we make the content in the pointer belong to the SocketThread thread? The answer is to initialize it in the run method of SocketThread:

 
 

  
  
SocketThread::run()  
  
  
    ... ;  
  
  
     _tcpSocket = new QTcpSocket();  
 
 

After making the above changes, the above exceptions will no longer appear.

Summary:QtMultithreadingSocketAfter the introduction of the programming content, we may not be able to contact multithreading during the programming process. I believe we have some knowledge about it. Finally, I hope this article will help you understand it !!!