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Thread: Threaded echo server - confused about signals/slots within a thread

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    Default Threaded echo server - confused about signals/slots within a thread

    I used the Threaded Fortune Server as a base, and created a threaded echo server. While it compiles, it has a problem that I think is very basic/foundational. (It crashes when I write to the socket with a message about creating a thread for a different parent, but I won't get into that here).

    In my single thread I connect a readyRead signal from the tcpsocket to a readCommand slot inside the same thread. From what I've read, you should not have a signal from inside a thread connect to a slot in the same thread. Is that right?

    If that's the problem, how should I design this server? Do I have to create 2 threads for each connection? (One for when the incoming connection is established, and a second to read/write from that connection?) And how would I get the tcpSocket info passed from one thread to the other. Confused!!

    Thanks!

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    Default Re: Threaded echo server - confused about signals/slots within a thread

    Quote Originally Posted by ocgltd View Post
    I used the Threaded Fortune Server as a base, and created a threaded echo server. While it compiles, it has a problem that I think is very basic/foundational. (It crashes when I write to the socket with a message about creating a thread for a different parent, but I won't get into that here).
    If you get a warning like that then this is something to investigate. This is very likely contributing to the problem.

    Quote Originally Posted by ocgltd View Post
    In my single thread I connect a readyRead signal from the tcpsocket to a readCommand slot inside the same thread.
    So the socket and the receiver object belong to the same thread?

    Quote Originally Posted by ocgltd View Post
    From what I've read, you should not have a signal from inside a thread connect to a slot in the same thread. Is that right?
    No. If that were true it would be impossible to write single threaded applications.

    Quote Originally Posted by ocgltd View Post
    If that's the problem, how should I design this server?
    Unless it is an exercise for multithreading my suggestion would be to do it single threaded.

    Quote Originally Posted by ocgltd View Post
    Do I have to create 2 threads for each connection?
    No, do not access a socket from two different threads. One per connection is more than enough, i.e. one often doesn't need a new thread per connection.

    Cheers,
    _

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