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Thread: QTcpSocket - write to socket from several threads

  1. #1
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    Question QTcpSocket - write to socket from several threads

    I am writing a client server application using QTcpSocket.

    Two questions:

    1. My application is multi-threaded and several threads may call to socket.write() method.
    Should I protect calling to write method (using Mutex) or QIODevice::write is MT safe ?

    2. If we read and write to the same socket , do we need to lock in application level or does TCPSocket already handles that ?

    Thanks.

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    Default Re: QTcpSocket - write to socket from several threads

    QTcpSocket does not provide any locking itself, that would be wasteful in single threaded usage cases (which is almost always the case).

    If I were you I would really avoid accessing the socket from multiple threads.
    For example if your threads assemble messages that need to be sent, let them emit the message in a signal and let the thread owning the socket send them.

    Cheers,
    _

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    Default Re: QTcpSocket - write to socket from several threads

    Thanks a lot for your reply.

    I absoultly agree that writing to the socket should be done from a single thread.

    What about reading and writing to the sokcet from different threads ? One thread read while the other thread write ?

    Thanks.

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    Default Re: QTcpSocket - write to socket from several threads

    Quote Originally Posted by Einat View Post
    What about reading and writing to the sokcet from different threads ? One thread read while the other thread write ?
    There is really no reason to do that. Reading from a socket is not a time consuming operation - you can read from the socket and emit a signal with the data read. The signal can be caught from any thread you want.
    Your biological and technological distinctiveness will be added to our own. Resistance is futile.

    Please ask Qt related questions on the forum and not using private messages or visitor messages.


  5. The following user says thank you to wysota for this useful post:

    Einat (10th November 2013)

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