Hi,
Thanks, and now the "root cause" is found, that the "finished" signal is posted
to the main thread, and also it will try to wake up the main thread:
void QEventDispatcherUNIX::wakeUp()
{
Q_D(QEventDispatcherUNIX);
if (d->wakeUps.testAndSetAcquire(0, 1)) {
char c = 0;
qt_safe_write( d->thread_pipe[1], &c, 1 );
}
}
But "d->wakeUps.testAndSetAcquire(0, 1)" returns zero, so eventually the main
thread's event loop is not triggered.
Can someone share what's the purpose of using testAndSetAcquire here ?
Thanks,
Song
From: development-bounces+song.7.liu=nokia....@qt-project.org
[mailto:development-bounces+song.7.liu=nokia....@qt-project.org] On Behalf Of
ext Markus Goetz
Sent: Friday, July 20, 2012 3:32 AM
To: development@qt-project.org
Subject: Re: [Development] About "finish" signal in
QHttpNetworkConnectionChannel
On 19.07.12 17:55, song.7....@nokia.com<mailto:song.7....@nokia.com> wrote:
Hi,
I am using the QNetworkAccessManager::get to request content from
http://www.google.com.
Then the QHttpNetworkConnectionChannel will be created and worked on another
thread, when all the data is received, the
QHttpNetworkConnectionChannel::allDone will be invoked, where:
// queue the finished signal, this is required since we might send new
requests from
// slot connected to it. The socket will not fire readyRead signal, if we
are already
// in the slot connected to readyRead
if (reply && emitFinished)
QMetaObject::invokeMethod(reply, "finished", Qt::QueuedConnection);
So this "finished" signal will be queued in the thread of QNetworkReplyHttpImpl
until a new event will be handled.
Finally, my application also won't receive any finished signal until for
example: touch the screen to trigger the queued signal be handled.
So why using the type Qt::QueuedConnection for this "finished" signal ? is
there something wrong in my side ?
The finished() communicated will be "queued" anyway nowadays since the
inter-thread communication (from HTTP thread to your user thread) is happening
via the event loop. Also it is not queued until a new event will be handled, it
should flow to your user thread without further delay.
I have no idea right now why your issue could happen =>
https://bugreports.qt-project.org
bye,
Markus
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