Qt-interest Archive, March 2007
QT and POSIX Threads
Message 1 in thread
Hi,
I have a main program which creates two threads.
In the first thread, i have created the GUI which has a log window.
In the other thread, i m running some application, i want to redirect the
output of the applciation (the output is continuous) to GUI log window
which is in other thread.
I am not using QThreads and i am using pthread_create to create threads.
Can i acheive this using some QEvents?
I thought of redirecting the output from applciation thread to Global
Variable and i dont know how to invoke an event in the GUI thread if that
global variable is set.
Can anyone help me?
Best Regards,
Hemanth
=====-----=====-----=====
Notice: The information contained in this e-mail
message and/or attachments to it may contain
confidential or privileged information. If you are
not the intended recipient, any dissemination, use,
review, distribution, printing or copying of the
information contained in this e-mail message
and/or attachments to it are strictly prohibited. If
you have received this communication in error,
please notify us by reply e-mail or telephone and
immediately and permanently delete the message
and any attachments. Thank you
Message 2 in thread
On Wednesday 14 March 2007 10:23, Hemanth N wrote:
> Hi,
>
> I have a main program which creates two threads.
>
> In the first thread, i have created the GUI which has a log window.
First, be sure to read
http://doc.trolltech.com/4.2/threads.html#threads-and-qobjects, because:
"Although QObject is reentrant, the GUI classes, notably QWidget and all its
subclasses, are not reentrant. They can only be used from the main thread. As
noted earlier, QCoreApplication::exec() must also be called from that
thread."
Be sure to create your GUI and call exec() in the main() thread.
> In the other thread, i m running some application, i want to redirect the
> output of the applciation (the output is continuous) to GUI log window
> which is in other thread.
>
> I am not using QThreads and i am using pthread_create to create threads.
>
> Can i acheive this using some QEvents?
>
> I thought of redirecting the output from applciation thread to Global
> Variable and i dont know how to invoke an event in the GUI thread if that
> global variable is set.
You can use QApplication::postEvent() to post events to the GUI. These events
will be handled in the main() thread. You can put all of the data you need
into a QEvent subclass, which also eliminates the need for global
variables ;)
--
[ signature omitted ]
