[Kde-bindings] Qyoto: Reading from stdin from a gui-application

[Arno Rehn]

Am Sonntag 18 Mai 2008 15:52:29 schrieb Christoph Spielmann:
> Arno Rehn schrieb:
> > Am Sonntag 18 Mai 2008 11:36:57 schrieb Christoph Spielmann:
> >> Hi everybody!
> >>
> >> I'm working on an application which receives commands from stdin. After
> >> a bit of googleing i found the following solution for doing that using
> >> qt (the original example code was not for qyoto but i assumed it would
> >>
> >> work similarly so i just adepted the code...):
> >> |...
> >>
> >> public QFile stdin;
> >> public QSocketNotifier stdinNot;
> >> ...
> >> this.stdin=new QFile();
> >> this.stdin.Open(0,(int) QIODevice.OpenModeFlag.ReadOnly); //open stdin
> >> for reading
> >>
> >> this.stdinNot=new QSocketNotifier(0,QSocketNotifier.TypeOf.Read);
> >> QObject.Connect(this.stdinNot,
> >> Qt.SIGNAL("activated(int)"),this,Qt.SLOT("DataReadyOnStdin()"));
> >>
> >> ...
> >> [Q_SLOT]
> >> public void DataReadyOnStdin() {
> >>     Console.WriteLine(this.stdin.Read("",255L));
> >> }
> >> ...
> >>
> >>
> >>
> >> i have to use both a QSocketNotifier and QFile to get notified as soon
> >> as we have acitvity on stdin, because according to the QT-documentation
> >> QFile does NOT emit the readyRead() signal (which is a shame in my eyes
> >> but okey, i could live with the above solution if it would work... ;) ).
> >>
> >> As soon as i enter something to stdin the activiated(int) signal gets
> >> emitted as expected but as soon as i actually try to read from stdin
> >> using the QFile-object stdin i get this:
> >>
> >> Cannot handle 'qint64' as argument to QIODevice::read
> >>
> >> So what is the correct way to read data from stdin within a
> >> qyoto-gui-application? I'm open for all suggestion as i am kinda out of
> >> ideas how to solve this task!
>
> Hi!
>
> > Actually it's much easier to simply use Console.Read() or
> > Console.ReadLine()
>
> Well yes they work but somehow they seem to block the main event loop
> and the ui is not usable any more. So that's not what i want.
>
> > from the System namespace, but it should also work with the Qt classes.
> > The error indicates that we currently don't handle qint64, which should
> > be quite easy to fix. I'll look into this.
>
> I tried out the fix you proposed and now the error message is gone but
> it's still not working as expected. If I use QTextStream as proposed by
> qt-documentation nothing happens (e.g when i use the Read*-methods of
> QTextStream) or i get a endless-loop if i use AtEnd() for example. When
> i use QFile directly using the Read*-methods i get very strange results:
>
> Read(string,long): nothing happens
> ReadLine(string,long): the method returns the correct length of bytes
> available but the string it's supposed to append the bytes to is not
> changed ReadAll(): nothing happens
>
> So i guess i found another problem... ;)
Strange. Have you tried to do it in C++ and does it work there? It would also 
be helpful if you sent the source of this, so we can test it.


-- 
Arno Rehn
arno at arnorehn.de