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

[Christoph Spielmann]

Arno Rehn schrieb:
> Am Sonntag 18 Mai 2008 16:14:39 schrieb Arno Rehn:
>   
>> Am Sonntag 18 Mai 2008 15:52:29 schrieb Christoph Spielmann:
>>     
>>> 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
>>>       
> This is because these read methods expect a char*, that means a reference to a 
> string in which the data is stored. In Qyoto the code is wrongly generated, 
> so it won't work.
>
>   
>>> ReadAll(): nothing happens 
>>>       
> works for me.
>
>   
>>> 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.
>>     
Okey i wrote a short testapplication that should demonstrate what i want 
to accomplish. I wrote it in both c++ and c#.

hello-qt4.h

#include <QWidget>
#include <QFile>
#include <QSocketNotifier>

class MyWidget : public QWidget
{

        Q_OBJECT

        public:
                MyWidget(QWidget *parent = 0);
        public slots:
                void MyClose();
                void DataReadyOnStdin();
        private:
                QFile* stdin;
                QSocketNotifier* stdinNot;
};

hello-qt4.cpp:

#include <QApplication>
#include <QPushButton>
#include <stdio.h>
#include "hello-qt4.h"


 MyWidget::MyWidget(QWidget *parent)
     : QWidget(parent)
 {
     setFixedSize(200, 120);

     QPushButton *quit = new QPushButton(tr("Quit"), this);
     quit->setGeometry(62, 40, 75, 30);
     quit->setFont(QFont("Times", 18, QFont::Bold));

     connect(quit, SIGNAL(clicked()), this, SLOT(MyClose()));

     stdin=new QFile();
     stdin->open(0,QIODevice::ReadOnly);

     stdinNot=new QSocketNotifier(0,QSocketNotifier::Read);
     connect(stdinNot,SIGNAL(activated(int)),this,SLOT(DataReadyOnStdin()));
 }

 void MyWidget::MyClose() {
    printf("hello world closing!\n");
    exit(0);
 }

 void MyWidget::DataReadyOnStdin() {
    char* buf=(char*)malloc(255*sizeof(char));
    stdin->readLine(buf,(qint64)sizeof(buf));
    printf("%s\n",buf);
    free(buf);
 }


int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    MyWidget widget;
    widget.show();

    //connect(quit, SIGNAL(clicked()), widget, SLOT(MyClose()));

    /*QPushButton hello("Hello world!");
    hello.resize(100, 30);

    QObject::connect(&hello, SIGNAL(clicked()), &app, SLOT(quit()));

    hello.show();*/
    return app.exec();
 }

This implementation is doing exactly what i want. And now the same thing 
in C#:

using System;
using Qyoto;

namespace qttest1
{
    class MyWidget:QWidget
    {
        private QFile stdin;
        private QSocketNotifier stdinNot;
        public MyWidget():base() {
            this.SetFixedSize(200, 120);
            QPushButton quit=new QPushButton("Quit",this);
            quit.SetGeometry(62, 40, 75, 30);
            QObject.Connect(quit, Qt.SIGNAL("clicked()"), qApp, 
Qt.SLOT("quit()"));
            this.stdin=new QFile();
            this.stdin.Open(0,(int) QIODevice.OpenModeFlag.ReadOnly);

            this.stdinNot=new 
QSocketNotifier(0,QSocketNotifier.TypeOf.Read);
            
QObject.Connect(stdinNot,Qt.SIGNAL("activated(int)"),this,Qt.SLOT("DataReadyOnStdin()"));
        }
       
        [Q_SLOT]
        public void DataReadyOnStdin() {
            string buf="";
            this.stdin.ReadLine(buf,(long)255);
            Console.WriteLine(buf);
        }
        public static int Main(string[] args)
        {
            new QApplication(args);
            MyWidget widget=new MyWidget();
            widget.Show();
            return QApplication.Exec();
        }
    }
}

Here everything works except reading from stdin (means 
this.stdin.ReadLine(buf,(long)255);). When i try to replace ReadLine 
with ReadAll the UI becomes unresponsive and that should not happen in 
my application.

Some more info on my setup:

I'm on Gentoo/AMD64 (i can almost here the oh-noes here ;) ) here, with 
QT 4.3.4 (qt-4.4 has not hit portage yet) and kde-4.0.4 with manually 
compiled kdebindings (another thing that's not in the tree, quite a 
shame in my eyes but okey i can help myself ;) )

So well i hope anyone can make sense of all this and help me out.

Christoph
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