How to Port Q3Process::launch to Qt4 ?

[darshan.hardas]

While porting code from Qt3 to Qt4, I encounter the following problem.

I create Process object

QProcess m_Process = QProcess(this);

QProcess m_Process = QProcess(this);

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Now there is one statement which needs to be ported:

m_Process->launch(some_Argument);

m_Process->launch(some_Argument);

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I have used :

m_Process->execute(some_Argument);

m_Process->execute(some_Argument);

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I'm using this, but the process doesn't get launch.

[marcel]

Look at the QProcess documentation. There is an example there.
execute() is a static member so you don't need a QProcess instance.

[radhika.khandway]

Even I am searching an equivalent function to Q3Process::launch.
But i didn't got.
I am porting some code from Qt3 to Qt4.
The Qt3 code is as follows:
m_process = new QProcess(this);

connect(m_process, SIGNAL(processExited()),
this, SLOT(slotPsOutputCompleted()));

m_process->launch(Arg);

I have used finished(int, QProcess::ExitStatus) signal instead of processExited().
But couldn't port launch in Qt4.
Please guide me for the same.

[patrik08]

Even I am searching an equivalent function to Q3Process::launch.
But i didn't got.
I am porting some code from Qt3 to Qt4.
The Qt3 code is as follows:
m_process = new QProcess(this);

connect(m_process, SIGNAL(processExited()),
this, SLOT(slotPsOutputCompleted()));
m_process->launch(Arg);

Have you found the porting solution without qt3to4?

I found the same problem on convert postscript file to PNG image

QT3 code send and take all data to stdin stdout and never save item to file....

proc = new QProcess();
#if defined(Q_OS_WIN32)
	proc->addArgument( "gswin32c" );
#else
	proc->addArgument( "gs" );
#endif
	proc->addArgument( "-q" );
	proc->addArgument( "-dBATCH" );
	proc->addArgument( "-dNOPAUSE" );
	proc->addArgument( "-sDEVICE=pnggray" );
	proc->addArgument( "-sOutputFile=-" );
	proc->addArgument( "-" );
 
     writingStdout = true;
     /* send postscript code to console */
	if ( !proc->launch( psBarcode ) ) {
        /* error code */
    } else {
        readingStdout = true;
		while ( readingStdout ) {
			qApp->processEvents();
			if ( !proc->isRunning() )
				writingStdoutFinished();    /* read png data from  console ...  */
		}
    }

proc = new QProcess();
#if defined(Q_OS_WIN32)
	proc->addArgument( "gswin32c" );
#else
	proc->addArgument( "gs" );
#endif
	proc->addArgument( "-q" );
	proc->addArgument( "-dBATCH" );
	proc->addArgument( "-dNOPAUSE" );
	proc->addArgument( "-sDEVICE=pnggray" );
	proc->addArgument( "-sOutputFile=-" );
	proc->addArgument( "-" );
     
     writingStdout = true;
     /* send postscript code to console */
	if ( !proc->launch( psBarcode ) ) {
        /* error code */
    } else {
        readingStdout = true;
		while ( readingStdout ) {
			qApp->processEvents();
			if ( !proc->isRunning() )
				writingStdoutFinished();    /* read png data from  console ...  */
		}
    }

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qt4 code ...

QStringList cmd;
    cmd.append(ghosti);   /* Ghostscript  bin full path */
    cmd.append("-dBATCH");
    cmd.append("-dNOPAUSE");
    cmd.append("-sDEVICE=pnggray");
    cmd.append("-sOutputFile="+imageiosFileCache);   /* define out file */
    cmd.append("-q");
    cmd.append(stimeFileCache);   /* define in file postscript to transform */
    Barcode_Delete( bc );   /* remove barcode gnu */
    errprocess = false;
    procfinished=false;
    if (getGSVersion().size() < 4) {
        PaintError(tr("Install Ghostscript."));
        return;
    }
    const QString makepnggreycommand = cmd.join(" ");
    proc = new QProcess(this);
    connect(proc, SIGNAL(finished(int)),this, SLOT(SlotEndProcess(int)));
    proc->start(makepnggreycommand);

QStringList cmd;
    cmd.append(ghosti);   /* Ghostscript  bin full path */
    cmd.append("-dBATCH");
    cmd.append("-dNOPAUSE");
    cmd.append("-sDEVICE=pnggray");
    cmd.append("-sOutputFile="+imageiosFileCache);   /* define out file */
    cmd.append("-q");
    cmd.append(stimeFileCache);   /* define in file postscript to transform */
    Barcode_Delete( bc );   /* remove barcode gnu */
    errprocess = false;
    procfinished=false;
    if (getGSVersion().size() < 4) {
        PaintError(tr("Install Ghostscript."));
        return;
    }
    const QString makepnggreycommand = cmd.join(" ");
    proc = new QProcess(this);
    connect(proc, SIGNAL(finished(int)),this, SLOT(SlotEndProcess(int)));
    proc->start(makepnggreycommand);

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QT4 QProcess having .... doc "Processes have two predefined output channels: The standard output channel (stdout) supplies regular console output, and the standard error channel (stderr) ...."

also i suppose if a stdin chanel not exist on QT4 QProcess maybe is not possibel to send postscript code to a chanel... grep QTextStream on site doc QProcess qt4 return Null..
Or ist this mistake , work on qt4 postscript transform without file ?