How to print in a native format using Qprinter

Dear Friends,
I am trying to print text using Qprinter, it gives error like this,

lpr: Unsupported format 'application/postscript'!

then i tried with setoutputformat() member, still gives same error can any body help me please,

code is

Code:

QTextEdit *editor = static_cast<QTextEdit*>(letters->currentWidget());
//! [18]
    QPrinter printer;
    printer.setOutputFormat(QPrinter::NativeFormat);
    printer.setPrintProgram("lpr");
    QPrintDialog *dialog = new QPrintDialog(&printer, this);
    dialog->setWindowTitle(tr("Print Document"));
    dialog->
    if (editor->textCursor().hasSelection())
        dialog->addEnabledOption(QAbstractPrintDialog::PrintSelection);
    if (dialog->exec() != QDialog::Accepted)
        return;
//! [18]
    editor->print(&printer);