why can't QProcess read all output?

[Raul]

In C you can use:

printf(...);
fflush(stdout);

printf(...);
fflush(stdout);

To copy to clipboard, switch view to plain text mode 

to flush the stdout buffer

if like the following ?
void mainWindow::iupdateTextEdit()
{
QByteArray newData=inprocess.readAllStandardOutput();
QString text=textEdit->toPlainText()+QString::fromLocal8Bit(newData);
textEdit->setPlainText(text);
fflush(stdout);
}