QProcess and reading data from xterm

[sawerset]

I sarts xterm from my program by using QProcess.
I need to send to xterm "tty" command and reads its output.
I try to do it a such way

terminalProc.start("xterm");
	terminalProc.setReadChannel(QProcess::StandardOutput);
 
	terminalProc.waitForStarted(-1);
	terminalProc.write("tty\n");	
	QByteArray result = terminalProc.readAllStandardOutput();

terminalProc.start("xterm");
	terminalProc.setReadChannel(QProcess::StandardOutput);
	
	terminalProc.waitForStarted(-1);
	terminalProc.write("tty\n");	
	QByteArray result = terminalProc.readAllStandardOutput();

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But result is empty. What i am doing wrong?
Is there any other way to get value of tty?