bugGNU Octave - Bugs: bug #32240, \b doesn't work when followed...

 
 

bug #32240: \b doesn't work when followed directly by \n

Submitted by:  Jeremy Trammell <novalis112>
Submitted on:  Tue 25 Jan 2011 05:53:31 AM UTC  
 
Category: InterpreterSeverity: 3 - Normal
Priority: 5 - NormalItem Group: Incorrect Result
Status: InvalidAssigned to: None
Originator Name: Jeremy TrammellOpen/Closed: Closed
Release: 3.2.4Operating System: Microsoft Windows

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Tue 25 Jan 2011 09:05:07 AM UTC, comment #4:

My previous comment did not post correctly.

I intended to say:

If by

you mean that when you type backspace on the command line, the previous character is deleted, then that is happening because the readline library that handles command line input has complete control over what appears on the screen. The printf function is only sending characters to an output stream. It has no control over what happens after that.

John W. Eaton <jwe>
Project Administrator
Tue 25 Jan 2011 08:57:36 AM UTC, comment #3:

Then the place to fix it is in the terminal, not Octave. Octave is sending the backspace to the terminal. It is the terminal's job to decide what to do about that, not Octave.

If by

John W. Eaton <jwe>
Project Administrator
Tue 25 Jan 2011 08:41:50 AM UTC, comment #2:

Suit yourself, but I spent a good half an hour banging my head on a wall because that was not the behavior I expected. In the command line interpreter backspace seems to be destructive, not non-destructive. I think it's natural to assume that printf would behave similarly... At the very least, I would update the documentation to make it clear that for the purposes of printf, \b is a non-destructive backspace.

Jeremy Trammell <novalis112>
Tue 25 Jan 2011 08:31:57 AM UTC, comment #1:

As far as I can tell, Octave is sending the sequence of characters

to the terminal.

I think the reason the I doesn't disappear when it is followed by backspace and linefeed is that neither of these are printing characters, so they don't overwrite the previous character. When you follow the backspace character by another printing character, it overwrites the I. This all looks like the expected behavior to me, so I'm closing this report as invalid.

John W. Eaton <jwe>
Project Administrator
Tue 25 Jan 2011 05:53:31 AM UTC, original submission:
Jeremy Trammell <novalis112>

 

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    Follow 5 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Tue 25 Jan 2011 09:05:07 AM UTCjweSummary\\b doesn\'t work when followed directly by \\n=>\b doesn't work when followed directly by \n
    Tue 25 Jan 2011 08:57:36 AM UTCjweSummary\\b doesn\'t work when followed directly by \\n=>\b doesn't work when followed directly by \n
    Tue 25 Jan 2011 08:31:57 AM UTCjweStatusNone=>Invalid
      Open/ClosedOpen=>Closed
      Summary\\b doesn\'t work when followed directly by \\n=>\b doesn't work when followed directly by \n

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