Re: Display corruption with certain programs

[Thomas Dickey]

Date: Tue, 06 Aug 2013 11:57:24 +0200
> 
> Ever since switching to ncurses 5.9-dev some months ago I have been
> noticing the same display bugs in "my" applications which use it,
> htop and ncmpcpp. This happens on both my computers. See the
> screenshots:
> 
> http://imgur.com/a/1xTsU#0
> 
> The occurrence is not entirely consistent, sometimes htop will look
> fine directly after start. In ncmpcpp it almost always happens,
> especially after a few songs with the playlist open.
> 
> Manually selecting a line will "reset" it to proper display, letting
> the program display something else (eg another ncmpcpp menu - which
> will leave the status bar corrupted, as it's not switched) or
> changing console dimensions brings back the proper one, too.

The most likely reason is if a program was doing printf's mixed with curses 
calls.
To resolve a problem with signal handlers, ncurses doesn't buffer its output in
the same way.  The fix for those programs is to modify them to do fflush's 
before
calling ncurses(*)

(*) technically, there should be very few programs doing this, to solve some
    specific problem, in practice there are also programs doing this due to
    it usually "working", and not being noticed.  Mixing curses and printf's
    has never been advised nor supported.

-- 
Thomas E. Dickey <address@hidden>
http://invisible-island.net
ftp://invisible-island.net

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