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Re: Restarting Curses

From: Tim Mooney
Subject: Re: Restarting Curses
Date: Thu, 3 Sep 2009 14:55:16 -0500 (CDT)

In regard to: Restarting Curses, Nicholas Cole said (at 3:30pm on Sep 3, 2009):

Dear Curses List,

I have a strange problem.  I have code that can start up and close
down curses making sure the terminal is reset.  But if I call it a
second time, the terminal is not properly reset.  I'm using python,
but I suspect it would be the same in C.  What might I be doing wrong?

It's been years and years since I've done any curses programming so I'm
a little rusty, but I do remember this hard-learned lesson: you only want
to call initscr() ONCE per program.

I'm sure others can correct me on this, but if you need to "shell out" of
your curses app for a while, you do want to call endwin().  When you're
ready to come back to your curses app, I believe just a
"refresh()/wrefresh()/doupdate()" will do what you need.  I used
refresh() and that worked perfectly for the curses-based menu system I was

PS: Looking at the source code for the curses-based app I worked on, it's
been 14 years since I last did any real curses programming, yet I still
remember the initscr() lesson.  ;-)


Python curses provides a wrapper function precisely for the purpose of
setting up the terminal and then resetting it, and the same behaviour
happens whether I use that or set up curses myself.

Minimal code looks something like:

#def wrapper(call_function):
#       locale.setlocale(locale.LC_ALL, '')
#       screen = curses.initscr()
#       curses.noecho()
#       curses.cbreak()
#       return_code = call_function(screen)
#       curses.nocbreak()
#       curses.echo()
#       curses.endwin()

As I say, it seems to work the first time it is called, but not the
second.  Any insights?

Tim Mooney                                  address@hidden
Enterprise Computing & Infrastructure       701-231-1076 (Voice)
Room 242-J6, IACC Building                  701-231-8541 (Fax)
North Dakota State University, Fargo, ND 58105-5164

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