Best way of finding terminal width/height?

[Joel Hedlund]

Thank you for a very quick, informative and concise response.

> BTW: don't forget to attach a handler to the window-size-change
> signal (SIGWINCH) so that you know when your terminal changes sizes

Do you mean something like this?

import signal, os
# terminal_info contains the example from my first post
from terminal_info import get_terminal_size

TERMINAL_SIZE = get_terminal_size()

def update_terminal_size(signum, frame):
    global TERMINAL_SIZE
    TERMINAL_SIZE = get_terminal_size()

signal.signal(signal.SIGWINCH, update_terminal_size)

while True:
    # Do lots of IO (fishing for exceptions...)
    open('/a/large/file').read()
    print TERMINAL_SIZE

The docs for the signal module (http://docs.python.org/lib/module-signal.html) say that 
"""
When a signal arrives during an I/O operation, it is possible that the I/O operation raises an exception after the signal handler returns. This is dependent on the underlying Unix system's semantics regarding interrupted system calls.

"""
So this is what I'm trying to provoke in the final while loop. In this case I get no exceptions (hooray!). However, if I replace open('/a/large/file').read() with raw_input() I get EOFError (no errmsg), and even worse, if I replace it with sys.stdin.read() or even print open('/a/large/file').read() I get IOError: [Errno 4] Interrupted system call.

I do lots of IO in my work, and primarily with gigantic text files (welcome to bioinformatics :-). Protecting my code from this sort of error (i believe) will be quite hard, and probably won't look pretty. Or am I missing something?

Note though that these realtime updates aren't essential to me at the moment. Basically all I need is to find out for each run how much space I have so I can text wrap command line help text (as in myprog --help) as user friendly as possible. 

I run Ubuntu 5.10 btw, but I try to stay as cross-platform as I can. My priorities are Ubuntu, other linuxes, other unixes, Win, Mac.

> Homey don't do Windows, so you'll have to ask somebody else that.

:-)

> I don't know what you mean by "leverage the termios module".
>
>>I have a hunch that we have 100% overlap there,
> 
> No comprende.

I mean: I believe that for those environments where $COLS and $ROWS are set
then python will probably have access to the termios module as well, and for those environments that don't have $COLS and $ROWS set then python probably will not have access to the termios module either. So, in the latter case I'm back to square one, which is arbitrary guesswork.

>  1) Just write a normal Unix-like text processing "filter". 

Yes that's what I normally do. But I also like to hook them up with a --help option that shows usage and options and such, and I like that warm fuzzy feeling you get from seeing really readable user friendly help... :-)

> I would guess that the real answer is that so few people have
> ever wanted it that nobody has ever created a module and
> submitted it.  Feel free...  ;) 

I just might. I've got some stuff that people may benefit from (or possibly hate, I don't know ;-). If I ever sum up the courage to publish it, would it be a good idea to post the modules to python-dev at python.org, or is there some better route?

Thanks again for your time!
/Joel