From: James Edward Gray II <james@...>
Date: 2007-08-08T06:55:27+09:00
Subject: Re: Need Solaris Help

On Aug 7, 2007, at 4:23 PM, Daniel Berger wrote:

>
>
> On Aug 7, 2:10 pm, James Edward Gray II <ja...@grayproductions.net>
> wrote:
>> On Aug 7, 2007, at 3:04 PM, Daniel Berger wrote:
>>
>>> I think you're better off using this snippet that Greg Hurrell  
>>> showed
>>> you earlier this year instead of shelling out at all. I've  
>>> modified it
>>> to use the correct value of TIOCGWINSZ for Solaris:
>>
>>> TIOCGWINSZ = 21608
>>> buf = [0, 0, 0, 0].pack('SSSS')
>>> if $stdin.ioctl(TIOCGWINSZ, buf) >= 0
>>>   rows, cols, xpixels, ypixels = buf.unpack("SSSS")
>>>   p rows, cols, xpixels, ypixels
>>> else
>>>   puts "Unable to get window size"
>>> end
>>
>> Can you explain why you feel the above is "better?"
>
> Because the output is predictable and therefore more reliable. It also
> doesn't require forking off a new process.
>
> I've no idea if the output from 'stty -a' is the same from Solaris
> 2.5.1 through Solaris 10. Also, have you verified that shelling out to
> stty returns the output you expect on other platforms such as HP-UX or
> AIX?
>
> Mind you, this approach requires figuring out the appropriate value
> for TIOCGWINSZ for each platform (which probably doesn't change
> between releases), but that's easier than parsing stdout for each
> platform IMHO.

It's this magic number work that scares me.  In fact, the entire  
chunk of code above is pretty opaque to me.

On the flip size, I understand exactly what the stty code does and  
how it works.  If it someone complains that it's broken on HP-UX,  
AIX, or their POSIX-compliant toaster, we will add another branch in  
the if chain.

I don't see that as any more maintenance than finding the magic  
number and I know how to ask users to help me do the former.

Ronald parsed the output for Solaris with a single trivial Regexp, so  
that didn't feel like a significant hurdle to me.

In short, I'm comfortable with the stty approach.  So far I haven't  
seen it blow up in anyway that I feel we would escape using ioctl().

Thanks for the advice though.

James Edward Gray II