From: "B. K. Oxley (binkley)" <binkley@...>
Date: 2005-04-27T04:47:17+09:00
Subject: Re: Clearing StringIO

Ara.T.Howard@noaa.gov wrote:
> [ahoward@localhost ~]$ env PAGER=cat man truncate | grep pointer
>        The file pointer is not changed.

This is highly system-dependent (although I am unable to tell if the 
behavior has standardized over time):

http://www.faqs.org/faqs/unix-faq/faq/part3/section-3.html

<<
For systems which support the ftruncate function, there are
       three known behaviours:

       BSD 4.2 - Ultrix, SGI, LynxOS
               - truncation doesn't grow file
               - truncation doesn't move file pointer


       BSD 4.3 - SunOS, Solaris, OSF/1, HP/UX, Amiga
               - truncation can grow file
               - truncation doesn't move file pointer

       Cray    - UniCOS 7, UniCOS 8
               - truncation doesn't grow file
               - truncation changes file pointer
 >>


Cheers,
--binkley