Re: [TCLCORE] TIP #206: Add an [ftruncate] Command

[Donal K. F. <don...@ma...>]

Tom Krehbiel wrote:
> I'm not a deep thinker like Don, but I did wonder what the truncate 
> command accomplish that isn't provided by seek. My understanding is that 
> moving the current access position to a new location in the file will 
> cause the file to be truncated when it is closed.

I hate to do this, but you're wrong. My evidence is the following log
from a tclsh session (on WinXP, but I think all tclsh instances behave
the same way):
   % set f [open wibble.txt w]
   fileb01950
   % puts $f "foobar"
   % close $f
   % type wibble.txt
   foobar
   % set f [open wibble.txt r+]
   fileb0e648
   % seek $f 3
   % puts $f ""
   % close $f
   % type wibble.txt
   foo
   r

Donal.