comp.lang.ruby

Ken Bloom

12/20/2006 3:26:00 PM

On Wed, 20 Dec 2006 23:04:16 +0900, James Smith wrote:

> Hello,
>
> I am opening a file and reading from it. I need to leave the file and
> then return to the position that i finished reading at.
>
> OK, so i can get the exact position in bytes using pipe.pos
>
> However when i return to the file i then need to jump back to this
> position, i can't seem to so this using ios.seek, is there a way to do
> this?
>
> The final resort i suppose would be to write something to the file to
> mark the last position of reading and then when returning read and do
> nothing untill you hit this spot.. any other ideas?

Works just fine for me, although I had to seek to 0 to begin with for it
to work.:

irb(main):001:0> f=open("/dev/full","r")
=> #<File:/dev/full>
irb(main):002:0> f.read(120)
=> 120 null bytes
irb(main):003:0> f.pos
Errno::EINVAL: Invalid argument - /dev/full
from (irb):3:in `pos'
from (irb):3
from :0
irb(main):005:0> f.seek 400
=> 0
irb(main):006:0> f.pos
=> 400
irb(main):007:0> f.seek 0
=> 0
irb(main):008:0> f.read 120
=> 120 null bytes
irb(main):009:0> f.pos
=> 120


--
Ken Bloom. PhD candidate. Linguistic Cognition Laboratory.
Department of Computer Science. Illinois Institute of Technology.
http://www.iit.edu...