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[Caml-list] no tell on files?
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Date: 2003-02-05 (08:43)
From: Ed L Cashin <ecashin@u...>
Subject: Re: [Caml-list] no tell on files?
Chris Hecker <checker@d6.com> writes:

> There appears to be no "tell" function on pervasives streams or Unix
> file descriptors.  Is there a reason for this?  The combination of
> that plus the lack of a pervasives relative seek makes it hard to move
> around in files without keeping parallel information.

Seek is tell!  The program below gives this output:

  ecashin@meili seek-tell$ ./a.out 
  read 10 chars: " Unix.SEEK"

let main = 
  let fd = Unix.openfile "main.ml" [Unix.O_RDONLY] 0 in
  let end_pos = Unix.lseek fd 0 Unix.SEEK_END in
  let half_pos = Unix.lseek fd (end_pos/2) Unix.SEEK_SET and
      buf = String.create 1024 in
  Printf.printf "read %d chars: \"%s\"\n"
    (UnixLabels.read fd ~buf ~pos:0 ~len:10)


--Ed L Cashin            |   PGP public key:
  ecashin@uga.edu        |   http://noserose.net/e/pgp/
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