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Path: utzoo!utgpu!watserv1!watmath!att!rutgers!uwm.edu!spool!8099PIERZINA@vmsd.csd.mu.edu
From: 8099pierzina@vmsd.csd.mu.edu (Todd Pierzina)
Newsgroups: comp.lang.c,comp.os.vms
Subject: fseek in VAX C
Message-ID: <0093978E.33625920@vmsd.csd.mu.edu>
Date: 10 Jul 90 20:57:37 GMT
Sender: news@spool.mu.edu
Reply-To: 8099pierzina@vmsd.csd.mu.edu (Todd Pierzina)
Followup-To: comp.lang.c
Organization: Marquette University - Computer Services
Lines: 27

I need help.

I am using VAX C, and I want to move backward through a data (record, not
stream!) file.  I am trying to use fseek.  I have RTFMed, and it is very
ambiguous as far as fseek and record files go.  The Unix version would be

      (void) fseek(fp, (long)-sizeof(record_type), L_INCR);

where fp is the file pointer.  In VAX C, the RTL manual says that using fseek
with a value not obtained from ftell is very unpredictable.  No sh*t.

I could set up a stack of ftell values going forward, then when I need to go
back, pop the locations off and feed them to fseek directly.  I think.  So my
questions(s):

Is there an EASY way to move backward?

Will my stack method work?  I do not understand how fseek/ftell work with
record files; the manual is VERY confusing.

Please reply directly to me, as I am not subscribed to these lists.
Todd Pierzina

Student Programmer
Marquette University
8099PIER@MUCSD                (BITNET)
8099pierzina@vmsd.csd.mu.edu  (Internet)