Path: utzoo!utgpu!news-server.csri.toronto.edu!clyde.concordia.ca!uunet!van-bc!rsoft!mindlink!a1040
From: a1040@mindlink.UUCP (Robert Broughton)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Random Access Files in C
Message-ID: <2714@mindlink.UUCP>
Date: 3 Aug 90 23:17:12 GMT
Organization: MIND LINK! - British Columbia, Canada
Lines: 22

> Peter_Warren_Lee@cup.portal.com writes:
> 
> >I'm just starting to play around with C and was browsing through a few
> >books to see what kinds of commands were in the language. I saw some file
> functions that appeared to be used for writing sequential files but I
> didn't see anything that would handle random access files. Is there a
> good way to do it in C?
> 
> If your records are fixed length, all you have to do is multiply the record
> length by the record number, and lseek() to that location. If your records
> are variable-length, store the first byte of each record in an array, read
> that array from the disk each time you open the file, and write it to disk
> when you close it.
> 
> If you want to do direct access using KEYS instead of "record numbers", buy a
> copy of dBC III from Lattice. It is a set of C-callable functions which
> process files in dBASE-style files and indexes.
> 
> Finally, a philosophical note; C doesn't include FORTRAN-style random-access
> for the same reason that it does not include a ** operator for
> exponentiation. C was designed to avoid hiding what the
> computer is actually doing from the programmer.