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From: dylan@ibmpcug.co.uk (Matthew Farwell)
Newsgroups: comp.lang.c
Subject: Re: Novice question.
Message-ID: <1990Nov14.110638.5713@ibmpcug.co.uk>
Date: 14 Nov 90 11:06:38 GMT
References: <1990Oct31.014132.2400@agate.berkeley.edu> <336@brat.UUCP> <3838@vela.acs.oakland.edu> <1990Nov14.010511.7241@ux1.cso.uiuc.edu>
Reply-To: dylan@ibmpcug.CO.UK (Matthew Farwell)
Organization: The IBM PC User Group, UK.
Lines: 24

In article <1990Nov14.010511.7241@ux1.cso.uiuc.edu> gordon@osiris.cso.uiuc.edu (John Gordon) writes:
>jmwojtal@vela.acs.oakland.edu (Wojo) writes:
>>What exactly are the reasons "register" and "extrn" are used to declare
>>values.  I see register alot in some of the programs and I don't know why
>>they do it.  Is it just good practice or what.
>
>	"register" means that the variable will be stored in a portion of
                                           ^^^^
>memory that can be accessed significantly faster than normal.  Useful for 
>loop counters, among other things.  There are a limited number of registers
>available.  MS-DOS machines, for example, have around 16 (I think).

Surely this should be 'might be stored in a high speed register', depending
on whether the compiler wants to put it there, is able to put it there,
whether there is an s in the day today, etc. etc. I always thought that
register was just advice to the compiler, which its free to ignore if it
wants to or is unable to fulfil the request.

Dylan.
-- 
Matthew J Farwell                 | Email: dylan@ibmpcug.co.uk
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