Path: utzoo!attcan!uunet!lll-winken!lll-tis!helios.ee.lbl.gov!pasteur!agate!labrea!decwrl!megatest!djones
From: djones@megatest.UUCP (Dave Jones)
Newsgroups: comp.lang.c
Subject: Re: register variable declaration question
Message-ID: <981@goofy.megatest.UUCP>
Date: 8 Nov 88 21:40:50 GMT
References: <624@scotty.UUCP>
Organization: Megatest Corporation, San Jose, Ca
Lines: 36

From article <624@scotty.UUCP>, by jwr@scotty.UUCP (Dier Retlaw Semaj):
> 
> A question:
> 
> When should one declare a parameter to be a register variable?
> 

I can't tell you when you "should" declare a register parameter,
but I can give you an example of how I use them.

I write lot's of C routines which are in the "object-oriented" mold.
That is to say, they update only one kind of data-structure.
I name the structures ("classes", in the current jargon) with typenames
with capital letters.  If a routine-name begins with a capitol letter,
the reader knows theat it is tied to a class -- it is a "method"
of that class.  It's first parameter, named "obj",  will invariably be 
a pointer to a structure of the given type.  I usually declare that pointer
to be "register", because it will be dereferenced many times within
the procedure.

typedef struct
{
  type1 field1;
  type2 field2;
  /* etc. */
}Widget;


int
Widget_fiddle(obj, arg1, arg2)
   register Widget* obj;
   int arg1;
   int arg2;
{
  /* Fiddle with the widget. */

}