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From: kenner@lab.ultra.nyu.edu (Richard Kenner)
Subject: Re: C's register keyword
Date: 1997/09/10
Message-ID: <5v4u97$nrg$1@news.nyu.edu>#1/1
X-Deja-AN: 271160805
References: <5uqhm2$t48$1@goanna.cs.rmit.edu.au> <34111A70.2158@online.no>
Organization: New York University Ultracomputer Research Lab
Newsgroups: comp.lang.ada
Date: 1997-09-10T00:00:00+00:00
List-Id: <comp.lang.ada>


In article <34111A70.2158@online.no> tarjei@online.no writes:
>If you think the register keyword is sacred in C, read the GCC manual.
>If my memory serves me right they say that they ignore it or strongly
>dissaprove of its use.

No.  The "register" keyword has precisely one semantic meaning in C, which
is to make it an error to take the address of an object with the keyword.
In other words, it is precisely the opposite of "aliased" in Ada.

GCC correctly implements this keyword.

It also has a historical aspect of suggestign which variables get placed
into registers.  Like all modern compilers, GCC ignores this purpose for
the keyword if optimizing, but does use it as a guide when not optimizing.