noalias comments to X3J11

Sean Fagan sef at csun.UUCP
Tue Mar 29 00:55:20 AEST 1988


In article <588 at imagine.PAWL.RPI.EDU> beowulf!lunge!jesup at steinmetz.UUCP writes:
>In article <1988Mar25.172355.348 at utzoo.uucp> henry at utzoo.uucp (Henry Spencer) writes:
>>>>`Volatile,' in particular, is a frill for esoteric applications...
>>
>>Interrupt routines are almost by definition esoteric, not to mention highly
>>machine-specific.
>	'Volatile' is extremely important for dealing with real-world
>hardware.

Another use I haven't seen mentioned is for shared memory.  Since this can
be accessed (and modified) by more than one process, having a heavily
optimizing compiler move one location (or more) into a register would be a
bad idea.  Doing something like

	volatile char shm_seg[1024];
	shmat(...,shm_seg,...);

seems like it would be nice to have (I may have screwed up the syntax of the
shared memory stuff, pardon me).

>>"Noalias must go.  This is           |  Henry Spencer @ U of Toronto Zoology
>>non-negotiable."  --DMR              | {allegra,ihnp4,decvax,utai}!utzoo!henry
> ^^^^^^^^^^^^^^^^
>Now that we can agree on!
As has been stated before, when this man (dmr at alice) speaks, ANSI should
listen!

>     //	Randell Jesup			      Lunge Software Development
-- 

Sean Fagan                   uucp:   {ihnp4,hplabs,psivax}!csun!sef
CSUN Computer Center         BITNET: 1GTLSEF at CALSTATE
Northridge, CA 91330         (818) 885-2790



More information about the Comp.lang.c mailing list