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From: boyne@hplvli.HP.COM (Art Boyne)
Newsgroups: comp.lang.c
Subject: Re: Compilers and programming style (was Re: A question of style)
Message-ID: <340015@hplvli.HP.COM>
Date: 10 Jan 90 16:23:26 GMT
References: <564@mwtech.UUCP>
Organization: Loveland Inst. Div
Lines: 16

scott@bbxsda.UUCP (Scott Amspoker) writes:
>bright@dataio.Data-IO.COM (Walter Bright) writes:
>>volatile int *p;
>>*p;		/* has side effects and must not be optimized away	*/

>Just curious - what kind of code should be generated for the above
>C fragment?

Simple: a read of the address pointed to by |p|, of whatever # of bits
an int is defined as on your particular machine.

The C code I write is mostly firmware built into instruments, and I
have repeatedly used this construct to force a read of a hardware
register, eg., to clear/disable an interrupt or other condition.

Art Boyne, boyne@hplvla.hp.com