Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!lll-winken!uunet!modcomp!joe
From: joe@modcomp.UUCP
Newsgroups: comp.lang.c
Subject: Re: foo = *((bar *)stuff)
Message-ID: <90700002@modcomp>
Date: 2 May 89 17:52:00 GMT
References: <712@tekno.chalmers.se>
Lines: 22
Nf-ID: #R:tekno.chalmers.se:712:modcomp:90700002:000:855
Nf-From: modcomp.UUCP!joe    May  2 13:52:00 1989


yair@tybalt.caltech.edu writes:
>Sven (Sciz) Axelsson writes:
>>Isn't this code supposed to assign the integer value contained
>>at memory position 10 to the variable x?
>>
>>	x = *((int *)10);
>>
>(int *) 10 should convert the integer 10 to a pointer, then the *
>should dereference the pointer, which on most (*not* all) machines
>should read location 10 of memory.  Note that this is extremely
>nonportable and very machine (even compiler) dependent.  [...] On 80x86
>machines this can cause problems since 'far' pointers may be different
>from 'near' pointers, ...

One (word-oriented) machine I've worked on had pointers of different
types with different internal representations.  A (char *)10 would reference
the 10'th *byte* of memory and a (int *)10 the 10'th *word* of memory.
Clearly, a very nonportable construct!

joe korty
uunet!modcomp!joe