Union type conversions

[Chris Torek]

>In article <19845 at watmath.waterloo.edu> atbowler at watmath.waterloo.edu
>>(Alan T. Bowler [SDG]) writes:
>>... there is no guarantee that the compiler does not simply do the
>>equivalent of `#define union struct' ...

In article <3714 at ece-csc.UUCP> jnh at ece-csc.UUCP (Joseph Nathan Hall) writes:
>Sorry, you're just plain wrong here.  From page 140 of K&R, I quote:

... from the *de*scriptive part of the text, which says only that

>	"In effect, a union is a structure in which all members have
>	 OFFSET ZERO [emphasis added] ..."

The point of this quote is to warn users that writing on any one
element of a union *may* stomp any other element, not that it *must*
stomp other elements.  Alan Bowler is right; unions make few
guarantees.  On the other hand, a compiler that does not conserve
storage with union definitions is probably not worth using.
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain:	chris at mimsy.umd.edu	Path:	uunet!mimsy!chris