Whither _noalias_?

[Erik Naggum]

I haven't been able to get ANSI X3.159-1989, yet, and I found a draft
dated 11 Jan 1988.  If my question does not apply to the approved
standard, that answers my question.

In the list of type qualifiers, along with the new const and volatile,
a _noalias_ type qualifier is introduced, with a description that I
have hard time just parsing.  The text goes as follows:

	If the noalias-qualified lvalues that contains a particular
	noalias-handle had instead had the non-noalias-qualified
	version of their types, the set of all objects accessible by
	these lvalues constitue the _actual_objects_ of the particular
	noalias handle.  ...

It's an understatement to say that I spent some time trying to
understand this passage, and the following.  The Rationale was almost,
but not quite, as helpful as the draft text.

I haven't seen any mention of "noalias" in ANSI C compilers I've
talked to, so I just wonder if I wasn't alone in not really grasping
what noalias was good for and why its introduction was required.

Can anybody shed some light on the fate of the "noalias" type
qualifier?

--
[Erik Naggum]	Snail: Naggum Software / BOX 1570 VIKA / 0118 OSLO / NORWAY
		Mail: <erik at naggum.uu.no>, <enag at ifi.uio.no>
My opinions.	Wail: +47-2-836-863	Another int'l standards dude.