Path: utzoo!utgpu!watserv1!watmath!att!dptg!ulysses!andante!alice!ark
From: ark@alice.UUCP (Andrew Koenig)
Newsgroups: comp.lang.c++
Subject: Re: const
Message-ID: <11300@alice.UUCP>
Date: 6 Sep 90 18:04:44 GMT
References: <10863@cadillac.CAD.MCC.COM> <27503@pasteur.Berkeley.EDU>
Organization: AT&T Bell Laboratories, Liberty Corner NJ
Lines: 32

In article <27503@pasteur.Berkeley.EDU>, twagner@baobab.berkeley.edu (Tim Wagner) writes:

> This points out once again the problems inherent in C's (and therefore C++'s)
> use of 'const'.  The return type of the function is not a good mechanism
> in this case: obviously, one cannot really alter the returned value anyhow,
> so calling it 'const' is redundant.  However, the context in which that
> returned value is used should be controlled; that is, an lvalue getting
> such a returned object should be const itself.

Not at all!  If you assign the result of a function to a variable,
the variable gets a copy of that result.  Just because the result
itself is a constant, that doesn't say anything about the copy.

For example:

	int x = 3;

Here, 3 is a `const int,' but that surely does not oblige x to be
a const!   Similarly:

	extern const int f();

	main()
	{
		int x = f();
		// ...
	}

Again, there is no particular reason why x should have to be a const.
-- 
				--Andrew Koenig
				  ark@europa.att.com