Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cornell!uw-beaver!grace.cs.washington.edu!jeffb
From: jeffb@grace.cs.washington.edu (Jeff Bowden)
Newsgroups: comp.lang.c++
Subject: A question of references
Summary: How do you declare a reference to a pointer to T?
Message-ID: <JEFFB.89May7132808@grace.cs.washington.edu>
Date: 7 May 89 20:28:08 GMT
Sender: news@beaver.cs.washington.edu
Distribution: comp
Organization: Ministry of Silly Walks
Lines: 63


Here's the deal.  I've got a function in C which I am translating to C++.
Here is an abstraction of what the current function does:

	T *foo[ROWS][COLS];

	/* ... */

	void bar(/* args... */)
	{
	  T **d = &foo[r][c];

	  /* Many uses of `d' all of the form ``(*d)'' */
        }

Obviously, `d' is crying out ``I'm really a reference!''.  Now, since c++ has
this nifty ability to specify references I would like to declare `d' as such
and change all instances of ``(*d)'' to ``d''.

Problem is, I can't figure out how to declare it.  Obviously (?) it should be
either
	T *&d = ...
or
	T &*d = ....

But which?  And how, in general, do you figure it out?  I think the relevant
part of Stroustrup starts on page 269.  To wit:

      ``Now imagine a declaration

		T D1

	where `T' is a type-specifier (like `int', etc.) and `D1' is a
	declarator.

	...

	If D1 has the form

		&D
	or

		& const D

	the type of the contained identifier is `... reference to T.' ''
				  ^^^^^^^^^^

This leads me to think that either order doesn't matter or that in all cases
the "&" has to be the first thing.  The former seems unlikely so my guess is
that

	T &*d = ...

is what I want.  Is my interpretation correct or is there some other place in
Stroustrup which is more explicit about how references should really be
declared.


I realize that I could just test the possibilities out with a compiler but it
seems as though this really ought to be clearly documented and I'd like to
know where.
--
Say "lah vee."