Why 'struct foo *x' instead of 'foo *x'

[Andrew Koenig]

In article <878 at m3.mfci.UUCP>, karzes at mfci.UUCP (Tom Karzes) writes:
> In article <9137 at csli.Stanford.EDU> jkl at csli.stanford.edu (John Kallen) writes:
> >
> >Does anybody know the reason why structs are defined as they are in C?
> >I.e. why do I have to say "struct foo" instead of just the tag "foo"?

> I think one reason is that it allows pointers to foo before foo itself is
> actually defined.  For example:

>     struct foo {
>         struct bar *pb;
>     };

>     struct bar {
>         struct foo *pf;
>     };

You can say `foo' instead of `struct foo' in C++.

It handles the forward reference problem in one of two ways.

One is to allow `struct foo' as a type name even if `foo' has
not yet been defined.  That makes the example above legal.

The other way is to allow the existence of a type name
to be established before the definition in some circumstances:

	struct bar;

	struct foo {
		bar *pb;
	};

	struct bar {
		foo *pf;
	};
-- 
				--Andrew Koenig
				  ark at europa.att.com