Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!apple!ames!think!husc6!yale!mfci!karzes
From: karzes@mfci.UUCP (Tom Karzes)
Newsgroups: comp.lang.c
Subject: Re: Why 'struct foo *x' instead of 'foo *x'
Message-ID: <878@m3.mfci.UUCP>
Date: 28 May 89 19:06:03 GMT
References: <26575@watmath.waterloo.edu> <10213@claris.com> <9137@csli.Stanford.EDU>
Sender: karzes@mfci.UUCP
Reply-To: karzes@mfci.UUCP (Tom Karzes)
Organization: Multiflow Computer Inc., Branford Ct. 06405
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In article <9137@csli.Stanford.EDU> jkl@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;
    };

If you tried to say "bar *pb;" before bar was defined, you'd get an error.
(Note that although C is willing to assume the same machine representation
for all structure pointers, this is not true for arbitrary types (e.g.,
char *, int *, etc.)