Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!purdue!decwrl!sun!pitstop!sundc!seismo!uunet!mcvax!hp4nl!philmds!leo
From: leo@philmds.UUCP (Leo de Wit)
Newsgroups: comp.lang.c
Subject: Re: incomplete types (was: Recursive #includes)
Message-ID: <976@philmds.UUCP>
Date: 13 Mar 89 19:16:08 GMT
References: <570@marob.MASA.COM> <9727@smoke.BRL.MIL> <964@philmds.UUCP> <3804@xyzzy.UUCP> <7488@june.cs.washington.edu> <9804@smoke.BRL.MIL> <1567@ubu.warwick.UUCP> <9842@smoke.BRL.MIL>
Reply-To: leo@philmds.UUCP (Leo de Wit)
Organization: Philips I&E DTS Eindhoven
Lines: 19

In article <9842@smoke.BRL.MIL> gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>) writes:
|There is nothing inherently "bad" about incomplete types, especially
|incomplete structure declarations.  In fact they are essential for
|declaring structures that contain pointers to each other.

How essential that is? Consider:

struct egg {
     struct hen {
          struct egg *eggp;
     } *henp;
};

This declares two structure types, each containing a pointer to the
other one. And I can give more complex examples (a nice one is the
grammar for the Bourne shell, which can be expressed in these type of
recursive data structures: essentially one big struct definition).

    Leo.