Path: utzoo!mnetor!uunet!uvm-gen!cavrak
From: cavrak@uvm-gen.UUCP (Steve Cavrak)
Newsgroups: comp.lang.c
Subject: Question about use of enum in typedef and struct
Message-ID: <823@uvm-gen.UUCP>
Date: 29 Apr 88 15:47:49 GMT
Organization: EMBA Computer Facility, Univ. of Vermont, Burlington.
Lines: 51
Keywords: enum, typedef, struct, syntax

Can someone explain why the following uses (abuses?) of typdef and enum
create problems in the struct that follows them?  (The example is taked
from a once working program that was being ported to a new compiler that
is "now ANSI" compliant.  The code has been "tested" on VAX BSD 4.3, VAX
VMS, and Turbo-C.  The "new" compiler is Waterloo C 3.0.)  The available
C documentation is not enlightening.  I'm sure that my Pascal mindset
adds to the confusion.

/*  Imnotok.c								*/
/*  Confusion using enumerated types in structures			*/
/*									*/
/*  The "_ok" declaration is usable in the struct definition AND	*/
/*  the "_to" declaration is usable, BUT				*/
/*  the "_no" declaration generates a syntax error.			*/
/*									*/
/*  Why?								*/
/*  ------------------------------------------------------------------  */
 
typedef int s_state_ok;					/*  OK		*/
typedef enum s_state_ok {
	initial_ok, middle_ok, final_ok
	};
 
typedef int s_state_to;					/*  OK		*/
enum s_state_to {
	initial_to, middle_to, final_to
	};
 
typedef enum s_state_no  {				/*  NOT OK	*/
	initial_no, middle_no, final_no
	};
 
struct	{
	int m;
	int n;
	s_state_ok s;		/* s_state_ok works, s_state_no fails 	*/
	} machine_state;
 
 
main ()
{
}

----------------------------------------------------------------
  _______
||       | Stephen J. Cavrak, Jr.               BITNET:  sjc@uvmvm
 |*     |					CSNET :  cavrak@uvm
 |     /   Academic Computing Services          USENET:  cavrak@uvm-gen
 |    |    University of Vermont
 |   |     Burlington, Vermont 05405
 ----