Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!uunet!mcsun!cernvax!roberto
From: roberto@cernvax.UUCP (roberto bagnara)
Newsgroups: gnu.gcc.bug
Subject: Possibly wrong warnings about passing const and volatile pointers
Keywords: const, volatile, warnings
Message-ID: <1220@cernvax.UUCP>
Date: 24 Jan 90 16:17:55 GMT
Organization: CERN, Geneva, Switzerland
Lines: 68


/*
**	Compiler:	GNU CC
**	Version:	1.36
**	System:		Motorola 3300 Delta Series running sysV68 R3.5
**	File:		const.c
**	Command:	gcc -c const.c
**	Problem:	Possibly wrong warnings about passing const
**			and volatile pointers
**	Reporter:	Roberto Bagnara, CS Department, PISA University
**
**	Discaimer:	I haven't the ANSI C specifications at hand.
*/

/* Try this to see what happens with volatile */
#if 0
#define const volatile
#endif

typedef int **ipp;
typedef const int **cipp;
typedef int * const *ipcp;
typedef const int * const *cipcp;

void fipp(ipp a);
void fcipp(cipp a);
void fipcp(ipcp a);
void fcipcp(cipcp a);


/* Wrong warning ==
	`warning: argument passing between incompatible pointer types'
   instead of
	`warning: argument passing of non-const * pointer from const *'
*/

/* Spurious warning ==
	`warning: argument passing between incompatible pointer types'
   given when there is nothing to complain
*/

main()
{
	ipp ippv;
	cipp cippv;
	ipcp ipcpv;
	cipcp cipcpv;

	fipp(ippv);	/* Legal */
	fipp(cippv);	/* Illegal */	/* Wrong warning */
	fipp(ipcpv);	/* Illegal */
	fipp(cipcpv);	/* Illegal */	/* Wrong warning */

	fcipp(ippv);	/* Legal */	/* Spurious warning */
	fcipp(cippv);	/* Legal */
	fcipp(ipcpv);	/* Illegal */	/* Wrong warning */
	fcipp(cipcpv);	/* Illegal */

	fipcp(ippv);	/* Legal */
	fipcp(cippv);	/* Illegal */	/* Wrong warning */
	fipcp(ipcpv);	/* Legal */
	fipcp(cipcpv);	/* Illegal */	/* Wrong warning */

	fcipcp(ippv);	/* Legal */	/* Spurious warning */
	fcipcp(cippv);	/* Legal */
	fcipcp(ipcpv);	/* Legal */	/* Spurious warning */
	fcipcp(cipcpv);	/* Legal */
}