Re: c/5336: initializer element is not constant

Re: c/5336: initializer element is not constant

[rth]

Synopsis: initializer element is not constant

State-Changed-From-To: open->closed
State-Changed-By: rth
State-Changed-When: Mon Apr 29 18:25:50 2002
State-Changed-Why:
    Not a bug.  Constant data does not a constant expression make.
    See section 6.6 of the ISO C standard.  In part:
    
    An integer constant expression shall have integer type and shall only have operands
    that are integer constants, enumeration constants, character constants, sizeof
    expressions whose results are integer constants, and floating constants that are the
    immediate operands of casts. Cast operators in an integer constant expression shall only
    convert arithmetic types to integer types, except as part of an operand to the sizeof
    operator.

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=5336

Re: c/5336: initializer element is not constant

[Luben Tuikov]

The following reply was made to PR c/5336; it has been noted by GNATS.

From: Luben Tuikov <luben@splentec.com>
To: gcc-gnats@gcc.gnu.org, gcc-prs@gcc.gnu.org, dima@cc.hut.fi,
   gcc-bugs@gcc.gnu.org, nobody@gcc.gnu.org
Cc:  
Subject: Re: c/5336: initializer element is not constant
Date: Mon, 29 Apr 2002 16:37:05 -0400

 http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=5336
 
 I've reconfirmed this error on gcc 3.0.4/GNU/Linux 2.4.18/Red Hat 7.1.
 
 It is gcc's error!
 
 Here is my code:
 ---cut-----------------
 #include <stdio.h>
 
 typedef struct {
 	int i;
 	char c;
 } IC_t;
 
 const IC_t def_tic = { 'A', 'A' };
 
 static const int testme = sizeof(int) + def_tic.i;  /* gcc-gcc, where are you? */
 
 int main()
 {
 	def_tic.c = 'b';			    /* error ok */
 
 	/* threaten to use */
 	printf("def_tic.c = %c\n", def_tic.c);
 
 	return 0;
 }
 ---cut-----------------
 
 Furthermore, ``def_tic'' is put into the read-only
 section of the ELF, just as ``testme'' would be if
 it could compile it -- still gcc doesn't consider
 it and craps out.
 
 This is somewhat a severe bug, as it forces me to write
 ugly code (workarounds gcc's behavior).
 
 Please, please, fix it.
 
 -- 
 Luben

c/5336: initializer element is not constant

[dima]

>Number:         5336
>Category:       c
>Synopsis:       initializer element is not constant
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    unassigned
>State:          open
>Class:          rejects-legal
>Submitter-Id:   net
>Arrival-Date:   Wed Jan 09 08:36:01 PST 2002
>Closed-Date:
>Last-Modified:
>Originator:     dima@cc.hut.fi
>Release:        2.96 (*g*), 3.0.1
>Organization:
>Environment:

>Description:
compiler exits with error on code which is legal at least in common sense.



when comiling something like:



int * const ptr1 = (int *) 0xf0f0f0f0;

int * const ptr2 = ptr1;



compiler exits with error "initializer element is not constant", although it sorta is. it's not "a constant", but it sure is "constant".



I'll go dig C docs, if it is indeed so that init element must be "a constant expression" then a change of error message would be good.
>How-To-Repeat:
int * const ptr1 = (int *) 0xf0f0f0f0;

int * const ptr2 = ptr1;
>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted: