c++/3304: g++ accepts array definition with non-constant dimensions

c++/3304: g++ accepts array definition with non-constant dimensions

[jeggers]

>Number:         3304
>Category:       c++
>Synopsis:       g++ accepts array definition with non-constant dimensions
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    unassigned
>State:          open
>Class:          accepts-illegal
>Submitter-Id:   net
>Arrival-Date:   Wed Jun 20 13:16:01 PDT 2001
>Closed-Date:
>Last-Modified:
>Originator:     John Eggers
>Release:        GCC 2.96 20000731
>Organization:
>Environment:
Linux 7.0
>Description:
g++ accepts the following as correct, even with the -ansi
switch.

//***** Begin Code Fragment *****
   cout << "Enter the sum (a positive integer): ";
   cin >> sum;
   
   cout << "Enter the size (a positive integer): ";
   cin >> size;
   
   cout << endl;
   
   const int SIZE = size;
   const int SUM = sum;
   
   int Sum[SIZE+1][SUM+1];
//***** End Code Fragment *****

Note:  g++ also accepts

   int (*Sum)[SUM+1] = new int[SIZE+1][SUM+1];
>How-To-Repeat:
Compile attached file with g++.  Also, comment-out the line
   int Sum[SIZE+1][SUM+1];
and un-comment the line
   int (*Sum)[SUM+1] = new int[SIZE+1][SUM+1];
and then compile.
>Fix:
I do not have the expertise to suggest a fix, except to note
that the above code should be rejected by any ANSI-compliant
C++ compiler (although, I found it very convenient that g++
let me get away with the above code).
>Release-Note:
>Audit-Trail:
>Unformatted:
----gnatsweb-attachment----
Content-Type: application/octet-stream; name="test1.cpp"
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="test1.cpp"

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Re: c++/3304: g++ accepts array definition with non-constant dimensions

[gdr]

Synopsis: g++ accepts array definition with non-constant dimensions

Responsible-Changed-From-To: unassigned->gdr
Responsible-Changed-By: gdr
Responsible-Changed-When: Sat Aug 11 14:39:53 2001
Responsible-Changed-Why:
    Analyzed.
State-Changed-From-To: open->closed
State-Changed-By: gdr
State-Changed-When: Sat Aug 11 14:39:53 2001
State-Changed-Why:
    This is not a bug.  GCC emits a warning with -pedantic.
    
    -- Gaby

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view&pr=3304&database=gcc