libstdc++/5110: num_put caches num_punct values

libstdc++/5110: num_put caches num_punct values

[sebor]

>Number:         5110
>Category:       libstdc++
>Synopsis:       num_put caches num_punct values
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Dec 13 18:56:00 PST 2001
>Closed-Date:
>Last-Modified:
>Originator:     sebor@roguewave.com
>Release:        gcc 3.0.1
>Organization:
>Environment:

>Description:
The program below produces unexpected output and fails
with non-0 exit status. The expected output is 

123+456+78+9-1-234-567-89-123/456/789

and the expected exit status is 0. My guess is that it's
because num_put is caching the values supplied by numpunct,
which I don't believe is permitted in Stage 2 in 22.2.2.2.2.

Regards
Martin
>How-To-Repeat:
$ cat t.cpp
#include <iostream>
#include <locale>

int main ()
{
    struct Punct: std::numpunct<char> {
        string_type do_grouping () const {
            static const char *grp = "\1\2\3";
            return grp++;
        }

        char_type do_thousands_sep () const {
            static const char *sep = "+-/";
            return *sep++;
        }
    };


    std::locale l (std::cout.getloc (), (std::numpunct<char>*)new Punct);
    std::cout.imbue (l);

    std::cout << 123456789 << -123456789 << -123456789 << std::endl;

    return *std::use_facet<std::numpunct<char> >(std::cout.getloc ()).grouping (
).c_str ();
}

$ g++ t.cpp
$ ./a.out ; echo $?
123+456+78+9-123+456+78+9-123+456+78+9
2
>Fix:

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

Re: libstdc++/5110: num_put caches num_punct values

[rodrigc]

Synopsis: num_put caches num_punct values

State-Changed-From-To: feedback->closed
State-Changed-By: rodrigc
State-Changed-When: Sun Mar  3 11:16:29 2002
State-Changed-Why:
    Output of gcc 3.0.4:
    123+456+78+9-123+456+78+9-123+456+78+9
    
    Output of 20020217 (experimental):
    123+456+78+9-1-234-567-89-/123/456/789

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=5110

Re: libstdc++/5110: num_put caches num_punct values

[Martin Sebor]

The following reply was made to PR libstdc++/5110; it has been noted by GNATS.

From: Martin Sebor <sebor@roguewave.com>
To: gcc-gnats@gcc.gnu.org, gcc-bugs@gcc.gnu.org
Cc:  
Subject: Re: libstdc++/5110: num_put caches num_punct values
Date: Fri, 04 Jan 2002 16:27:48 -0700

 http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=5110
 
 It turns out that the caching of values returned from facet virtuals
 is not only meant to be allowed, but it was even specifically intended
 when locale was designed. I will be submitting an issue to clarify the
 standard to that effect. The opinion of the rest of the LWG is that
 behavior of the test case should be unspecified.
 
 Thanks
 Martin

Re: libstdc++/5110: num_put caches num_punct values

[paolo]

The following reply was made to PR libstdc++/5110; it has been noted by GNATS.

From: paolo@gcc.gnu.org
To: gcc-bugs@gcc.gnu.org, gcc-gnats@gcc.gnu.org, gcc-prs@gcc.gnu.org,
  nobody@gcc.gnu.org, sebor@roguewave.com
Cc:  
Subject: Re: libstdc++/5110: num_put caches num_punct values
Date: 14 Dec 2001 07:46:30 -0000

 Synopsis: num_put caches num_punct values
 
 State-Changed-From-To: open->feedback
 State-Changed-By: paolo
 State-Changed-When: Thu Dec 13 23:46:29 2001
 State-Changed-Why:
     The problem is confirmed in the branch (3.0.2), but I
     cannot reproduce it with current 3.1 experimental snapshots.
     
     paolo:~> g++ sebor.cc
     paolo:~> a.out
     123+456+78+9-1-234-567-89-/123/456/789
     paolo:~> g++ --verbose
     Reading specs from /usr/local/gcc-temp/lib/gcc-lib/i686-pc-linux-gnu/3.1/specs
     Configured with: ../Sandbox2/gcc/configure --prefix=/usr/local/gcc-temp --enable-languages=c,c++
     Thread model: single
     gcc version 3.1 20011212 (experimental)
     
     Could you perhaps test one of those?
     
     Thanks,
     Paolo.
 
 http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&pr=5110&database=gcc

Re: libstdc++/5110: num_put caches num_punct values

[paolo]

Synopsis: num_put caches num_punct values

State-Changed-From-To: open->feedback
State-Changed-By: paolo
State-Changed-When: Thu Dec 13 23:46:29 2001
State-Changed-Why:
    The problem is confirmed in the branch (3.0.2), but I
    cannot reproduce it with current 3.1 experimental snapshots.
    
    paolo:~> g++ sebor.cc
    paolo:~> a.out
    123+456+78+9-1-234-567-89-/123/456/789
    paolo:~> g++ --verbose
    Reading specs from /usr/local/gcc-temp/lib/gcc-lib/i686-pc-linux-gnu/3.1/specs
    Configured with: ../Sandbox2/gcc/configure --prefix=/usr/local/gcc-temp --enable-languages=c,c++
    Thread model: single
    gcc version 3.1 20011212 (experimental)
    
    Could you perhaps test one of those?
    
    Thanks,
    Paolo.

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&pr=5110&database=gcc