[Bug c/15444] New: Bad warning message in printf format checking

[Bug c/15444] New: Bad warning message in printf format checking

[james-gcc-bugzilla-501qll3d at and dot org]

Although gcc can check i18n parameter specifiers in printf format strings, the
warning given if you mix them is the confusing 'warning: unknown conversion type
character `$' in format'. Admitedly SuSv3 does say...

The format can contain either numbered argument conversion specifications (that
is, "%n$" and "*m$"), or unnumbered argument conversion specifications (that is,
% and * ), but not both.

...however glibc does work in this mode, as do a number of other implementations
of printf.

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           Summary: Bad warning message in printf format checking
           Product: gcc
           Version: 3.3.2
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P2
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: james-gcc-bugzilla-501qll3d at and dot org
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15444

[Bug c/15444] Bad warning message in printf format checking

[james-gcc-bugzilla-501qll3d at and dot org]

------- Additional Comments From james-gcc-bugzilla-501qll3d at and dot org  2004-05-14 18:08 -------
Created an attachment (id=6292)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=6292&action=view)
test case compile with "gcc -Wall -W -o gcc-bug gcc-bug.c"


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15444

[Bug c/15444] Bad warning message in printf format checking

[jsm at polyomino dot org dot uk]

------- Additional Comments From jsm at polyomino dot org dot uk  2004-05-14 18:18 -------
Subject: Re:  New: Bad warning message in printf format checking

On Fri, 14 May 2004, james-gcc-bugzilla-501qll3d at and dot org wrote:

> The format can contain either numbered argument conversion specifications (that
> is, "%n$" and "*m$"), or unnumbered argument conversion specifications (that is,
> % and * ), but not both.
> 
> ...however glibc does work in this mode, as do a number of other implementations
> of printf.

This must be some strange meaning of "work" - far from documenting any
meaning for which argument an unnumbered specifier takes if there are also
numbered ones (next from the start, or from the previous numbered one?),
the glibc manual expressly repeats that it is undefined:

# If any of the formats has a specification for the parameter position all
# of them in the format string shall have one.  Otherwise the behavior is
# undefined.

The diagnostics could however be improved to check for $ argument numbers
when it is known they must not appear and give a more specific diagnostic.



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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15444

[Bug c/15444] Bad warning message in printf format checking

[james-gcc-bugzilla-501qll3d at and dot org]

------- Additional Comments From james-gcc-bugzilla-501qll3d at and dot org  2004-05-14 18:38 -------
 Yes, the main point was that the message should be different.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15444

[Bug c/15444] Bad warning message in printf format checking

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |diagnostic


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15444

[Bug c/15444] Bad warning message in printf format checking

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2004-05-15 00:44 -------
Subject: Bug 15444

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	jsm28@gcc.gnu.org	2004-05-15 00:44:03

Modified files:
	gcc            : ChangeLog c-format.c 
	gcc/testsuite  : ChangeLog 
	gcc/testsuite/gcc.dg/format: xopen-1.c 
Added files:
	gcc/testsuite/gcc.dg/format: xopen-3.c 

Log message:
	PR c/15444
	* c-format.c (avoid_dollar_number): New function.
	(check_format_info_main): Call avoid_dollar_number when operand
	numbers might occur but has_operand_number == 0.
	
	testsuite:
	* gcc.dg/format/xopen-1.c: Adjust expected message.
	* gcc.dg/format/xopen-3.c: New test.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&r1=2.3659&r2=2.3660
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/c-format.c.diff?cvsroot=gcc&r1=1.54&r2=1.55
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/ChangeLog.diff?cvsroot=gcc&r1=1.3748&r2=1.3749
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gcc.dg/format/xopen-3.c.diff?cvsroot=gcc&r1=NONE&r2=1.1
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/gcc.dg/format/xopen-1.c.diff?cvsroot=gcc&r1=1.3&r2=1.4



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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15444

[Bug c/15444] Bad warning message in printf format checking

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-05-15 00:46 -------
Fixed for 3.5.0.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |3.5.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15444