>Number:         16997
>Category:       standards
>Synopsis:       #define vfscanf __svfscanf considered harmful
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    standards-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu May 23 23:00:00 PDT 2002
>Closed-Date:
>Last-Modified:
>Originator:     Jason R Thorpe
>Release:        NetBSD 1.5ZC
>Organization:
Wasabi Systems, Inc.
>Environment:
	
	
System: NetBSD yeah-baby.shagadelic.org 1.5ZC NetBSD 1.5ZC (YEAH-BABY-XP) #8: Sat May 4 15:32:58 PDT 2002 thorpej@yeah-baby.shagadelic.org:/u1/netbsd/src/sys/arch/i386/compile/YEAH-BABY-XP i386
Architecture: i386
Machine: i386
>Description:
	NetBSD's <stdio.h> has the following block of code:

/*
 * This is a #define because the function is used internally and
 * (unlike vfscanf) the name __svfscanf is guaranteed not to collide
 * with a user function when _ANSI_SOURCE or _POSIX_SOURCE is defined.
 */      
#define  vfscanf        __svfscanf

	This presents a problem when building recent versions of
	GCC (3.1 or later).  What happens is that GCC builds a
	table of built-in attributes to automatically apply to
	certain functions.  vfscanf is one if these functions (being
	in ISO C99).

	The file that builds this table also happens to have included
	<stdio.h> at some point (either directly or indirectly through
	another header file).

	Because of the #define above, the built-in attribute table
	ends up applying a scanf format attribute to "__svfscanf"
	rather than "vfscanf".  This results in testsuite failures:

FAIL: gcc.dg/format/c99-scanf-3.c vfscanf (test for warnings, line 21)
FAIL: gcc.dg/format/c99-scanf-3.c vfscanf (test for warnings, line 21)
FAIL: gcc.dg/format/ext-6.c vfscanf (test for warnings, line 42)
FAIL: gcc.dg/format/ext-6.c vfscanf (test for warnings, line 42)

>How-To-Repeat:
	See above.

>Fix:
	Not entirely clear.  I suspect this is really a GCC problem
	(and I plan on bringing this up with them, as well), but I
	wanted to make a record of it here, as well.
>Release-Note:
>Audit-Trail:
>Unformatted: