Patchwork [2/9] Add __vfscanf_internal and __vfwscanf_internal with flags arguments.

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Submitter Zack Weinberg
Date March 7, 2018, 7:31 p.m.
Message ID <20180307193205.4751-3-zackw@panix.com>
Download mbox | patch
Permalink /patch/26231/
State New
Headers show

Comments

Zack Weinberg - March 7, 2018, 7:31 p.m.
There are two flags currently defined: SCANF_LDBL_IS_DBL is the mode
used by __nldbl_ scanf variants, and SCANF_ISOC99_A is the mode used
by __isoc99_ scanf variants.  In this patch, the new functions honor
these flag bits if they're set, but they still also look at the
corresponding bits of environmental state, and callers all pass zero.

The new functions do *not* have the "errp" argument possessed by
_IO_vfscanf and _IO_vfwscanf.  All internal callers passed NULL for
that argument.  External callers could theoretically exist, so I
preserved wrappers, but they are flagged as compat symbols and they
don't preserve the three-way distinction among types of errors that
was formerly exposed.  These functions probably should have been in
the list of deprecated _IO_ symbols in 2.27 NEWS -- they're not just
aliases for vfscanf and vfwscanf.

(It was necessary to introduce ldbl_compat_symbol for _IO_vfscanf.
Please check that part of the patch very carefully, I am still not
confident I understand all of the details of ldbl-opt.)

This patch also introduces helper inlines in libio/strfile.h that
encapsulate the process of initializing an _IO_strfile object for
reading.  This allows us to call __vfscanf_internal directly from
sscanf, and __vfwscanf_internal directly from swscanf, without
duplicating the initialization code.  (Previously, they called their
v-counterparts, but that won't work if we want to control *both* C99
mode and ldbl-is-dbl mode using the flags argument to__vfscanf_internal.)
It's still a little awkward, especially for wide strfiles, but it's
much better than what we had.

	* libio/libioP.h (SCANF_LDBL_IS_DBL, SCANF_ISOC99_A): New constants.
	(__vfscanf_internal, __vfwscanf_internal): New function prototypes.
        * libio/libio.h: Remove libc_hidden_proto for _IO_vfscanf.
	* libio/strfile.h: Add multiple inclusion guard.
	(_IO_strfile_read, _IO_strfile_readw): New inline functions.

	* sysdeps/generic/math_ldbl_opt.h: Include shlib-compat.h, for
	consistency with the other version of this file.
	(ldbl_compat_symbol): New macro.
	* sysdeps/ieee754/ldbl-opt/math_ldbl_opt.h (ldbl_compat_symbol):
	New macro.

	* stdio-common/vfscanf-internal.c: Rename from vfscanf.c.
	Define __vfscanf_internal or __vfwscanf_internal, depending on
	COMPILE_WPRINTF; don't define any other public symbols.
	Temporarily check __ldbl_is_dbl and _IO_FLAGS2_SCANF_STD as well
	as the mode_flags argument.
	(encode_error, conv_error, input_error): Don't set errval.
	* stdio-common/vfwscanf-internal.c: Rename from vfwscanf.c.
	Include vfscanf-internal.c.
	* stdio-common/vfscanf.c, stdio-common/vfwscanf.c: New files
	defining the public entry points vfscanf and vfwscanf respectively.
	* stdio-common/iovfscanf.c, stdio-common/iovfwscanf.c: New files
	defining the compat symbols _IO_vfscanf and _IO_vfwscanf respectively.
	* stdio-common/Makefile (routines): Add vfscanf-internal,
	vfwscanf-internal, iovfscanf, iovfwscanf.
        * stdio-common/Versions: Mention GLIBC_2.28, so that
        it can be used in SHLIB_COMPAT expressions.
	* sysdeps/ieee754/ldbl-opt/nldbl-compat.c (__nldbl__IO_vfscanf):
	Wrap definition and compat_symbol line in #if SHLIB_COMPAT.

	* libio/iovsscanf.c, libio/vscanf.c, libio/vwscanf.c, libio/wscanf.c
	* libio/iovswscanf.c, stdio-common/isoc99_fscanf.c
	* stdio-common/isoc99_scanf.c, stdio-common/isoc99_vfscanf.c
	* stdio-common/isoc99_vscanf.c, stdio-common/isoc99_vsscanf.c
	* stdio-common/scanf.c, sysdeps/ieee754/ldbl-opt/nldbl-compat.c
	* wcsmbs/isoc99_fwscanf.c, wcsmbs/isoc99_vfwscanf.c
	* wcsmbs/isoc99_vswscanf.c, wcsmbs/isoc99_vwscanf.c
	* wcsmbs/isoc99_wscanf.c: Use __vfscanf_internal instead of
	_IO_vfscanf, and/or __vfwscanf_internal instead of _IO_vfwscanf.

	* libio/iovsscanf.c, stdio-common/isoc99_vsscanf.c:
	Use _IO_strfile_read.  Clean up includes.
	* stdio-common/sscanf.c, stdio-common/isoc99_sscanf.c:
	Use _IO_strfile_read to set up a FILE, and then call
	__vfwcanf_internal directly.  Clean up includes.

	* libio/iovswscanf.c, wcsmbs/isoc99_vswscanf.c:
	Use _IO_strfile_readw.  Clean up includes.
	* libio/swscanf.c, wcsmbs/isoc99_swscanf.c:
	Use _IO_strfile_readw to set up a FILE, and then call
	__vfwscanf_internal directly.  Clean up includes.
---
 libio/iovsscanf.c                                |   12 +-
 libio/iovswscanf.c                               |   14 +-
 libio/libio.h                                    |    1 -
 libio/libioP.h                                   |    9 +
 libio/strfile.h                                  |   33 +-
 libio/swscanf.c                                  |   10 +-
 libio/vscanf.c                                   |    2 +-
 libio/vwscanf.c                                  |    2 +-
 libio/wscanf.c                                   |    2 +-
 stdio-common/Makefile                            |    3 +-
 stdio-common/Versions                            |    3 +
 stdio-common/iovfscanf.c                         |   34 +
 stdio-common/iovfwscanf.c                        |   34 +
 stdio-common/isoc99_fscanf.c                     |    2 +-
 stdio-common/isoc99_scanf.c                      |    2 +-
 stdio-common/isoc99_sscanf.c                     |    8 +-
 stdio-common/isoc99_vfscanf.c                    |    2 +-
 stdio-common/isoc99_vscanf.c                     |    2 +-
 stdio-common/isoc99_vsscanf.c                    |   17 +-
 stdio-common/scanf.c                             |    2 +-
 stdio-common/sscanf.c                            |   12 +-
 stdio-common/{vfscanf.c => vfscanf-internal.c}   |   46 +-
 stdio-common/vfscanf.c                           |   27 +
 stdio-common/{vfwscanf.c => vfwscanf-internal.c} |    2 +-
 stdio-common/vfwscanf.c                          |   25 +
 sysdeps/generic/math_ldbl_opt.h                  |    4 +
 sysdeps/ieee754/ldbl-opt/math_ldbl_opt.h         |    4 +
 sysdeps/ieee754/ldbl-opt/nldbl-compat.c          |   12 +-
 wcsmbs/isoc99_fwscanf.c                          |    2 +-
 wcsmbs/isoc99_swscanf.c                          |   12 +-
 wcsmbs/isoc99_vfwscanf.c                         |    2 +-
 wcsmbs/isoc99_vswscanf.c                         |   16 +-
 wcsmbs/isoc99_vwscanf.c                          |    2 +-
 wcsmbs/isoc99_wscanf.c                           |    2 +-
 34 files changed, 211 insertions(+), 115 deletions(-)
 create mode 100644 stdio-common/iovfscanf.c
 create mode 100644 stdio-common/iovfwscanf.c
 create mode 100644 stdio-common/vfscanf.c
 create mode 100644 stdio-common/vfwscanf.c
Adhemerval Zanella Netto - March 13, 2018, 12:35 p.m.
On 07/03/2018 16:31, Zack Weinberg wrote:
> There are two flags currently defined: SCANF_LDBL_IS_DBL is the mode
> used by __nldbl_ scanf variants, and SCANF_ISOC99_A is the mode used
> by __isoc99_ scanf variants.  In this patch, the new functions honor
> these flag bits if they're set, but they still also look at the
> corresponding bits of environmental state, and callers all pass zero.
> 
> The new functions do *not* have the "errp" argument possessed by
> _IO_vfscanf and _IO_vfwscanf.  All internal callers passed NULL for
> that argument.  External callers could theoretically exist, so I
> preserved wrappers, but they are flagged as compat symbols and they
> don't preserve the three-way distinction among types of errors that
> was formerly exposed.  These functions probably should have been in
> the list of deprecated _IO_ symbols in 2.27 NEWS -- they're not just
> aliases for vfscanf and vfwscanf.
> 
> (It was necessary to introduce ldbl_compat_symbol for _IO_vfscanf.
> Please check that part of the patch very carefully, I am still not
> confident I understand all of the details of ldbl-opt.)
> 
> This patch also introduces helper inlines in libio/strfile.h that
> encapsulate the process of initializing an _IO_strfile object for
> reading.  This allows us to call __vfscanf_internal directly from
> sscanf, and __vfwscanf_internal directly from swscanf, without
> duplicating the initialization code.  (Previously, they called their
> v-counterparts, but that won't work if we want to control *both* C99
> mode and ldbl-is-dbl mode using the flags argument to__vfscanf_internal.)
> It's still a little awkward, especially for wide strfiles, but it's
> much better than what we had.

Look good in general, some remarks below.

> 
> 	* libio/libioP.h (SCANF_LDBL_IS_DBL, SCANF_ISOC99_A): New constants.
> 	(__vfscanf_internal, __vfwscanf_internal): New function prototypes.
>         * libio/libio.h: Remove libc_hidden_proto for _IO_vfscanf.
> 	* libio/strfile.h: Add multiple inclusion guard.
> 	(_IO_strfile_read, _IO_strfile_readw): New inline functions.
> 
> 	* sysdeps/generic/math_ldbl_opt.h: Include shlib-compat.h, for
> 	consistency with the other version of this file.
> 	(ldbl_compat_symbol): New macro.
> 	* sysdeps/ieee754/ldbl-opt/math_ldbl_opt.h (ldbl_compat_symbol):
> 	New macro.
> 
> 	* stdio-common/vfscanf-internal.c: Rename from vfscanf.c.
> 	Define __vfscanf_internal or __vfwscanf_internal, depending on
> 	COMPILE_WPRINTF; don't define any other public symbols.
> 	Temporarily check __ldbl_is_dbl and _IO_FLAGS2_SCANF_STD as well
> 	as the mode_flags argument.
> 	(encode_error, conv_error, input_error): Don't set errval.
> 	* stdio-common/vfwscanf-internal.c: Rename from vfwscanf.c.
> 	Include vfscanf-internal.c.
> 	* stdio-common/vfscanf.c, stdio-common/vfwscanf.c: New files
> 	defining the public entry points vfscanf and vfwscanf respectively.
> 	* stdio-common/iovfscanf.c, stdio-common/iovfwscanf.c: New files
> 	defining the compat symbols _IO_vfscanf and _IO_vfwscanf respectively.
> 	* stdio-common/Makefile (routines): Add vfscanf-internal,
> 	vfwscanf-internal, iovfscanf, iovfwscanf.
>         * stdio-common/Versions: Mention GLIBC_2.28, so that
>         it can be used in SHLIB_COMPAT expressions.
> 	* sysdeps/ieee754/ldbl-opt/nldbl-compat.c (__nldbl__IO_vfscanf):
> 	Wrap definition and compat_symbol line in #if SHLIB_COMPAT.
> 
> 	* libio/iovsscanf.c, libio/vscanf.c, libio/vwscanf.c, libio/wscanf.c
> 	* libio/iovswscanf.c, stdio-common/isoc99_fscanf.c
> 	* stdio-common/isoc99_scanf.c, stdio-common/isoc99_vfscanf.c
> 	* stdio-common/isoc99_vscanf.c, stdio-common/isoc99_vsscanf.c
> 	* stdio-common/scanf.c, sysdeps/ieee754/ldbl-opt/nldbl-compat.c
> 	* wcsmbs/isoc99_fwscanf.c, wcsmbs/isoc99_vfwscanf.c
> 	* wcsmbs/isoc99_vswscanf.c, wcsmbs/isoc99_vwscanf.c
> 	* wcsmbs/isoc99_wscanf.c: Use __vfscanf_internal instead of
> 	_IO_vfscanf, and/or __vfwscanf_internal instead of _IO_vfwscanf.
> 
> 	* libio/iovsscanf.c, stdio-common/isoc99_vsscanf.c:
> 	Use _IO_strfile_read.  Clean up includes.
> 	* stdio-common/sscanf.c, stdio-common/isoc99_sscanf.c:
> 	Use _IO_strfile_read to set up a FILE, and then call
> 	__vfwcanf_internal directly.  Clean up includes.
> 
> 	* libio/iovswscanf.c, wcsmbs/isoc99_vswscanf.c:
> 	Use _IO_strfile_readw.  Clean up includes.
> 	* libio/swscanf.c, wcsmbs/isoc99_swscanf.c:
> 	Use _IO_strfile_readw to set up a FILE, and then call
> 	__vfwscanf_internal directly.  Clean up includes.
> ---
>  libio/iovsscanf.c                                |   12 +-
>  libio/iovswscanf.c                               |   14 +-
>  libio/libio.h                                    |    1 -
>  libio/libioP.h                                   |    9 +
>  libio/strfile.h                                  |   33 +-
>  libio/swscanf.c                                  |   10 +-
>  libio/vscanf.c                                   |    2 +-
>  libio/vwscanf.c                                  |    2 +-
>  libio/wscanf.c                                   |    2 +-
>  stdio-common/Makefile                            |    3 +-
>  stdio-common/Versions                            |    3 +
>  stdio-common/iovfscanf.c                         |   34 +
>  stdio-common/iovfwscanf.c                        |   34 +
>  stdio-common/isoc99_fscanf.c                     |    2 +-
>  stdio-common/isoc99_scanf.c                      |    2 +-
>  stdio-common/isoc99_sscanf.c                     |    8 +-
>  stdio-common/isoc99_vfscanf.c                    |    2 +-
>  stdio-common/isoc99_vscanf.c                     |    2 +-
>  stdio-common/isoc99_vsscanf.c                    |   17 +-
>  stdio-common/scanf.c                             |    2 +-
>  stdio-common/sscanf.c                            |   12 +-
>  stdio-common/{vfscanf.c => vfscanf-internal.c}   |   46 +-
>  stdio-common/vfscanf.c                           |   27 +
>  stdio-common/{vfwscanf.c => vfwscanf-internal.c} |    2 +-
>  stdio-common/vfwscanf.c                          |   25 +
>  sysdeps/generic/math_ldbl_opt.h                  |    4 +
>  sysdeps/ieee754/ldbl-opt/math_ldbl_opt.h         |    4 +
>  sysdeps/ieee754/ldbl-opt/nldbl-compat.c          |   12 +-
>  wcsmbs/isoc99_fwscanf.c                          |    2 +-
>  wcsmbs/isoc99_swscanf.c                          |   12 +-
>  wcsmbs/isoc99_vfwscanf.c                         |    2 +-
>  wcsmbs/isoc99_vswscanf.c                         |   16 +-
>  wcsmbs/isoc99_vwscanf.c                          |    2 +-
>  wcsmbs/isoc99_wscanf.c                           |    2 +-
>  34 files changed, 211 insertions(+), 115 deletions(-)
>  create mode 100644 stdio-common/iovfscanf.c
>  create mode 100644 stdio-common/iovfwscanf.c
>  create mode 100644 stdio-common/vfscanf.c
>  create mode 100644 stdio-common/vfwscanf.c
> 
> diff --git a/libio/iovsscanf.c b/libio/iovsscanf.c
> index e56ab8bd7d..ee6a99ec6a 100644
> --- a/libio/iovsscanf.c
> +++ b/libio/iovsscanf.c
> @@ -24,22 +24,14 @@
>     This exception applies to code released by its copyright holders
>     in files containing the exception.  */
>  
> -#include "libioP.h"
>  #include "strfile.h"
>  
>  int
>  _IO_vsscanf (const char *string, const char *format, va_list args)
>  {
> -  int ret;
>    _IO_strfile sf;
> -#ifdef _IO_MTSAFE_IO
> -  sf._sbf._f._lock = NULL;
> -#endif
> -  _IO_no_init (&sf._sbf._f, _IO_USER_LOCK, -1, NULL, NULL);
> -  _IO_JUMPS (&sf._sbf) = &_IO_str_jumps;
> -  _IO_str_init_static_internal (&sf, (char*)string, 0, NULL);
> -  ret = _IO_vfscanf (&sf._sbf._f, format, args, NULL);
> -  return ret;
> +  FILE *f = _IO_strfile_read (&sf, string);
> +  return __vfscanf_internal (f, format, args, 0);
>  }
>  ldbl_weak_alias (_IO_vsscanf, __vsscanf)
>  ldbl_weak_alias (_IO_vsscanf, vsscanf)

Ok.

> diff --git a/libio/iovswscanf.c b/libio/iovswscanf.c
> index 5bd1c88412..cb9cbe15cc 100644
> --- a/libio/iovswscanf.c
> +++ b/libio/iovswscanf.c
> @@ -24,24 +24,16 @@
>     This exception applies to code released by its copyright holders
>     in files containing the exception.  */
>  
> -#include "libioP.h"
> -#include "strfile.h"
>  #include <wchar.h>
> +#include "strfile.h"
>  
>  int
>  __vswscanf (const wchar_t *string, const wchar_t *format, va_list args)
>  {
> -  int ret;
>    _IO_strfile sf;
>    struct _IO_wide_data wd;
> -#ifdef _IO_MTSAFE_IO
> -  sf._sbf._f._lock = NULL;
> -#endif
> -  _IO_no_init (&sf._sbf._f, _IO_USER_LOCK, 0, &wd, &_IO_wstr_jumps);
> -  _IO_fwide (&sf._sbf._f, 1);
> -  _IO_wstr_init_static (&sf._sbf._f, (wchar_t *)string, 0, NULL);
> -  ret = _IO_vfwscanf ((FILE *) &sf._sbf, format, args, NULL);
> -  return ret;
> +  FILE *f = _IO_strfile_readw (&sf, &wd, string);
> +  return __vfwscanf_internal (f, format, args, 0);
>  }
>  libc_hidden_def (__vswscanf)
>  ldbl_hidden_def (__vswscanf, vswscanf)

Ok.

> diff --git a/libio/libio.h b/libio/libio.h
> index 00f9169613..d4eba2df54 100644
> --- a/libio/libio.h
> +++ b/libio/libio.h
> @@ -321,7 +321,6 @@ libc_hidden_proto (_IO_padn)
>  libc_hidden_proto (_IO_putc)
>  libc_hidden_proto (_IO_sgetn)
>  libc_hidden_proto (_IO_vfprintf)
> -libc_hidden_proto (_IO_vfscanf)
>  
>  #ifdef _IO_MTSAFE_IO
>  # undef _IO_peekc

Ok.

> diff --git a/libio/libioP.h b/libio/libioP.h
> index 8afe7032e3..a471c90be8 100644
> --- a/libio/libioP.h
> +++ b/libio/libioP.h
> @@ -704,6 +704,15 @@ extern off64_t _IO_seekpos_unlocked (FILE *, off64_t, int)
>  
>  #endif /* _G_HAVE_MMAP */
>  
> +/* Flags for __vfscanf_internal and __vfwscanf_internal.  */
> +#define SCANF_LDBL_IS_DBL 0x0001
> +#define SCANF_ISOC99_A    0x0002
> +
> +extern int __vfscanf_internal (FILE *fp, const char *format, va_list argp,
> +                               unsigned int flags);
> +extern int __vfwscanf_internal (FILE *fp, const wchar_t *format, va_list argp,
> +                                unsigned int flags);
> +
>  extern int _IO_vscanf (const char *, va_list) __THROW;
>  
>  #ifdef _IO_MTSAFE_IO

Ok.

> diff --git a/libio/strfile.h b/libio/strfile.h
> index 46ac81809a..715149f5bd 100644
> --- a/libio/strfile.h
> +++ b/libio/strfile.h
> @@ -24,7 +24,9 @@
>     This exception applies to code released by its copyright holders
>     in files containing the exception.  */
>  
> -#include <stdio.h>
> +#ifndef STRFILE_H_
> +#define STRFILE_H_
> +
>  #include "libioP.h"
>  
>  typedef void *(*_IO_alloc_type) (size_t);
> @@ -81,3 +83,32 @@ typedef struct
>  } _IO_wstrnfile;
>  
>  extern const struct _IO_jump_t _IO_wstrn_jumps attribute_hidden;
> +
> +/* Initialize an _IO_strfile SF to read from narrow string STRING, and
> +   return the corresponding FILE object.  It is not necessary to fclose
> +   the FILE when it is no longer needed.  */
> +static inline FILE *
> +_IO_strfile_read (_IO_strfile *sf, const char *string)
> +{
> +  sf->_sbf._f._lock = NULL;
> +  _IO_no_init (&sf->_sbf._f, _IO_USER_LOCK, -1, NULL, NULL);
> +  _IO_JUMPS (&sf->_sbf) = &_IO_str_jumps;
> +  _IO_str_init_static_internal (sf, (char*)string, 0, NULL);
> +  return &sf->_sbf._f;
> +}

Should we add a note about _IO_MTSAFE_IO cleanup?

> +
> +/* Initialize an _IO_strfile SF and _IO_wide_data WD to read from wide
> +   string STRING, and return the corresponding FILE object.  It is not
> +   necessary to fclose the FILE when it is no longer needed.  */
> +static inline FILE *
> +_IO_strfile_readw (_IO_strfile *sf, struct _IO_wide_data *wd,
> +                   const wchar_t *string)
> +{
> +  sf->_sbf._f._lock = NULL;
> +  _IO_no_init (&sf->_sbf._f, _IO_USER_LOCK, 0, wd, &_IO_wstr_jumps);
> +  _IO_fwide (&sf->_sbf._f, 1);
> +  _IO_wstr_init_static (&sf->_sbf._f, (wchar_t *)string, 0, NULL);
> +  return &sf->_sbf._f;
> +}
> +
> +#endif /* strfile.h.  */

Ok.

> diff --git a/libio/swscanf.c b/libio/swscanf.c
> index c8686bcbaf..90f721cc51 100644
> --- a/libio/swscanf.c
> +++ b/libio/swscanf.c
> @@ -15,20 +15,22 @@
>     License along with the GNU C Library; if not, see
>     <http://www.gnu.org/licenses/>.  */
>  
> -#include <libioP.h>
>  #include <stdarg.h>
> -#include <wchar.h>
> +#include "strfile.h"
>  
>  /* Read formatted input from S, according to the format string FORMAT.  */
> -/* VARARGS2 */
> +
>  int
>  __swscanf (const wchar_t *s, const wchar_t *format, ...)
>  {
>    va_list arg;
>    int done;
> +  _IO_strfile sf;
> +  struct _IO_wide_data wd;
> +  FILE *f = _IO_strfile_readw (&sf, &wd, s);
>  
>    va_start (arg, format);
> -  done = __vswscanf (s, format, arg);
> +  done = __vfwscanf_internal (f, format, arg, 0);
>    va_end (arg);
>  
>    return done;

Ok.

> diff --git a/libio/vscanf.c b/libio/vscanf.c
> index 9c27122c27..a3e2dd43f2 100644
> --- a/libio/vscanf.c
> +++ b/libio/vscanf.c
> @@ -32,6 +32,6 @@
>  int
>  _IO_vscanf (const char *format, va_list args)
>  {
> -  return _IO_vfscanf (_IO_stdin, format, args, NULL);
> +  return __vfscanf_internal (_IO_stdin, format, args, 0);
>  }
>  ldbl_weak_alias (_IO_vscanf, vscanf)

Ok.

> diff --git a/libio/vwscanf.c b/libio/vwscanf.c
> index 0d5f558758..7af770c8c3 100644
> --- a/libio/vwscanf.c
> +++ b/libio/vwscanf.c
> @@ -30,6 +30,6 @@
>  int
>  __vwscanf (const wchar_t *format, va_list args)
>  {
> -  return _IO_vfwscanf (_IO_stdin, format, args, NULL);
> +  return __vfwscanf_internal (_IO_stdin, format, args, 0);
>  }
>  ldbl_strong_alias (__vwscanf, vwscanf)

Ok.

> diff --git a/libio/wscanf.c b/libio/wscanf.c
> index c8cdad0acd..fe27ff6fa6 100644
> --- a/libio/wscanf.c
> +++ b/libio/wscanf.c
> @@ -30,7 +30,7 @@ __wscanf (const wchar_t *format, ...)
>    int done;
>  
>    va_start (arg, format);
> -  done = _IO_vfwscanf (stdin, format, arg, NULL);
> +  done = __vfwscanf_internal (stdin, format, arg, 0);
>    va_end (arg);
>  
>    return done;

Ok.

> diff --git a/stdio-common/Makefile b/stdio-common/Makefile
> index 9dfc115313..b7b1f01bdd 100644
> --- a/stdio-common/Makefile
> +++ b/stdio-common/Makefile
> @@ -39,7 +39,8 @@ routines	:=							      \
>  	flockfile ftrylockfile funlockfile				      \
>  	isoc99_scanf isoc99_vscanf isoc99_fscanf isoc99_vfscanf isoc99_sscanf \
>  	isoc99_vsscanf							      \
> -	psiginfo gentempfd
> +	psiginfo gentempfd						      \
> +	vfscanf-internal vfwscanf-internal iovfscanf iovfwscanf
>  
>  aux	:= errlist siglist printf-parsemb printf-parsewc fxprintf
>  

Ok.

> diff --git a/stdio-common/Versions b/stdio-common/Versions
> index 5016f69c20..7af44949f7 100644
> --- a/stdio-common/Versions
> +++ b/stdio-common/Versions
> @@ -57,6 +57,9 @@ libc {
>      psiginfo;
>      register_printf_modifier; register_printf_type; register_printf_specifier;
>    }
> +  GLIBC_2.28 {
> +    # SHLIB_COMPAT(GLIBC_2_0, GLIBC_2_28) used in iovfscanf.c etc
> +  }



>    GLIBC_PRIVATE {
>      # global variables
>      _itoa_lower_digits;
> diff --git a/stdio-common/iovfscanf.c b/stdio-common/iovfscanf.c
> new file mode 100644
> index 0000000000..fb347d60cb
> --- /dev/null
> +++ b/stdio-common/iovfscanf.c
> @@ -0,0 +1,34 @@
> +/* Copyright (C) 1991-2018 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.

Missing one line description.

> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <http://www.gnu.org/licenses/>.  */
> +
> +#include <libioP.h>
> +#include <shlib-compat.h>
> +
> +#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_28)
> +
> +int
> +attribute_compat_text_section
> +__IO_vfscanf (FILE *fp, const char *format, va_list ap, int *errp)
> +{
> +  int rv = __vfscanf_internal (fp, format, ap, 0);
> +  if (__glibc_unlikely (errp != 0))
> +    *errp = (rv == -1);
> +  return rv;
> +}
> +ldbl_compat_symbol (libc, __IO_vfscanf, _IO_vfscanf, GLIBC_2_0);
> +
> +#endif
> diff --git a/stdio-common/iovfwscanf.c b/stdio-common/iovfwscanf.c
> new file mode 100644
> index 0000000000..73936f68b2
> --- /dev/null
> +++ b/stdio-common/iovfwscanf.c
> @@ -0,0 +1,34 @@
> +/* Copyright (C) 1991-2018 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
Missing one line description.

> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <http://www.gnu.org/licenses/>.  */
> +
> +#include <libioP.h>
> +#include <shlib-compat.h>
> +
> +#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_28)
> +
> +int
> +attribute_compat_text_section
> +__IO_vfwscanf (FILE *fp, const wchar_t *format, va_list ap, int *errp)
> +{
> +  int rv = __vfwscanf_internal (fp, format, ap, 0);
> +  if (__glibc_unlikely (errp != 0))
> +    *errp = (rv == -1);
> +  return rv;
> +}
> +compat_symbol (libc, __IO_vfwscanf, _IO_vfwscanf, GLIBC_2_0);
> +
> +#endif
> diff --git a/stdio-common/isoc99_fscanf.c b/stdio-common/isoc99_fscanf.c
> index 9cdf85e679..4210d11f2b 100644
> --- a/stdio-common/isoc99_fscanf.c
> +++ b/stdio-common/isoc99_fscanf.c
> @@ -31,7 +31,7 @@ __isoc99_fscanf (FILE *stream, const char *format, ...)
>    stream->_flags2 |= _IO_FLAGS2_SCANF_STD;
>  
>    va_start (arg, format);
> -  done = _IO_vfscanf (stream, format, arg, NULL);
> +  done = __vfscanf_internal (stream, format, arg, 0);
>    va_end (arg);
>  
>    _IO_release_lock (stream);

Ok.

> diff --git a/stdio-common/isoc99_scanf.c b/stdio-common/isoc99_scanf.c
> index bf7dbe86bb..64c873eed9 100644
> --- a/stdio-common/isoc99_scanf.c
> +++ b/stdio-common/isoc99_scanf.c
> @@ -34,7 +34,7 @@ __isoc99_scanf (const char *format, ...)
>    stdin->_flags2 |= _IO_FLAGS2_SCANF_STD;
>  
>    va_start (arg, format);
> -  done = _IO_vfscanf (stdin, format, arg, NULL);
> +  done = __vfscanf_internal (stdin, format, arg, 0);
>    va_end (arg);
>  
>  #ifdef _IO_MTSAFE_IO

Ok.

> diff --git a/stdio-common/isoc99_sscanf.c b/stdio-common/isoc99_sscanf.c
> index 56a60a2c05..95b94a68b5 100644
> --- a/stdio-common/isoc99_sscanf.c
> +++ b/stdio-common/isoc99_sscanf.c
> @@ -16,8 +16,7 @@
>     <http://www.gnu.org/licenses/>.  */
>  
>  #include <stdarg.h>
> -#include <stdio.h>
> -#include <libioP.h>
> +#include <libio/strfile.h>
>  
>  /* Read formatted input from S, according to the format string FORMAT.  */
>  /* VARARGS2 */

I think you can cleanup this VARARGS2 comment as before.

> @@ -26,9 +25,12 @@ __isoc99_sscanf (const char *s, const char *format, ...)
>  {
>    va_list arg;
>    int done;
> +  _IO_strfile sf;
> +  FILE *f = _IO_strfile_read (&sf, s);
> +  f->_flags2 |= _IO_FLAGS2_SCANF_STD;
>  
>    va_start (arg, format);
> -  done = __isoc99_vsscanf (s, format, arg);
> +  done = __vfscanf_internal (f, format, arg, 0);
>    va_end (arg);
>  
>    return done;

Ok.

> diff --git a/stdio-common/isoc99_vfscanf.c b/stdio-common/isoc99_vfscanf.c
> index b80e05f8db..c96ca831ae 100644
> --- a/stdio-common/isoc99_vfscanf.c
> +++ b/stdio-common/isoc99_vfscanf.c
> @@ -27,7 +27,7 @@ __isoc99_vfscanf (FILE *stream, const char *format, va_list args)
>  
>    _IO_acquire_lock_clear_flags2 (stream);
>    stream->_flags2 |= _IO_FLAGS2_SCANF_STD;
> -  done = _IO_vfscanf (stream, format, args, NULL);
> +  done = __vfscanf_internal (stream, format, args, 0);
>    _IO_release_lock (stream);
>    return done;
>  }

Ok.

> diff --git a/stdio-common/isoc99_vscanf.c b/stdio-common/isoc99_vscanf.c
> index 0b747f85ba..72ae72ddee 100644
> --- a/stdio-common/isoc99_vscanf.c
> +++ b/stdio-common/isoc99_vscanf.c
> @@ -27,7 +27,7 @@ __isoc99_vscanf (const char *format, va_list args)
>  
>    _IO_acquire_lock_clear_flags2 (stdin);
>    stdin->_flags2 |= _IO_FLAGS2_SCANF_STD;
> -  done = _IO_vfscanf (stdin, format, args, NULL);
> +  done = __vfscanf_internal (stdin, format, args, 0);
>    _IO_release_lock (stdin);
>    return done;
>  }

Ok.

> diff --git a/stdio-common/isoc99_vsscanf.c b/stdio-common/isoc99_vsscanf.c
> index ac85ef2d0d..02bc0f50e6 100644
> --- a/stdio-common/isoc99_vsscanf.c
> +++ b/stdio-common/isoc99_vsscanf.c
> @@ -24,23 +24,14 @@
>     This exception applies to code released by its copyright holders
>     in files containing the exception.  */
>  
> -#include <libioP.h>
> -#include <stdio.h>
> -#include "../libio/strfile.h"
> +#include <libio/strfile.h>
>  
>  int
>  __isoc99_vsscanf (const char *string, const char *format, va_list args)
>  {
> -  int ret;
>    _IO_strfile sf;
> -#ifdef _IO_MTSAFE_IO
> -  sf._sbf._f._lock = NULL;
> -#endif
> -  _IO_no_init (&sf._sbf._f, _IO_USER_LOCK, -1, NULL, NULL);
> -  _IO_JUMPS (&sf._sbf) = &_IO_str_jumps;
> -  _IO_str_init_static_internal (&sf, (char*)string, 0, NULL);
> -  sf._sbf._f._flags2 |= _IO_FLAGS2_SCANF_STD;
> -  ret = _IO_vfscanf (&sf._sbf._f, format, args, NULL);
> -  return ret;
> +  FILE *f = _IO_strfile_read (&sf, string);
> +  f->_flags2 |= _IO_FLAGS2_SCANF_STD;
> +  return __vfscanf_internal (f, format, args, 0);
>  }
>  libc_hidden_def (__isoc99_vsscanf)

Ok.

> diff --git a/stdio-common/scanf.c b/stdio-common/scanf.c
> index e61b5f1ad3..de38d70353 100644
> --- a/stdio-common/scanf.c
> +++ b/stdio-common/scanf.c
> @@ -30,7 +30,7 @@ __scanf (const char *format, ...)
>    int done;
>  
>    va_start (arg, format);
> -  done = _IO_vfscanf (stdin, format, arg, NULL);
> +  done = __vfscanf_internal (stdin, format, arg, 0);
>    va_end (arg);
>  
>    return done;

Ok.

> diff --git a/stdio-common/sscanf.c b/stdio-common/sscanf.c
> index 88cd641798..e25e9c27a5 100644
> --- a/stdio-common/sscanf.c
> +++ b/stdio-common/sscanf.c
> @@ -16,26 +16,24 @@
>     <http://www.gnu.org/licenses/>.  */
>  
>  #include <stdarg.h>
> -#include <stdio.h>
> -#include <libioP.h>
> -#define __vsscanf(s, f, a) _IO_vsscanf (s, f, a)
> +#include <libio/strfile.h>
>  
>  /* Read formatted input from S, according to the format string FORMAT.  */
> -/* VARARGS2 */
> +
>  int
>  __sscanf (const char *s, const char *format, ...)
>  {
>    va_list arg;
>    int done;
> +  _IO_strfile sf;
> +  FILE *f = _IO_strfile_read (&sf, s);
>  
>    va_start (arg, format);
> -  done = __vsscanf (s, format, arg);
> +  done = __vfscanf_internal (f, format, arg, 0);
>    va_end (arg);
>  
>    return done;
>  }
>  ldbl_hidden_def (__sscanf, sscanf)
>  ldbl_strong_alias (__sscanf, sscanf)
> -#undef _IO_sscanf
> -/* This is for libg++.  */
>  ldbl_strong_alias (__sscanf, _IO_sscanf)

Ok.

> diff --git a/stdio-common/vfscanf.c b/stdio-common/vfscanf-internal.c
> similarity index 98%
> rename from stdio-common/vfscanf.c
> rename to stdio-common/vfscanf-internal.c
> index 3263268c7e..93b07ad4bc 100644
> --- a/stdio-common/vfscanf.c
> +++ b/stdio-common/vfscanf-internal.c
> @@ -132,16 +132,13 @@
>  #include "printf-parse.h" /* Use read_int.  */
>  
>  #define encode_error() do {						      \
> -			  errval = 4;					      \
>  			  __set_errno (EILSEQ);				      \
>  			  goto errout;					      \
>  			} while (0)
>  #define conv_error()	do {						      \
> -			  errval = 2;					      \
>  			  goto errout;					      \
>  			} while (0)
>  #define input_error()	do {						      \
> -			  errval = 1;					      \
>  			  if (done == 0) done = EOF;			      \
>  			  goto errout;					      \
>  			} while (0)
> @@ -267,12 +264,12 @@ char_buffer_add (struct char_buffer *buffer, CHAR_T ch)
>     Return the number of assignments made, or -1 for an input error.  */
>  #ifdef COMPILE_WSCANF
>  int
> -_IO_vfwscanf (FILE *s, const wchar_t *format, va_list argptr,
> -	      int *errp)
> +__vfwscanf_internal (FILE *s, const wchar_t *format, va_list argptr,
> +                     unsigned int mode_flags)
>  #else
>  int
> -_IO_vfscanf_internal (FILE *s, const char *format, va_list argptr,
> -		      int *errp)
> +__vfscanf_internal (FILE *s, const char *format, va_list argptr,
> +                    unsigned int mode_flags)
>  #endif
>  {
>    va_list arg;
> @@ -283,7 +280,6 @@ _IO_vfscanf_internal (FILE *s, const char *format, va_list argptr,
>    WINT_T c = 0;	/* Last char read.  */
>    int width;		/* Maximum field width.  */
>    int flags;		/* Modifiers for current format element.  */
> -  int errval = 0;
>  #ifndef COMPILE_WSCANF
>    locale_t loc = _NL_CURRENT_LOCALE;
>    struct __locale_data *const curctype = loc->__locales[LC_CTYPE];
> @@ -335,6 +331,14 @@ _IO_vfscanf_internal (FILE *s, const char *format, va_list argptr,
>    struct char_buffer charbuf;
>    scratch_buffer_init (&charbuf.scratch);
>  
> +#define LDBL_DISTINCT (__glibc_likely ((mode_flags & SCANF_LDBL_IS_DBL) == 0))
> +#define USE_ISOC99_A  (__glibc_likely (mode_flags & SCANF_ISOC99_A))
> +  /* Temporarily honor the environmental mode bits.  */
> +  if (__ldbl_is_dbl)
> +    mode_flags |= SCANF_LDBL_IS_DBL;
> +  if (s->_flags2 & _IO_FLAGS2_SCANF_STD)
> +    mode_flags |= SCANF_ISOC99_A;
> +
>  #ifdef __va_copy
>    __va_copy (arg, argptr);
>  #else
> @@ -566,7 +570,7 @@ _IO_vfscanf_internal (FILE *s, const char *format, va_list argptr,
>  	    }
>  	  /* In __isoc99_*scanf %as, %aS and %a[ extension is not
>  	     supported at all.  */
> -	  if (s->_flags2 & _IO_FLAGS2_SCANF_STD)
> +	  if (USE_ISOC99_A)
>  	    {
>  	      --f;
>  	      break;
> @@ -2422,7 +2426,7 @@ _IO_vfscanf_internal (FILE *s, const char *format, va_list argptr,
>  	      done = EOF;
>  	      goto errout;
>  	    }
> -	  if ((flags & LONGDBL) && !__ldbl_is_dbl)
> +	  if ((flags & LONGDBL) && LDBL_DISTINCT)
>  	    {
>  	      long double d = __strtold_internal
>  		(char_buffer_start (&charbuf), &tw, flags & GROUP);
> @@ -3017,8 +3021,6 @@ _IO_vfscanf_internal (FILE *s, const char *format, va_list argptr,
>    UNLOCK_STREAM (s);
>  
>    scratch_buffer_free (&charbuf.scratch);
> -  if (errp != NULL)
> -    *errp |= errval;
>  
>    if (__glibc_unlikely (done == EOF))
>      {
> @@ -3044,23 +3046,3 @@ _IO_vfscanf_internal (FILE *s, const char *format, va_list argptr,
>      }
>    return done;
>  }
> -
> -#ifdef COMPILE_WSCANF
> -int
> -__vfwscanf (FILE *s, const wchar_t *format, va_list argptr)
> -{
> -  return _IO_vfwscanf (s, format, argptr, NULL);
> -}
> -ldbl_weak_alias (__vfwscanf, vfwscanf)
> -#else
> -int
> -___vfscanf (FILE *s, const char *format, va_list argptr)
> -{
> -  return _IO_vfscanf_internal (s, format, argptr, NULL);
> -}
> -ldbl_strong_alias (_IO_vfscanf_internal, _IO_vfscanf)
> -ldbl_hidden_def (_IO_vfscanf_internal, _IO_vfscanf)
> -ldbl_strong_alias (___vfscanf, __vfscanf)
> -ldbl_hidden_def (___vfscanf, __vfscanf)
> -ldbl_weak_alias (___vfscanf, vfscanf)
> -#endif

Ok.

> diff --git a/stdio-common/vfscanf.c b/stdio-common/vfscanf.c
> index 0000000000..5eedca8340 100644
> --- /dev/null	2018-02-21 11:21:31.435874074 -0500
> +++ b/stdio-common/vfscanf.c	2018-03-07 08:44:37.578545222 -0500
> @@ -0,0 +1,27 @@
> +/* Copyright (C) 1991-2018 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.

Missing one line description.

> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <http://www.gnu.org/licenses/>.  */
> +
> +#include <libioP.h>
> +
> +int
> +___vfscanf (FILE *s, const char *format, va_list argptr)
> +{
> +  return __vfscanf_internal (s, format, argptr, 0);
> +}
> +ldbl_strong_alias (___vfscanf, __vfscanf)
> +ldbl_hidden_def (___vfscanf, __vfscanf)
> +ldbl_weak_alias (___vfscanf, vfscanf)

Ok.

> diff --git a/stdio-common/vfwscanf.c b/stdio-common/vfwscanf-internal.c
> similarity index 50%
> rename from stdio-common/vfscanf.c
> rename to stdio-common/vfscanf-internal.c
> index 26b1a66608..26c89270b7 100644
> --- a/stdio-common/vfwscanf.c
> +++ b/stdio-common/vfwscanf-internal.c
> @@ -1,2 +1,2 @@
>  #define COMPILE_WSCANF	1
> -#include "vfscanf.c"
> +#include "vfscanf-internal.c"

Ok.

> diff --git a/stdio-common/vfwscanf.c b/stdio-common/vfwscanf.c
> new file mode 100644
> index 0000000000..0554b7eae1
> --- a/stdio-common/vfwscanf.c
> +++ b/stdio-common/vfwscanf.c
> @@ -0,0 +1,25 @@
> +/* Copyright (C) 1991-2018 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
Missing one line description.

> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <http://www.gnu.org/licenses/>.  */
> +
> +#include <libioP.h>
> +
> +int
> +__vfwscanf (FILE *s, const wchar_t *format, va_list argptr)
> +{
> +  return __vfwscanf_internal (s, format, argptr, 0);
> +}
> +ldbl_weak_alias (__vfwscanf, vfwscanf)

Ok.

> diff --git a/sysdeps/generic/math_ldbl_opt.h b/sysdeps/generic/math_ldbl_opt.h
> index 8a5d8ba107..92f670dff7 100644
> --- a/sysdeps/generic/math_ldbl_opt.h
> +++ b/sysdeps/generic/math_ldbl_opt.h
> @@ -6,9 +6,13 @@
>     for platforms where compatibility symbols are required for a previous
>     ABI that defined long double functions as aliases for the double code.  */
>  
> +#include <shlib-compat.h>
> +
>  #define LONG_DOUBLE_COMPAT(lib, introduced) 0
>  #define long_double_symbol(lib, local, symbol)
>  #define ldbl_hidden_def(local, name) libc_hidden_def (name)
>  #define ldbl_strong_alias(name, aliasname) strong_alias (name, aliasname)
>  #define ldbl_weak_alias(name, aliasname) weak_alias (name, aliasname)
> +#define ldbl_compat_symbol(lib, local, symbol, version) \
> +  compat_symbol (lib, local, symbol, version)
>  #define __ldbl_is_dbl 0

Isn't the idea that if long double being a different type than double the compat
symbols are not really required? I think this should be just an empty macro.

> diff --git a/sysdeps/ieee754/ldbl-opt/math_ldbl_opt.h b/sysdeps/ieee754/ldbl-opt/math_ldbl_opt.h
> index af861c11ea..ee70d085fd 100644
> --- a/sysdeps/ieee754/ldbl-opt/math_ldbl_opt.h
> +++ b/sysdeps/ieee754/ldbl-opt/math_ldbl_opt.h
> @@ -20,10 +20,14 @@
>    long_double_symbol (libc, __GL_##name##_##aliasname, aliasname);
>  # define long_double_symbol_1(lib, local, symbol, version) \
>    versioned_symbol (lib, local, symbol, version)
> +# define ldbl_compat_symbol(lib, local, symbol, version) \
> +  compat_symbol (lib, local, symbol, LONG_DOUBLE_COMPAT_VERSION)
>  #else
>  # define ldbl_hidden_def(local, name) libc_hidden_def (name)
>  # define ldbl_strong_alias(name, aliasname) strong_alias (name, aliasname)
>  # define ldbl_weak_alias(name, aliasname) weak_alias (name, aliasname)
> +# define ldbl_compat_symbol(lib, local, symbol, version) \
> +  compat_symbol (lib, local, symbol, version)
>  # ifndef __ASSEMBLER__
>  /* Note that weak_alias cannot be used - it is defined to nothing
>     in most of the C files.  */

Ok.

> diff --git a/sysdeps/ieee754/ldbl-opt/nldbl-compat.c b/sysdeps/ieee754/ldbl-opt/nldbl-compat.c
> index 7d19eaba8d..9ac88deb74 100644
> --- a/sysdeps/ieee754/ldbl-opt/nldbl-compat.c
> +++ b/sysdeps/ieee754/ldbl-opt/nldbl-compat.c
> @@ -329,16 +329,20 @@ __nldbl_wprintf (const wchar_t *fmt, ...)
>    return done;
>  }
>  
> +#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_28)
>  int
>  attribute_compat_text_section
>  __nldbl__IO_vfscanf (FILE *s, const char *fmt, va_list ap, int *errp)
>  {
>    int res;
>    set_no_long_double ();
> -  res = _IO_vfscanf (s, fmt, ap, errp);
> +  res = __vfscanf_internal (s, fmt, ap, 0);
>    clear_no_long_double ();
> +  if (__glibc_unlikely (errp != 0))
> +    *errp = (res == -1);
>    return res;
>  }
> +#endif
>  
>  int
>  attribute_compat_text_section
> @@ -346,7 +350,7 @@ __nldbl___vfscanf (FILE *s, const char *fmt, va_list ap)
>  {
>    int res;
>    set_no_long_double ();
> -  res = _IO_vfscanf (s, fmt, ap, NULL);
> +  res = __vfscanf_internal (s, fmt, ap, 0);
>    clear_no_long_double ();
>    return res;
>  }
> @@ -422,7 +426,7 @@ __nldbl_vfwscanf (FILE *s, const wchar_t *fmt, va_list ap)
>  {
>    int res;
>    set_no_long_double ();
> -  res = _IO_vfwscanf (s, fmt, ap, NULL);
> +  res = __vfwscanf_internal (s, fmt, ap, 0);
>    clear_no_long_double ();
>    return res;
>  }
> @@ -1026,7 +1030,9 @@ compat_symbol (libc, __nldbl_vdprintf, vdprintf, GLIBC_2_0);
>  compat_symbol (libc, __nldbl_vsnprintf, vsnprintf, GLIBC_2_0);
>  compat_symbol (libc, __nldbl_vsprintf, vsprintf, GLIBC_2_0);
>  compat_symbol (libc, __nldbl__IO_sscanf, _IO_sscanf, GLIBC_2_0);
> +#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_28)
>  compat_symbol (libc, __nldbl__IO_vfscanf, _IO_vfscanf, GLIBC_2_0);
> +#endif
>  compat_symbol (libc, __nldbl___vfscanf, __vfscanf, GLIBC_2_0);
>  compat_symbol (libc, __nldbl___vsscanf, __vsscanf, GLIBC_2_0);
>  compat_symbol (libc, __nldbl_fscanf, fscanf, GLIBC_2_0);

I am not sure that nesting SHLIB_COMPAT is correct way logically and stylisc here:
the compat symbol will be create only for ABI which initial version of GLIBC_2_0
(which might not be an issue with current ABIs that requires ldbl to dbl compat
symbol).

Should we just add it on the end of the list?

> diff --git a/wcsmbs/isoc99_fwscanf.c b/wcsmbs/isoc99_fwscanf.c
> index 0c6a2c47ac..00b07dd48e 100644
> --- a/wcsmbs/isoc99_fwscanf.c
> +++ b/wcsmbs/isoc99_fwscanf.c
> @@ -32,7 +32,7 @@ __isoc99_fwscanf (FILE *stream, const wchar_t *format, ...)
>    stream->_flags2 |= _IO_FLAGS2_SCANF_STD;
>  
>    va_start (arg, format);
> -  done = _IO_vfwscanf (stream, format, arg, NULL);
> +  done = __vfwscanf_internal (stream, format, arg, 0);
>    va_end (arg);
>  
>    _IO_release_lock (stream);

Ok.

> diff --git a/wcsmbs/isoc99_swscanf.c b/wcsmbs/isoc99_swscanf.c
> index ff523db706..40401d0aa1 100644
> --- a/wcsmbs/isoc99_swscanf.c
> +++ b/wcsmbs/isoc99_swscanf.c
> @@ -16,20 +16,22 @@
>     <http://www.gnu.org/licenses/>.  */
>  
>  #include <stdarg.h>
> -#include <stdio.h>
> -#include <libioP.h>
> -#include <wchar.h>
> +#include <libio/strfile.h>
>  
>  /* Read formatted input from S, according to the format string FORMAT.  */
> -/* VARARGS2 */
> +
>  int
>  __isoc99_swscanf (const wchar_t *s, const wchar_t *format, ...)
>  {
>    va_list arg;
>    int done;
> +  _IO_strfile sf;
> +  struct _IO_wide_data wd;
> +  FILE *f = _IO_strfile_readw (&sf, &wd, s);
> +  f->_flags2 |= _IO_FLAGS2_SCANF_STD;
>  
>    va_start (arg, format);
> -  done = __isoc99_vswscanf (s, format, arg);
> +  done = __vfwscanf_internal (f, format, arg, 0);
>    va_end (arg);
>  
>    return done;

Ok.

> diff --git a/wcsmbs/isoc99_vfwscanf.c b/wcsmbs/isoc99_vfwscanf.c
> index 7beb45b4d3..f70c6b596d 100644
> --- a/wcsmbs/isoc99_vfwscanf.c
> +++ b/wcsmbs/isoc99_vfwscanf.c
> @@ -28,7 +28,7 @@ __isoc99_vfwscanf (FILE *stream, const wchar_t *format, va_list args)
>  
>    _IO_acquire_lock_clear_flags2 (stream);
>    stream->_flags2 |= _IO_FLAGS2_SCANF_STD;
> -  done = _IO_vfwscanf (stream, format, args, NULL);
> +  done = __vfwscanf_internal (stream, format, args, 0);
>    _IO_release_lock (stream);
>    return done;
>  }

Ok.

> diff --git a/wcsmbs/isoc99_vswscanf.c b/wcsmbs/isoc99_vswscanf.c
> index 130769154d..b91eb651a3 100644
> --- a/wcsmbs/isoc99_vswscanf.c
> +++ b/wcsmbs/isoc99_vswscanf.c
> @@ -24,24 +24,16 @@
>     This exception applies to code released by its copyright holders
>     in files containing the exception.  */
>  
> -#include <libioP.h>
>  #include <wchar.h>
> -#include "../libio/strfile.h"
> +#include <libio/strfile.h>
>  
>  int
>  __isoc99_vswscanf (const wchar_t *string, const wchar_t *format, va_list args)
>  {
> -  int ret;
>    _IO_strfile sf;
>    struct _IO_wide_data wd;
> -#ifdef _IO_MTSAFE_IO
> -  sf._sbf._f._lock = NULL;
> -#endif
> -  _IO_no_init (&sf._sbf._f, _IO_USER_LOCK, 0, &wd, &_IO_wstr_jumps);
> -  _IO_fwide (&sf._sbf._f, 1);
> -  _IO_wstr_init_static (&sf._sbf._f, (wchar_t *)string, 0, NULL);
> -  sf._sbf._f._flags2 |= _IO_FLAGS2_SCANF_STD;
> -  ret = _IO_vfwscanf ((FILE *) &sf._sbf, format, args, NULL);
> -  return ret;
> +  FILE *f = _IO_strfile_readw (&sf, &wd, string);
> +  f->_flags2 |= _IO_FLAGS2_SCANF_STD;
> +  return __vfwscanf_internal (f, format, args, 0);
>  }
>  libc_hidden_def (__isoc99_vswscanf)

Ok.

> diff --git a/wcsmbs/isoc99_vwscanf.c b/wcsmbs/isoc99_vwscanf.c
> index 049521b964..eb22c8acae 100644
> --- a/wcsmbs/isoc99_vwscanf.c
> +++ b/wcsmbs/isoc99_vwscanf.c
> @@ -28,7 +28,7 @@ __isoc99_vwscanf (const wchar_t *format, va_list args)
>  
>    _IO_acquire_lock_clear_flags2 (stdin);
>    stdin->_flags2 |= _IO_FLAGS2_SCANF_STD;
> -  done = _IO_vfwscanf (stdin, format, args, NULL);
> +  done = __vfwscanf_internal (stdin, format, args, 0);
>    _IO_release_lock (stdin);
>    return done;
>  }

Ok.

> diff --git a/wcsmbs/isoc99_wscanf.c b/wcsmbs/isoc99_wscanf.c
> index abfbd50c11..59f80d78fb 100644
> --- a/wcsmbs/isoc99_wscanf.c
> +++ b/wcsmbs/isoc99_wscanf.c
> @@ -33,7 +33,7 @@ __isoc99_wscanf (const wchar_t *format, ...)
>    stdin->_flags2 |= _IO_FLAGS2_SCANF_STD;
>  
>    va_start (arg, format);
> -  done = _IO_vfwscanf (stdin, format, arg, NULL);
> +  done = __vfwscanf_internal (stdin, format, arg, 0);
>    va_end (arg);
>  
>    _IO_release_lock (stdin);
> 

Ok.
Gabriel F. T. Gomes - March 26, 2018, 3:27 p.m.
On Wed, 07 Mar 2018, Zack Weinberg wrote:

>(It was necessary to introduce ldbl_compat_symbol for _IO_vfscanf.
>Please check that part of the patch very carefully, I am still not
>confident I understand all of the details of ldbl-opt.)

It looks good on powerpc64...  Oldest symbol (where long double had the
same format as double) is still there as a compat symbol with version
GLIBC_2.3...  The newer symbol, is a bit different, in the sense that it
is now a compat symbol (it was a default symbol previously).

Here's what readelf has to tell us:

Before the patch set:
  1355: 00000000001eea70   124 FUNC    GLOBAL DEFAULT   27 _IO_vfscanf@GLIBC_2.3
  1356: 00000000001f0a98 23552 FUNC    GLOBAL DEFAULT   27 _IO_vfscanf@@GLIBC_2.4

After the patch set:
  1355: 00000000001f0bd0   136 FUNC    GLOBAL DEFAULT   27 _IO_vfscanf@GLIBC_2.4
  1356: 00000000001ee968   136 FUNC    GLOBAL DEFAULT   27 _IO_vfscanf@GLIBC_2.3

For the static library, I think that Adhemerval is right (see comment below).

>	* libio/libioP.h (SCANF_LDBL_IS_DBL, SCANF_ISOC99_A): New constants.
>	(__vfscanf_internal, __vfwscanf_internal): New function prototypes.
>        * libio/libio.h: Remove libc_hidden_proto for _IO_vfscanf.
 ~~~~~~~~
Spaces instead of tabs.

>	* libio/strfile.h: Add multiple inclusion guard.

Perhaps mention the removal of stdio.h inclusion?

>        * stdio-common/Versions: Mention GLIBC_2.28, so that
>        it can be used in SHLIB_COMPAT expressions.
 ~~~~~~~~
Spaces instead of tabs.

>+extern int __vfscanf_internal (FILE *fp, const char *format, va_list argp,
>+                               unsigned int flags);
  ~~~~~~~~~~~~~~~~~~~~~~~~
>+extern int __vfwscanf_internal (FILE *fp, const wchar_t *format, va_list argp,
>+                                unsigned int flags);
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Spaces instead of tabs.

>+/* Initialize an _IO_strfile SF and _IO_wide_data WD to read from wide
>+   string STRING, and return the corresponding FILE object.  It is not
>+   necessary to fclose the FILE when it is no longer needed.  */
>+static inline FILE *
>+_IO_strfile_readw (_IO_strfile *sf, struct _IO_wide_data *wd,
>+                   const wchar_t *string)
  ~~~~~~~~~~~~~~~~
Spaces instead of tabs.

>--- /dev/null
>+++ b/stdio-common/iovfscanf.c
>@@ -0,0 +1,34 @@
>+/* Copyright (C) 1991-2018 Free Software Foundation, Inc.

Should this (and other new files) be copyright 2018, since they're new?

>--- a/stdio-common/vfscanf.c
>+++ b/stdio-common/vfscanf-internal.c
>-_IO_vfwscanf (FILE *s, const wchar_t *format, va_list argptr,
>-	      int *errp)
>+__vfwscanf_internal (FILE *s, const wchar_t *format, va_list argptr,
>+                     unsigned int mode_flags)
  ~~~~~~~~~~~~~~~~
Spaces instead of tabs.

>-_IO_vfscanf_internal (FILE *s, const char *format, va_list argptr,
>-		      int *errp)
>+__vfscanf_internal (FILE *s, const char *format, va_list argptr,
>+                    unsigned int mode_flags)
  ~~~~~~~~~~~~~~~~
Spaces instead of tabs.

>--- a/sysdeps/ieee754/ldbl-opt/math_ldbl_opt.h
>+++ b/sysdeps/ieee754/ldbl-opt/math_ldbl_opt.h
>@@ -20,10 +20,14 @@
>   long_double_symbol (libc, __GL_##name##_##aliasname, aliasname);
> # define long_double_symbol_1(lib, local, symbol, version) \
>   versioned_symbol (lib, local, symbol, version)
>+# define ldbl_compat_symbol(lib, local, symbol, version) \
>+  compat_symbol (lib, local, symbol, LONG_DOUBLE_COMPAT_VERSION)
> #else
> # define ldbl_hidden_def(local, name) libc_hidden_def (name)
> # define ldbl_strong_alias(name, aliasname) strong_alias (name, aliasname)
> # define ldbl_weak_alias(name, aliasname) weak_alias (name, aliasname)
>+# define ldbl_compat_symbol(lib, local, symbol, version) \
>+  compat_symbol (lib, local, symbol, version)

I believe that Adhemerval's comment is correct and ldbl_compat_symbol
should translate to nothing when building static libraries.

Patch

diff --git a/libio/iovsscanf.c b/libio/iovsscanf.c
index e56ab8bd7d..ee6a99ec6a 100644
--- a/libio/iovsscanf.c
+++ b/libio/iovsscanf.c
@@ -24,22 +24,14 @@ 
    This exception applies to code released by its copyright holders
    in files containing the exception.  */
 
-#include "libioP.h"
 #include "strfile.h"
 
 int
 _IO_vsscanf (const char *string, const char *format, va_list args)
 {
-  int ret;
   _IO_strfile sf;
-#ifdef _IO_MTSAFE_IO
-  sf._sbf._f._lock = NULL;
-#endif
-  _IO_no_init (&sf._sbf._f, _IO_USER_LOCK, -1, NULL, NULL);
-  _IO_JUMPS (&sf._sbf) = &_IO_str_jumps;
-  _IO_str_init_static_internal (&sf, (char*)string, 0, NULL);
-  ret = _IO_vfscanf (&sf._sbf._f, format, args, NULL);
-  return ret;
+  FILE *f = _IO_strfile_read (&sf, string);
+  return __vfscanf_internal (f, format, args, 0);
 }
 ldbl_weak_alias (_IO_vsscanf, __vsscanf)
 ldbl_weak_alias (_IO_vsscanf, vsscanf)
diff --git a/libio/iovswscanf.c b/libio/iovswscanf.c
index 5bd1c88412..cb9cbe15cc 100644
--- a/libio/iovswscanf.c
+++ b/libio/iovswscanf.c
@@ -24,24 +24,16 @@ 
    This exception applies to code released by its copyright holders
    in files containing the exception.  */
 
-#include "libioP.h"
-#include "strfile.h"
 #include <wchar.h>
+#include "strfile.h"
 
 int
 __vswscanf (const wchar_t *string, const wchar_t *format, va_list args)
 {
-  int ret;
   _IO_strfile sf;
   struct _IO_wide_data wd;
-#ifdef _IO_MTSAFE_IO
-  sf._sbf._f._lock = NULL;
-#endif
-  _IO_no_init (&sf._sbf._f, _IO_USER_LOCK, 0, &wd, &_IO_wstr_jumps);
-  _IO_fwide (&sf._sbf._f, 1);
-  _IO_wstr_init_static (&sf._sbf._f, (wchar_t *)string, 0, NULL);
-  ret = _IO_vfwscanf ((FILE *) &sf._sbf, format, args, NULL);
-  return ret;
+  FILE *f = _IO_strfile_readw (&sf, &wd, string);
+  return __vfwscanf_internal (f, format, args, 0);
 }
 libc_hidden_def (__vswscanf)
 ldbl_hidden_def (__vswscanf, vswscanf)
diff --git a/libio/libio.h b/libio/libio.h
index 00f9169613..d4eba2df54 100644
--- a/libio/libio.h
+++ b/libio/libio.h
@@ -321,7 +321,6 @@  libc_hidden_proto (_IO_padn)
 libc_hidden_proto (_IO_putc)
 libc_hidden_proto (_IO_sgetn)
 libc_hidden_proto (_IO_vfprintf)
-libc_hidden_proto (_IO_vfscanf)
 
 #ifdef _IO_MTSAFE_IO
 # undef _IO_peekc
diff --git a/libio/libioP.h b/libio/libioP.h
index 8afe7032e3..a471c90be8 100644
--- a/libio/libioP.h
+++ b/libio/libioP.h
@@ -704,6 +704,15 @@  extern off64_t _IO_seekpos_unlocked (FILE *, off64_t, int)
 
 #endif /* _G_HAVE_MMAP */
 
+/* Flags for __vfscanf_internal and __vfwscanf_internal.  */
+#define SCANF_LDBL_IS_DBL 0x0001
+#define SCANF_ISOC99_A    0x0002
+
+extern int __vfscanf_internal (FILE *fp, const char *format, va_list argp,
+                               unsigned int flags);
+extern int __vfwscanf_internal (FILE *fp, const wchar_t *format, va_list argp,
+                                unsigned int flags);
+
 extern int _IO_vscanf (const char *, va_list) __THROW;
 
 #ifdef _IO_MTSAFE_IO
diff --git a/libio/strfile.h b/libio/strfile.h
index 46ac81809a..715149f5bd 100644
--- a/libio/strfile.h
+++ b/libio/strfile.h
@@ -24,7 +24,9 @@ 
    This exception applies to code released by its copyright holders
    in files containing the exception.  */
 
-#include <stdio.h>
+#ifndef STRFILE_H_
+#define STRFILE_H_
+
 #include "libioP.h"
 
 typedef void *(*_IO_alloc_type) (size_t);
@@ -81,3 +83,32 @@  typedef struct
 } _IO_wstrnfile;
 
 extern const struct _IO_jump_t _IO_wstrn_jumps attribute_hidden;
+
+/* Initialize an _IO_strfile SF to read from narrow string STRING, and
+   return the corresponding FILE object.  It is not necessary to fclose
+   the FILE when it is no longer needed.  */
+static inline FILE *
+_IO_strfile_read (_IO_strfile *sf, const char *string)
+{
+  sf->_sbf._f._lock = NULL;
+  _IO_no_init (&sf->_sbf._f, _IO_USER_LOCK, -1, NULL, NULL);
+  _IO_JUMPS (&sf->_sbf) = &_IO_str_jumps;
+  _IO_str_init_static_internal (sf, (char*)string, 0, NULL);
+  return &sf->_sbf._f;
+}
+
+/* Initialize an _IO_strfile SF and _IO_wide_data WD to read from wide
+   string STRING, and return the corresponding FILE object.  It is not
+   necessary to fclose the FILE when it is no longer needed.  */
+static inline FILE *
+_IO_strfile_readw (_IO_strfile *sf, struct _IO_wide_data *wd,
+                   const wchar_t *string)
+{
+  sf->_sbf._f._lock = NULL;
+  _IO_no_init (&sf->_sbf._f, _IO_USER_LOCK, 0, wd, &_IO_wstr_jumps);
+  _IO_fwide (&sf->_sbf._f, 1);
+  _IO_wstr_init_static (&sf->_sbf._f, (wchar_t *)string, 0, NULL);
+  return &sf->_sbf._f;
+}
+
+#endif /* strfile.h.  */
diff --git a/libio/swscanf.c b/libio/swscanf.c
index c8686bcbaf..90f721cc51 100644
--- a/libio/swscanf.c
+++ b/libio/swscanf.c
@@ -15,20 +15,22 @@ 
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <libioP.h>
 #include <stdarg.h>
-#include <wchar.h>
+#include "strfile.h"
 
 /* Read formatted input from S, according to the format string FORMAT.  */
-/* VARARGS2 */
+
 int
 __swscanf (const wchar_t *s, const wchar_t *format, ...)
 {
   va_list arg;
   int done;
+  _IO_strfile sf;
+  struct _IO_wide_data wd;
+  FILE *f = _IO_strfile_readw (&sf, &wd, s);
 
   va_start (arg, format);
-  done = __vswscanf (s, format, arg);
+  done = __vfwscanf_internal (f, format, arg, 0);
   va_end (arg);
 
   return done;
diff --git a/libio/vscanf.c b/libio/vscanf.c
index 9c27122c27..a3e2dd43f2 100644
--- a/libio/vscanf.c
+++ b/libio/vscanf.c
@@ -32,6 +32,6 @@ 
 int
 _IO_vscanf (const char *format, va_list args)
 {
-  return _IO_vfscanf (_IO_stdin, format, args, NULL);
+  return __vfscanf_internal (_IO_stdin, format, args, 0);
 }
 ldbl_weak_alias (_IO_vscanf, vscanf)
diff --git a/libio/vwscanf.c b/libio/vwscanf.c
index 0d5f558758..7af770c8c3 100644
--- a/libio/vwscanf.c
+++ b/libio/vwscanf.c
@@ -30,6 +30,6 @@ 
 int
 __vwscanf (const wchar_t *format, va_list args)
 {
-  return _IO_vfwscanf (_IO_stdin, format, args, NULL);
+  return __vfwscanf_internal (_IO_stdin, format, args, 0);
 }
 ldbl_strong_alias (__vwscanf, vwscanf)
diff --git a/libio/wscanf.c b/libio/wscanf.c
index c8cdad0acd..fe27ff6fa6 100644
--- a/libio/wscanf.c
+++ b/libio/wscanf.c
@@ -30,7 +30,7 @@  __wscanf (const wchar_t *format, ...)
   int done;
 
   va_start (arg, format);
-  done = _IO_vfwscanf (stdin, format, arg, NULL);
+  done = __vfwscanf_internal (stdin, format, arg, 0);
   va_end (arg);
 
   return done;
diff --git a/stdio-common/Makefile b/stdio-common/Makefile
index 9dfc115313..b7b1f01bdd 100644
--- a/stdio-common/Makefile
+++ b/stdio-common/Makefile
@@ -39,7 +39,8 @@  routines	:=							      \
 	flockfile ftrylockfile funlockfile				      \
 	isoc99_scanf isoc99_vscanf isoc99_fscanf isoc99_vfscanf isoc99_sscanf \
 	isoc99_vsscanf							      \
-	psiginfo gentempfd
+	psiginfo gentempfd						      \
+	vfscanf-internal vfwscanf-internal iovfscanf iovfwscanf
 
 aux	:= errlist siglist printf-parsemb printf-parsewc fxprintf
 
diff --git a/stdio-common/Versions b/stdio-common/Versions
index 5016f69c20..7af44949f7 100644
--- a/stdio-common/Versions
+++ b/stdio-common/Versions
@@ -57,6 +57,9 @@  libc {
     psiginfo;
     register_printf_modifier; register_printf_type; register_printf_specifier;
   }
+  GLIBC_2.28 {
+    # SHLIB_COMPAT(GLIBC_2_0, GLIBC_2_28) used in iovfscanf.c etc
+  }
   GLIBC_PRIVATE {
     # global variables
     _itoa_lower_digits;
diff --git a/stdio-common/iovfscanf.c b/stdio-common/iovfscanf.c
new file mode 100644
index 0000000000..fb347d60cb
--- /dev/null
+++ b/stdio-common/iovfscanf.c
@@ -0,0 +1,34 @@ 
+/* Copyright (C) 1991-2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <libioP.h>
+#include <shlib-compat.h>
+
+#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_28)
+
+int
+attribute_compat_text_section
+__IO_vfscanf (FILE *fp, const char *format, va_list ap, int *errp)
+{
+  int rv = __vfscanf_internal (fp, format, ap, 0);
+  if (__glibc_unlikely (errp != 0))
+    *errp = (rv == -1);
+  return rv;
+}
+ldbl_compat_symbol (libc, __IO_vfscanf, _IO_vfscanf, GLIBC_2_0);
+
+#endif
diff --git a/stdio-common/iovfwscanf.c b/stdio-common/iovfwscanf.c
new file mode 100644
index 0000000000..73936f68b2
--- /dev/null
+++ b/stdio-common/iovfwscanf.c
@@ -0,0 +1,34 @@ 
+/* Copyright (C) 1991-2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <libioP.h>
+#include <shlib-compat.h>
+
+#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_28)
+
+int
+attribute_compat_text_section
+__IO_vfwscanf (FILE *fp, const wchar_t *format, va_list ap, int *errp)
+{
+  int rv = __vfwscanf_internal (fp, format, ap, 0);
+  if (__glibc_unlikely (errp != 0))
+    *errp = (rv == -1);
+  return rv;
+}
+compat_symbol (libc, __IO_vfwscanf, _IO_vfwscanf, GLIBC_2_0);
+
+#endif
diff --git a/stdio-common/isoc99_fscanf.c b/stdio-common/isoc99_fscanf.c
index 9cdf85e679..4210d11f2b 100644
--- a/stdio-common/isoc99_fscanf.c
+++ b/stdio-common/isoc99_fscanf.c
@@ -31,7 +31,7 @@  __isoc99_fscanf (FILE *stream, const char *format, ...)
   stream->_flags2 |= _IO_FLAGS2_SCANF_STD;
 
   va_start (arg, format);
-  done = _IO_vfscanf (stream, format, arg, NULL);
+  done = __vfscanf_internal (stream, format, arg, 0);
   va_end (arg);
 
   _IO_release_lock (stream);
diff --git a/stdio-common/isoc99_scanf.c b/stdio-common/isoc99_scanf.c
index bf7dbe86bb..64c873eed9 100644
--- a/stdio-common/isoc99_scanf.c
+++ b/stdio-common/isoc99_scanf.c
@@ -34,7 +34,7 @@  __isoc99_scanf (const char *format, ...)
   stdin->_flags2 |= _IO_FLAGS2_SCANF_STD;
 
   va_start (arg, format);
-  done = _IO_vfscanf (stdin, format, arg, NULL);
+  done = __vfscanf_internal (stdin, format, arg, 0);
   va_end (arg);
 
 #ifdef _IO_MTSAFE_IO
diff --git a/stdio-common/isoc99_sscanf.c b/stdio-common/isoc99_sscanf.c
index 56a60a2c05..95b94a68b5 100644
--- a/stdio-common/isoc99_sscanf.c
+++ b/stdio-common/isoc99_sscanf.c
@@ -16,8 +16,7 @@ 
    <http://www.gnu.org/licenses/>.  */
 
 #include <stdarg.h>
-#include <stdio.h>
-#include <libioP.h>
+#include <libio/strfile.h>
 
 /* Read formatted input from S, according to the format string FORMAT.  */
 /* VARARGS2 */
@@ -26,9 +25,12 @@  __isoc99_sscanf (const char *s, const char *format, ...)
 {
   va_list arg;
   int done;
+  _IO_strfile sf;
+  FILE *f = _IO_strfile_read (&sf, s);
+  f->_flags2 |= _IO_FLAGS2_SCANF_STD;
 
   va_start (arg, format);
-  done = __isoc99_vsscanf (s, format, arg);
+  done = __vfscanf_internal (f, format, arg, 0);
   va_end (arg);
 
   return done;
diff --git a/stdio-common/isoc99_vfscanf.c b/stdio-common/isoc99_vfscanf.c
index b80e05f8db..c96ca831ae 100644
--- a/stdio-common/isoc99_vfscanf.c
+++ b/stdio-common/isoc99_vfscanf.c
@@ -27,7 +27,7 @@  __isoc99_vfscanf (FILE *stream, const char *format, va_list args)
 
   _IO_acquire_lock_clear_flags2 (stream);
   stream->_flags2 |= _IO_FLAGS2_SCANF_STD;
-  done = _IO_vfscanf (stream, format, args, NULL);
+  done = __vfscanf_internal (stream, format, args, 0);
   _IO_release_lock (stream);
   return done;
 }
diff --git a/stdio-common/isoc99_vscanf.c b/stdio-common/isoc99_vscanf.c
index 0b747f85ba..72ae72ddee 100644
--- a/stdio-common/isoc99_vscanf.c
+++ b/stdio-common/isoc99_vscanf.c
@@ -27,7 +27,7 @@  __isoc99_vscanf (const char *format, va_list args)
 
   _IO_acquire_lock_clear_flags2 (stdin);
   stdin->_flags2 |= _IO_FLAGS2_SCANF_STD;
-  done = _IO_vfscanf (stdin, format, args, NULL);
+  done = __vfscanf_internal (stdin, format, args, 0);
   _IO_release_lock (stdin);
   return done;
 }
diff --git a/stdio-common/isoc99_vsscanf.c b/stdio-common/isoc99_vsscanf.c
index ac85ef2d0d..02bc0f50e6 100644
--- a/stdio-common/isoc99_vsscanf.c
+++ b/stdio-common/isoc99_vsscanf.c
@@ -24,23 +24,14 @@ 
    This exception applies to code released by its copyright holders
    in files containing the exception.  */
 
-#include <libioP.h>
-#include <stdio.h>
-#include "../libio/strfile.h"
+#include <libio/strfile.h>
 
 int
 __isoc99_vsscanf (const char *string, const char *format, va_list args)
 {
-  int ret;
   _IO_strfile sf;
-#ifdef _IO_MTSAFE_IO
-  sf._sbf._f._lock = NULL;
-#endif
-  _IO_no_init (&sf._sbf._f, _IO_USER_LOCK, -1, NULL, NULL);
-  _IO_JUMPS (&sf._sbf) = &_IO_str_jumps;
-  _IO_str_init_static_internal (&sf, (char*)string, 0, NULL);
-  sf._sbf._f._flags2 |= _IO_FLAGS2_SCANF_STD;
-  ret = _IO_vfscanf (&sf._sbf._f, format, args, NULL);
-  return ret;
+  FILE *f = _IO_strfile_read (&sf, string);
+  f->_flags2 |= _IO_FLAGS2_SCANF_STD;
+  return __vfscanf_internal (f, format, args, 0);
 }
 libc_hidden_def (__isoc99_vsscanf)
diff --git a/stdio-common/scanf.c b/stdio-common/scanf.c
index e61b5f1ad3..de38d70353 100644
--- a/stdio-common/scanf.c
+++ b/stdio-common/scanf.c
@@ -30,7 +30,7 @@  __scanf (const char *format, ...)
   int done;
 
   va_start (arg, format);
-  done = _IO_vfscanf (stdin, format, arg, NULL);
+  done = __vfscanf_internal (stdin, format, arg, 0);
   va_end (arg);
 
   return done;
diff --git a/stdio-common/sscanf.c b/stdio-common/sscanf.c
index 88cd641798..e25e9c27a5 100644
--- a/stdio-common/sscanf.c
+++ b/stdio-common/sscanf.c
@@ -16,26 +16,24 @@ 
    <http://www.gnu.org/licenses/>.  */
 
 #include <stdarg.h>
-#include <stdio.h>
-#include <libioP.h>
-#define __vsscanf(s, f, a) _IO_vsscanf (s, f, a)
+#include <libio/strfile.h>
 
 /* Read formatted input from S, according to the format string FORMAT.  */
-/* VARARGS2 */
+
 int
 __sscanf (const char *s, const char *format, ...)
 {
   va_list arg;
   int done;
+  _IO_strfile sf;
+  FILE *f = _IO_strfile_read (&sf, s);
 
   va_start (arg, format);
-  done = __vsscanf (s, format, arg);
+  done = __vfscanf_internal (f, format, arg, 0);
   va_end (arg);
 
   return done;
 }
 ldbl_hidden_def (__sscanf, sscanf)
 ldbl_strong_alias (__sscanf, sscanf)
-#undef _IO_sscanf
-/* This is for libg++.  */
 ldbl_strong_alias (__sscanf, _IO_sscanf)
diff --git a/stdio-common/vfscanf.c b/stdio-common/vfscanf-internal.c
similarity index 98%
rename from stdio-common/vfscanf.c
rename to stdio-common/vfscanf-internal.c
index 3263268c7e..93b07ad4bc 100644
--- a/stdio-common/vfscanf.c
+++ b/stdio-common/vfscanf-internal.c
@@ -132,16 +132,13 @@ 
 #include "printf-parse.h" /* Use read_int.  */
 
 #define encode_error() do {						      \
-			  errval = 4;					      \
 			  __set_errno (EILSEQ);				      \
 			  goto errout;					      \
 			} while (0)
 #define conv_error()	do {						      \
-			  errval = 2;					      \
 			  goto errout;					      \
 			} while (0)
 #define input_error()	do {						      \
-			  errval = 1;					      \
 			  if (done == 0) done = EOF;			      \
 			  goto errout;					      \
 			} while (0)
@@ -267,12 +264,12 @@  char_buffer_add (struct char_buffer *buffer, CHAR_T ch)
    Return the number of assignments made, or -1 for an input error.  */
 #ifdef COMPILE_WSCANF
 int
-_IO_vfwscanf (FILE *s, const wchar_t *format, va_list argptr,
-	      int *errp)
+__vfwscanf_internal (FILE *s, const wchar_t *format, va_list argptr,
+                     unsigned int mode_flags)
 #else
 int
-_IO_vfscanf_internal (FILE *s, const char *format, va_list argptr,
-		      int *errp)
+__vfscanf_internal (FILE *s, const char *format, va_list argptr,
+                    unsigned int mode_flags)
 #endif
 {
   va_list arg;
@@ -283,7 +280,6 @@  _IO_vfscanf_internal (FILE *s, const char *format, va_list argptr,
   WINT_T c = 0;	/* Last char read.  */
   int width;		/* Maximum field width.  */
   int flags;		/* Modifiers for current format element.  */
-  int errval = 0;
 #ifndef COMPILE_WSCANF
   locale_t loc = _NL_CURRENT_LOCALE;
   struct __locale_data *const curctype = loc->__locales[LC_CTYPE];
@@ -335,6 +331,14 @@  _IO_vfscanf_internal (FILE *s, const char *format, va_list argptr,
   struct char_buffer charbuf;
   scratch_buffer_init (&charbuf.scratch);
 
+#define LDBL_DISTINCT (__glibc_likely ((mode_flags & SCANF_LDBL_IS_DBL) == 0))
+#define USE_ISOC99_A  (__glibc_likely (mode_flags & SCANF_ISOC99_A))
+  /* Temporarily honor the environmental mode bits.  */
+  if (__ldbl_is_dbl)
+    mode_flags |= SCANF_LDBL_IS_DBL;
+  if (s->_flags2 & _IO_FLAGS2_SCANF_STD)
+    mode_flags |= SCANF_ISOC99_A;
+
 #ifdef __va_copy
   __va_copy (arg, argptr);
 #else
@@ -566,7 +570,7 @@  _IO_vfscanf_internal (FILE *s, const char *format, va_list argptr,
 	    }
 	  /* In __isoc99_*scanf %as, %aS and %a[ extension is not
 	     supported at all.  */
-	  if (s->_flags2 & _IO_FLAGS2_SCANF_STD)
+	  if (USE_ISOC99_A)
 	    {
 	      --f;
 	      break;
@@ -2422,7 +2426,7 @@  _IO_vfscanf_internal (FILE *s, const char *format, va_list argptr,
 	      done = EOF;
 	      goto errout;
 	    }
-	  if ((flags & LONGDBL) && !__ldbl_is_dbl)
+	  if ((flags & LONGDBL) && LDBL_DISTINCT)
 	    {
 	      long double d = __strtold_internal
 		(char_buffer_start (&charbuf), &tw, flags & GROUP);
@@ -3017,8 +3021,6 @@  _IO_vfscanf_internal (FILE *s, const char *format, va_list argptr,
   UNLOCK_STREAM (s);
 
   scratch_buffer_free (&charbuf.scratch);
-  if (errp != NULL)
-    *errp |= errval;
 
   if (__glibc_unlikely (done == EOF))
     {
@@ -3044,23 +3046,3 @@  _IO_vfscanf_internal (FILE *s, const char *format, va_list argptr,
     }
   return done;
 }
-
-#ifdef COMPILE_WSCANF
-int
-__vfwscanf (FILE *s, const wchar_t *format, va_list argptr)
-{
-  return _IO_vfwscanf (s, format, argptr, NULL);
-}
-ldbl_weak_alias (__vfwscanf, vfwscanf)
-#else
-int
-___vfscanf (FILE *s, const char *format, va_list argptr)
-{
-  return _IO_vfscanf_internal (s, format, argptr, NULL);
-}
-ldbl_strong_alias (_IO_vfscanf_internal, _IO_vfscanf)
-ldbl_hidden_def (_IO_vfscanf_internal, _IO_vfscanf)
-ldbl_strong_alias (___vfscanf, __vfscanf)
-ldbl_hidden_def (___vfscanf, __vfscanf)
-ldbl_weak_alias (___vfscanf, vfscanf)
-#endif
diff --git a/stdio-common/vfscanf.c b/stdio-common/vfscanf.c
index 0000000000..5eedca8340 100644
--- /dev/null	2018-02-21 11:21:31.435874074 -0500
+++ b/stdio-common/vfscanf.c	2018-03-07 08:44:37.578545222 -0500
@@ -0,0 +1,27 @@ 
+/* Copyright (C) 1991-2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <libioP.h>
+
+int
+___vfscanf (FILE *s, const char *format, va_list argptr)
+{
+  return __vfscanf_internal (s, format, argptr, 0);
+}
+ldbl_strong_alias (___vfscanf, __vfscanf)
+ldbl_hidden_def (___vfscanf, __vfscanf)
+ldbl_weak_alias (___vfscanf, vfscanf)
diff --git a/stdio-common/vfwscanf.c b/stdio-common/vfwscanf-internal.c
similarity index 50%
rename from stdio-common/vfscanf.c
rename to stdio-common/vfscanf-internal.c
index 26b1a66608..26c89270b7 100644
--- a/stdio-common/vfwscanf.c
+++ b/stdio-common/vfwscanf-internal.c
@@ -1,2 +1,2 @@ 
 #define COMPILE_WSCANF	1
-#include "vfscanf.c"
+#include "vfscanf-internal.c"
diff --git a/stdio-common/vfwscanf.c b/stdio-common/vfwscanf.c
new file mode 100644
index 0000000000..0554b7eae1
--- a/stdio-common/vfwscanf.c
+++ b/stdio-common/vfwscanf.c
@@ -0,0 +1,25 @@ 
+/* Copyright (C) 1991-2018 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <libioP.h>
+
+int
+__vfwscanf (FILE *s, const wchar_t *format, va_list argptr)
+{
+  return __vfwscanf_internal (s, format, argptr, 0);
+}
+ldbl_weak_alias (__vfwscanf, vfwscanf)
diff --git a/sysdeps/generic/math_ldbl_opt.h b/sysdeps/generic/math_ldbl_opt.h
index 8a5d8ba107..92f670dff7 100644
--- a/sysdeps/generic/math_ldbl_opt.h
+++ b/sysdeps/generic/math_ldbl_opt.h
@@ -6,9 +6,13 @@ 
    for platforms where compatibility symbols are required for a previous
    ABI that defined long double functions as aliases for the double code.  */
 
+#include <shlib-compat.h>
+
 #define LONG_DOUBLE_COMPAT(lib, introduced) 0
 #define long_double_symbol(lib, local, symbol)
 #define ldbl_hidden_def(local, name) libc_hidden_def (name)
 #define ldbl_strong_alias(name, aliasname) strong_alias (name, aliasname)
 #define ldbl_weak_alias(name, aliasname) weak_alias (name, aliasname)
+#define ldbl_compat_symbol(lib, local, symbol, version) \
+  compat_symbol (lib, local, symbol, version)
 #define __ldbl_is_dbl 0
diff --git a/sysdeps/ieee754/ldbl-opt/math_ldbl_opt.h b/sysdeps/ieee754/ldbl-opt/math_ldbl_opt.h
index af861c11ea..ee70d085fd 100644
--- a/sysdeps/ieee754/ldbl-opt/math_ldbl_opt.h
+++ b/sysdeps/ieee754/ldbl-opt/math_ldbl_opt.h
@@ -20,10 +20,14 @@ 
   long_double_symbol (libc, __GL_##name##_##aliasname, aliasname);
 # define long_double_symbol_1(lib, local, symbol, version) \
   versioned_symbol (lib, local, symbol, version)
+# define ldbl_compat_symbol(lib, local, symbol, version) \
+  compat_symbol (lib, local, symbol, LONG_DOUBLE_COMPAT_VERSION)
 #else
 # define ldbl_hidden_def(local, name) libc_hidden_def (name)
 # define ldbl_strong_alias(name, aliasname) strong_alias (name, aliasname)
 # define ldbl_weak_alias(name, aliasname) weak_alias (name, aliasname)
+# define ldbl_compat_symbol(lib, local, symbol, version) \
+  compat_symbol (lib, local, symbol, version)
 # ifndef __ASSEMBLER__
 /* Note that weak_alias cannot be used - it is defined to nothing
    in most of the C files.  */
diff --git a/sysdeps/ieee754/ldbl-opt/nldbl-compat.c b/sysdeps/ieee754/ldbl-opt/nldbl-compat.c
index 7d19eaba8d..9ac88deb74 100644
--- a/sysdeps/ieee754/ldbl-opt/nldbl-compat.c
+++ b/sysdeps/ieee754/ldbl-opt/nldbl-compat.c
@@ -329,16 +329,20 @@  __nldbl_wprintf (const wchar_t *fmt, ...)
   return done;
 }
 
+#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_28)
 int
 attribute_compat_text_section
 __nldbl__IO_vfscanf (FILE *s, const char *fmt, va_list ap, int *errp)
 {
   int res;
   set_no_long_double ();
-  res = _IO_vfscanf (s, fmt, ap, errp);
+  res = __vfscanf_internal (s, fmt, ap, 0);
   clear_no_long_double ();
+  if (__glibc_unlikely (errp != 0))
+    *errp = (res == -1);
   return res;
 }
+#endif
 
 int
 attribute_compat_text_section
@@ -346,7 +350,7 @@  __nldbl___vfscanf (FILE *s, const char *fmt, va_list ap)
 {
   int res;
   set_no_long_double ();
-  res = _IO_vfscanf (s, fmt, ap, NULL);
+  res = __vfscanf_internal (s, fmt, ap, 0);
   clear_no_long_double ();
   return res;
 }
@@ -422,7 +426,7 @@  __nldbl_vfwscanf (FILE *s, const wchar_t *fmt, va_list ap)
 {
   int res;
   set_no_long_double ();
-  res = _IO_vfwscanf (s, fmt, ap, NULL);
+  res = __vfwscanf_internal (s, fmt, ap, 0);
   clear_no_long_double ();
   return res;
 }
@@ -1026,7 +1030,9 @@  compat_symbol (libc, __nldbl_vdprintf, vdprintf, GLIBC_2_0);
 compat_symbol (libc, __nldbl_vsnprintf, vsnprintf, GLIBC_2_0);
 compat_symbol (libc, __nldbl_vsprintf, vsprintf, GLIBC_2_0);
 compat_symbol (libc, __nldbl__IO_sscanf, _IO_sscanf, GLIBC_2_0);
+#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_28)
 compat_symbol (libc, __nldbl__IO_vfscanf, _IO_vfscanf, GLIBC_2_0);
+#endif
 compat_symbol (libc, __nldbl___vfscanf, __vfscanf, GLIBC_2_0);
 compat_symbol (libc, __nldbl___vsscanf, __vsscanf, GLIBC_2_0);
 compat_symbol (libc, __nldbl_fscanf, fscanf, GLIBC_2_0);
diff --git a/wcsmbs/isoc99_fwscanf.c b/wcsmbs/isoc99_fwscanf.c
index 0c6a2c47ac..00b07dd48e 100644
--- a/wcsmbs/isoc99_fwscanf.c
+++ b/wcsmbs/isoc99_fwscanf.c
@@ -32,7 +32,7 @@  __isoc99_fwscanf (FILE *stream, const wchar_t *format, ...)
   stream->_flags2 |= _IO_FLAGS2_SCANF_STD;
 
   va_start (arg, format);
-  done = _IO_vfwscanf (stream, format, arg, NULL);
+  done = __vfwscanf_internal (stream, format, arg, 0);
   va_end (arg);
 
   _IO_release_lock (stream);
diff --git a/wcsmbs/isoc99_swscanf.c b/wcsmbs/isoc99_swscanf.c
index ff523db706..40401d0aa1 100644
--- a/wcsmbs/isoc99_swscanf.c
+++ b/wcsmbs/isoc99_swscanf.c
@@ -16,20 +16,22 @@ 
    <http://www.gnu.org/licenses/>.  */
 
 #include <stdarg.h>
-#include <stdio.h>
-#include <libioP.h>
-#include <wchar.h>
+#include <libio/strfile.h>
 
 /* Read formatted input from S, according to the format string FORMAT.  */
-/* VARARGS2 */
+
 int
 __isoc99_swscanf (const wchar_t *s, const wchar_t *format, ...)
 {
   va_list arg;
   int done;
+  _IO_strfile sf;
+  struct _IO_wide_data wd;
+  FILE *f = _IO_strfile_readw (&sf, &wd, s);
+  f->_flags2 |= _IO_FLAGS2_SCANF_STD;
 
   va_start (arg, format);
-  done = __isoc99_vswscanf (s, format, arg);
+  done = __vfwscanf_internal (f, format, arg, 0);
   va_end (arg);
 
   return done;
diff --git a/wcsmbs/isoc99_vfwscanf.c b/wcsmbs/isoc99_vfwscanf.c
index 7beb45b4d3..f70c6b596d 100644
--- a/wcsmbs/isoc99_vfwscanf.c
+++ b/wcsmbs/isoc99_vfwscanf.c
@@ -28,7 +28,7 @@  __isoc99_vfwscanf (FILE *stream, const wchar_t *format, va_list args)
 
   _IO_acquire_lock_clear_flags2 (stream);
   stream->_flags2 |= _IO_FLAGS2_SCANF_STD;
-  done = _IO_vfwscanf (stream, format, args, NULL);
+  done = __vfwscanf_internal (stream, format, args, 0);
   _IO_release_lock (stream);
   return done;
 }
diff --git a/wcsmbs/isoc99_vswscanf.c b/wcsmbs/isoc99_vswscanf.c
index 130769154d..b91eb651a3 100644
--- a/wcsmbs/isoc99_vswscanf.c
+++ b/wcsmbs/isoc99_vswscanf.c
@@ -24,24 +24,16 @@ 
    This exception applies to code released by its copyright holders
    in files containing the exception.  */
 
-#include <libioP.h>
 #include <wchar.h>
-#include "../libio/strfile.h"
+#include <libio/strfile.h>
 
 int
 __isoc99_vswscanf (const wchar_t *string, const wchar_t *format, va_list args)
 {
-  int ret;
   _IO_strfile sf;
   struct _IO_wide_data wd;
-#ifdef _IO_MTSAFE_IO
-  sf._sbf._f._lock = NULL;
-#endif
-  _IO_no_init (&sf._sbf._f, _IO_USER_LOCK, 0, &wd, &_IO_wstr_jumps);
-  _IO_fwide (&sf._sbf._f, 1);
-  _IO_wstr_init_static (&sf._sbf._f, (wchar_t *)string, 0, NULL);
-  sf._sbf._f._flags2 |= _IO_FLAGS2_SCANF_STD;
-  ret = _IO_vfwscanf ((FILE *) &sf._sbf, format, args, NULL);
-  return ret;
+  FILE *f = _IO_strfile_readw (&sf, &wd, string);
+  f->_flags2 |= _IO_FLAGS2_SCANF_STD;
+  return __vfwscanf_internal (f, format, args, 0);
 }
 libc_hidden_def (__isoc99_vswscanf)
diff --git a/wcsmbs/isoc99_vwscanf.c b/wcsmbs/isoc99_vwscanf.c
index 049521b964..eb22c8acae 100644
--- a/wcsmbs/isoc99_vwscanf.c
+++ b/wcsmbs/isoc99_vwscanf.c
@@ -28,7 +28,7 @@  __isoc99_vwscanf (const wchar_t *format, va_list args)
 
   _IO_acquire_lock_clear_flags2 (stdin);
   stdin->_flags2 |= _IO_FLAGS2_SCANF_STD;
-  done = _IO_vfwscanf (stdin, format, args, NULL);
+  done = __vfwscanf_internal (stdin, format, args, 0);
   _IO_release_lock (stdin);
   return done;
 }
diff --git a/wcsmbs/isoc99_wscanf.c b/wcsmbs/isoc99_wscanf.c
index abfbd50c11..59f80d78fb 100644
--- a/wcsmbs/isoc99_wscanf.c
+++ b/wcsmbs/isoc99_wscanf.c
@@ -33,7 +33,7 @@  __isoc99_wscanf (const wchar_t *format, ...)
   stdin->_flags2 |= _IO_FLAGS2_SCANF_STD;
 
   va_start (arg, format);
-  done = _IO_vfwscanf (stdin, format, arg, NULL);
+  done = __vfwscanf_internal (stdin, format, arg, 0);
   va_end (arg);
 
   _IO_release_lock (stdin);