diff --git a/libio/libio.h b/libio/libio.h
index d4eba2df54..30cb7d784f 100644
--- a/libio/libio.h
+++ b/libio/libio.h
@@ -92,7 +92,6 @@ typedef union
 #define _IO_FLAGS2_NOTCANCEL 2
 #define _IO_FLAGS2_FORTIFY 4
 #define _IO_FLAGS2_USER_WBUF 8
-#define _IO_FLAGS2_SCANF_STD 16
 #define _IO_FLAGS2_NOCLOSE 32
 #define _IO_FLAGS2_CLOEXEC 64
 #define _IO_FLAGS2_NEED_LOCK 128
diff --git a/libio/libioP.h b/libio/libioP.h
index a471c90be8..0772fb1431 100644
--- a/libio/libioP.h
+++ b/libio/libioP.h
@@ -773,7 +773,7 @@ __attribute__ ((__always_inline__))
 _IO_acquire_lock_clear_flags2_fct (FILE **p)
 {
   FILE *fp = *p;
-  fp->_flags2 &= ~(_IO_FLAGS2_FORTIFY | _IO_FLAGS2_SCANF_STD);
+  fp->_flags2 &= ~(_IO_FLAGS2_FORTIFY);
   if ((fp->_flags & _IO_USER_LOCK) == 0)
     _IO_funlockfile (fp);
 }
@@ -787,8 +787,7 @@ _IO_acquire_lock_clear_flags2_fct (FILE **p)
     FILE *_IO_acquire_lock_file = (_fp)
 # define _IO_release_lock(_fp)						      \
     if (_IO_acquire_lock_file != NULL)					      \
-      _IO_acquire_lock_file->_flags2 &= ~(_IO_FLAGS2_FORTIFY		      \
-                                          | _IO_FLAGS2_SCANF_STD);	      \
+      _IO_acquire_lock_file->_flags2 &= ~(_IO_FLAGS2_FORTIFY);		      \
   } while (0)
 #endif
 
diff --git a/stdio-common/isoc99_fscanf.c b/stdio-common/isoc99_fscanf.c
index 4210d11f2b..e788ac47bb 100644
--- a/stdio-common/isoc99_fscanf.c
+++ b/stdio-common/isoc99_fscanf.c
@@ -27,13 +27,9 @@ __isoc99_fscanf (FILE *stream, const char *format, ...)
   va_list arg;
   int done;
 
-  _IO_acquire_lock_clear_flags2 (stream);
-  stream->_flags2 |= _IO_FLAGS2_SCANF_STD;
-
   va_start (arg, format);
-  done = __vfscanf_internal (stream, format, arg, 0);
+  done = __vfscanf_internal (stream, format, arg, SCANF_ISOC99_A);
   va_end (arg);
 
-  _IO_release_lock (stream);
   return done;
 }
diff --git a/stdio-common/isoc99_scanf.c b/stdio-common/isoc99_scanf.c
index 64c873eed9..98b0a19e89 100644
--- a/stdio-common/isoc99_scanf.c
+++ b/stdio-common/isoc99_scanf.c
@@ -19,26 +19,17 @@
 #include <stdio.h>
 #include <libioP.h>
 
-
 /* Read formatted input from stdin according to the format string FORMAT.  */
-/* VARARGS1 */
+
 int
 __isoc99_scanf (const char *format, ...)
 {
   va_list arg;
   int done;
 
-#ifdef _IO_MTSAFE_IO
-  _IO_acquire_lock_clear_flags2 (stdin);
-#endif
-  stdin->_flags2 |= _IO_FLAGS2_SCANF_STD;
-
   va_start (arg, format);
-  done = __vfscanf_internal (stdin, format, arg, 0);
+  done = __vfscanf_internal (stdin, format, arg, SCANF_ISOC99_A);
   va_end (arg);
 
-#ifdef _IO_MTSAFE_IO
-  _IO_release_lock (stdin);
-#endif
   return done;
 }
diff --git a/stdio-common/isoc99_sscanf.c b/stdio-common/isoc99_sscanf.c
index 95b94a68b5..c53130e4ff 100644
--- a/stdio-common/isoc99_sscanf.c
+++ b/stdio-common/isoc99_sscanf.c
@@ -27,10 +27,9 @@ __isoc99_sscanf (const char *s, const char *format, ...)
   int done;
   _IO_strfile sf;
   FILE *f = _IO_strfile_read (&sf, s);
-  f->_flags2 |= _IO_FLAGS2_SCANF_STD;
 
   va_start (arg, format);
-  done = __vfscanf_internal (f, format, arg, 0);
+  done = __vfscanf_internal (f, format, arg, SCANF_ISOC99_A);
   va_end (arg);
 
   return done;
diff --git a/stdio-common/isoc99_vfscanf.c b/stdio-common/isoc99_vfscanf.c
index c96ca831ae..0bc2ad911e 100644
--- a/stdio-common/isoc99_vfscanf.c
+++ b/stdio-common/isoc99_vfscanf.c
@@ -23,12 +23,6 @@
 int
 __isoc99_vfscanf (FILE *stream, const char *format, va_list args)
 {
-  int done;
-
-  _IO_acquire_lock_clear_flags2 (stream);
-  stream->_flags2 |= _IO_FLAGS2_SCANF_STD;
-  done = __vfscanf_internal (stream, format, args, 0);
-  _IO_release_lock (stream);
-  return done;
+  return __vfscanf_internal (stream, format, args, SCANF_ISOC99_A);
 }
 libc_hidden_def (__isoc99_vfscanf)
diff --git a/stdio-common/isoc99_vscanf.c b/stdio-common/isoc99_vscanf.c
index 72ae72ddee..1a270b0e0c 100644
--- a/stdio-common/isoc99_vscanf.c
+++ b/stdio-common/isoc99_vscanf.c
@@ -23,11 +23,5 @@
 int
 __isoc99_vscanf (const char *format, va_list args)
 {
-  int done;
-
-  _IO_acquire_lock_clear_flags2 (stdin);
-  stdin->_flags2 |= _IO_FLAGS2_SCANF_STD;
-  done = __vfscanf_internal (stdin, format, args, 0);
-  _IO_release_lock (stdin);
-  return done;
+  return __vfscanf_internal (stdin, format, args, SCANF_ISOC99_A);
 }
diff --git a/stdio-common/isoc99_vsscanf.c b/stdio-common/isoc99_vsscanf.c
index 02bc0f50e6..dfc394bb51 100644
--- a/stdio-common/isoc99_vsscanf.c
+++ b/stdio-common/isoc99_vsscanf.c
@@ -31,7 +31,6 @@ __isoc99_vsscanf (const char *string, const char *format, va_list args)
 {
   _IO_strfile sf;
   FILE *f = _IO_strfile_read (&sf, string);
-  f->_flags2 |= _IO_FLAGS2_SCANF_STD;
-  return __vfscanf_internal (f, format, args, 0);
+  return __vfscanf_internal (f, format, args, SCANF_ISOC99_A);
 }
 libc_hidden_def (__isoc99_vsscanf)
diff --git a/stdio-common/vfscanf-internal.c b/stdio-common/vfscanf-internal.c
index 93b07ad4bc..9f99d237d2 100644
--- a/stdio-common/vfscanf-internal.c
+++ b/stdio-common/vfscanf-internal.c
@@ -336,8 +336,6 @@ __vfscanf_internal (FILE *s, const char *format, va_list argptr,
   /* 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);
diff --git a/wcsmbs/isoc99_fwscanf.c b/wcsmbs/isoc99_fwscanf.c
index 00b07dd48e..b01826e5ac 100644
--- a/wcsmbs/isoc99_fwscanf.c
+++ b/wcsmbs/isoc99_fwscanf.c
@@ -28,13 +28,9 @@ __isoc99_fwscanf (FILE *stream, const wchar_t *format, ...)
   va_list arg;
   int done;
 
-  _IO_acquire_lock_clear_flags2 (stream);
-  stream->_flags2 |= _IO_FLAGS2_SCANF_STD;
-
   va_start (arg, format);
-  done = __vfwscanf_internal (stream, format, arg, 0);
+  done = __vfwscanf_internal (stream, format, arg, SCANF_ISOC99_A);
   va_end (arg);
 
-  _IO_release_lock (stream);
   return done;
 }
diff --git a/wcsmbs/isoc99_swscanf.c b/wcsmbs/isoc99_swscanf.c
index 40401d0aa1..f90e56d97f 100644
--- a/wcsmbs/isoc99_swscanf.c
+++ b/wcsmbs/isoc99_swscanf.c
@@ -28,10 +28,9 @@ __isoc99_swscanf (const wchar_t *s, const wchar_t *format, ...)
   _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 = __vfwscanf_internal (f, format, arg, 0);
+  done = __vfwscanf_internal (f, format, arg, SCANF_ISOC99_A);
   va_end (arg);
 
   return done;
diff --git a/wcsmbs/isoc99_vfwscanf.c b/wcsmbs/isoc99_vfwscanf.c
index f70c6b596d..f9d0a384f5 100644
--- a/wcsmbs/isoc99_vfwscanf.c
+++ b/wcsmbs/isoc99_vfwscanf.c
@@ -24,12 +24,6 @@
 int
 __isoc99_vfwscanf (FILE *stream, const wchar_t *format, va_list args)
 {
-  int done;
-
-  _IO_acquire_lock_clear_flags2 (stream);
-  stream->_flags2 |= _IO_FLAGS2_SCANF_STD;
-  done = __vfwscanf_internal (stream, format, args, 0);
-  _IO_release_lock (stream);
-  return done;
+  return __vfwscanf_internal (stream, format, args, SCANF_ISOC99_A);
 }
 libc_hidden_def (__isoc99_vfwscanf)
diff --git a/wcsmbs/isoc99_vswscanf.c b/wcsmbs/isoc99_vswscanf.c
index b91eb651a3..0d8ef7611a 100644
--- a/wcsmbs/isoc99_vswscanf.c
+++ b/wcsmbs/isoc99_vswscanf.c
@@ -33,7 +33,6 @@ __isoc99_vswscanf (const wchar_t *string, const wchar_t *format, va_list args)
   _IO_strfile sf;
   struct _IO_wide_data wd;
   FILE *f = _IO_strfile_readw (&sf, &wd, string);
-  f->_flags2 |= _IO_FLAGS2_SCANF_STD;
-  return __vfwscanf_internal (f, format, args, 0);
+  return __vfwscanf_internal (f, format, args, SCANF_ISOC99_A);
 }
 libc_hidden_def (__isoc99_vswscanf)
diff --git a/wcsmbs/isoc99_vwscanf.c b/wcsmbs/isoc99_vwscanf.c
index eb22c8acae..5e4f44d794 100644
--- a/wcsmbs/isoc99_vwscanf.c
+++ b/wcsmbs/isoc99_vwscanf.c
@@ -24,11 +24,5 @@
 int
 __isoc99_vwscanf (const wchar_t *format, va_list args)
 {
-  int done;
-
-  _IO_acquire_lock_clear_flags2 (stdin);
-  stdin->_flags2 |= _IO_FLAGS2_SCANF_STD;
-  done = __vfwscanf_internal (stdin, format, args, 0);
-  _IO_release_lock (stdin);
-  return done;
+  return __vfwscanf_internal (stdin, format, args, SCANF_ISOC99_A);
 }
diff --git a/wcsmbs/isoc99_wscanf.c b/wcsmbs/isoc99_wscanf.c
index 59f80d78fb..a0f24e1f49 100644
--- a/wcsmbs/isoc99_wscanf.c
+++ b/wcsmbs/isoc99_wscanf.c
@@ -29,13 +29,9 @@ __isoc99_wscanf (const wchar_t *format, ...)
   va_list arg;
   int done;
 
-  _IO_acquire_lock_clear_flags2 (stdin);
-  stdin->_flags2 |= _IO_FLAGS2_SCANF_STD;
-
   va_start (arg, format);
-  done = __vfwscanf_internal (stdin, format, arg, 0);
+  done = __vfwscanf_internal (stdin, format, arg, SCANF_ISOC99_A);
   va_end (arg);
 
-  _IO_release_lock (stdin);
   return done;
 }
