*printf-posix: ISO C 23: Add %b directive for binary output of integers.

* lib/printf-parse.c (PRINTF_PARSE): Recognize the 'b' directive.
* lib/printf-parse.h: Update comment.
* lib/wprintf-parse.h: Likewise.
* lib/vasnprintf.c (MAX_ROOM_NEEDED, VASNPRINTF): Add support for the
'b' directive.
* m4/printf.m4 (gl_PRINTF_DIRECTIVE_B): New macro.
* m4/vasnprintf.m4 (gl_PREREQ_VASNPRINTF_DIRECTIVE_B): New macro.
(gl_PREREQ_VASNPRINTF_WITH_EXTRAS): Invoke it.
* m4/vasnwprintf-posix.m4 (gl_FUNC_VASNWPRINTF_POSIX): Invoke
gl_PREREQ_VASNPRINTF_DIRECTIVE_B.
* m4/dprintf-posix.m4 (gl_FUNC_DPRINTF_POSIX): Require
gl_PRINTF_DIRECTIVE_B and test its result. Invoke
gl_PREREQ_VASNPRINTF_DIRECTIVE_B.
* m4/fprintf-posix.m4 (gl_FUNC_FPRINTF_POSIX): Likewise.
* m4/obstack-printf-posix.m4 (gl_FUNC_OBSTACK_PRINTF_POSIX): Likewise.
* m4/snprintf-posix.m4 (gl_FUNC_SNPRINTF_POSIX): Likewise.
* m4/sprintf-posix.m4 (gl_FUNC_SPRINTF_POSIX): Likewise.
* m4/vasnprintf-posix.m4 (gl_FUNC_VASNPRINTF_POSIX): Likewise.
* m4/vasprintf-posix.m4 (gl_FUNC_VASPRINTF_POSIX): Likewise.
* m4/vdprintf-posix.m4 (gl_FUNC_VDPRINTF_POSIX): Likewise.
* m4/vfprintf-posix.m4 (gl_FUNC_VFPRINTF_POSIX): Likewise.
* m4/vsnprintf-posix.m4 (gl_FUNC_VSNPRINTF_POSIX): Likewise.
* m4/vsprintf-posix.m4 (gl_FUNC_VSPRINTF_POSIX): Likewise.
* tests/test-snprintf-posix.h (test_function): Add some tests of the %b
directive.
* tests/test-sprintf-posix.h (test_function): Likewise.
* tests/test-vasnprintf-posix.c (test_function): Likewise.
* tests/test-vasnwprintf-posix.c (test_function): Likewise.
* tests/test-vasprintf-posix.c (test_function): Likewise.
* doc/glibc-functions/asprintf.texi: Mention the 'b' directive.
* doc/glibc-functions/obstack_printf.texi: Likewise.
* doc/glibc-functions/obstack_vprintf.texi: Likewise.
* doc/glibc-functions/vasprintf.texi: Likewise.
* doc/posix-functions/dprintf.texi: Likewise.
* doc/posix-functions/fprintf.texi: Likewise.
* doc/posix-functions/fwprintf.texi: Likewise.
* doc/posix-functions/printf.texi: Likewise.
* doc/posix-functions/snprintf.texi: Likewise.
* doc/posix-functions/sprintf.texi: Likewise.
* doc/posix-functions/swprintf.texi: Likewise.
* doc/posix-functions/vdprintf.texi: Likewise.
* doc/posix-functions/vfprintf.texi: Likewise.
* doc/posix-functions/vfwprintf.texi: Likewise.
* doc/posix-functions/vprintf.texi: Likewise.
* doc/posix-functions/vsnprintf.texi: Likewise.
* doc/posix-functions/vsprintf.texi: Likewise.
* doc/posix-functions/vswprintf.texi: Likewise.
* doc/posix-functions/vwprintf.texi: Likewise.
* doc/posix-functions/wprintf.texi: Likewise.

14 files changed, 358 insertions, 229 deletions

diff --git a/m4/dprintf-posix.m4 b/m4/dprintf-posix.m4
index a25ef4164e..4186ab70fe 100644
--- a/m4/dprintf-posix.m4
+++ b/m4/dprintf-posix.m4
@@ -1,4 +1,4 @@
-# dprintf-posix.m4 serial 3
+# dprintf-posix.m4 serial 4
 dnl Copyright (C) 2007-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -11,6 +11,7 @@ AC_DEFUN([gl_FUNC_DPRINTF_POSIX],
   AC_REQUIRE([gl_PRINTF_INFINITE])
   AC_REQUIRE([gl_PRINTF_INFINITE_LONG_DOUBLE])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_A])
+  AC_REQUIRE([gl_PRINTF_DIRECTIVE_B])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_F])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_N])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_LS])
@@ -33,27 +34,31 @@ AC_DEFUN([gl_FUNC_DPRINTF_POSIX],
                   *yes)
                     case "$gl_cv_func_printf_directive_a" in
                       *yes)
-                        case "$gl_cv_func_printf_directive_f" in
+                        case "$gl_cv_func_printf_directive_b" in
                           *yes)
-                            case "$gl_cv_func_printf_directive_n" in
+                            case "$gl_cv_func_printf_directive_f" in
                               *yes)
-                                case "$gl_cv_func_printf_directive_ls" in
+                                case "$gl_cv_func_printf_directive_n" in
                                   *yes)
-                                    case "$gl_cv_func_printf_positions" in
+                                    case "$gl_cv_func_printf_directive_ls" in
                                       *yes)
-                                        case "$gl_cv_func_printf_flag_grouping" in
+                                        case "$gl_cv_func_printf_positions" in
                                           *yes)
-                                            case "$gl_cv_func_printf_flag_leftadjust" in
+                                            case "$gl_cv_func_printf_flag_grouping" in
                                               *yes)
-                                                case "$gl_cv_func_printf_flag_zero" in
+                                                case "$gl_cv_func_printf_flag_leftadjust" in
                                                   *yes)
-                                                    case "$gl_cv_func_printf_precision" in
+                                                    case "$gl_cv_func_printf_flag_zero" in
                                                       *yes)
-                                                        case "$gl_cv_func_printf_enomem" in
+                                                        case "$gl_cv_func_printf_precision" in
                                                           *yes)
-                                                            # dprintf exists and is
-                                                            # already POSIX compliant.
-                                                            gl_cv_func_dprintf_posix=yes
+                                                            case "$gl_cv_func_printf_enomem" in
+                                                              *yes)
+                                                                # dprintf exists and is
+                                                                # already POSIX compliant.
+                                                                gl_cv_func_dprintf_posix=yes
+                                                                ;;
+                                                            esac
                                                             ;;
                                                         esac
                                                         ;;
@@ -88,6 +93,7 @@ AC_DEFUN([gl_FUNC_DPRINTF_POSIX],
     gl_PREREQ_VASNPRINTF_INFINITE_DOUBLE
     gl_PREREQ_VASNPRINTF_INFINITE_LONG_DOUBLE
     gl_PREREQ_VASNPRINTF_DIRECTIVE_A
+    gl_PREREQ_VASNPRINTF_DIRECTIVE_B
     gl_PREREQ_VASNPRINTF_DIRECTIVE_F
     gl_PREREQ_VASNPRINTF_DIRECTIVE_LS
     gl_PREREQ_VASNPRINTF_FLAG_GROUPING
diff --git a/m4/fprintf-posix.m4 b/m4/fprintf-posix.m4
index 3a51bcf4e1..5602000e4a 100644
--- a/m4/fprintf-posix.m4
+++ b/m4/fprintf-posix.m4
@@ -1,4 +1,4 @@
-# fprintf-posix.m4 serial 14
+# fprintf-posix.m4 serial 15
 dnl Copyright (C) 2007-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -11,6 +11,7 @@ AC_DEFUN([gl_FUNC_FPRINTF_POSIX],
   AC_REQUIRE([gl_PRINTF_INFINITE])
   AC_REQUIRE([gl_PRINTF_INFINITE_LONG_DOUBLE])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_A])
+  AC_REQUIRE([gl_PRINTF_DIRECTIVE_B])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_F])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_N])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_LS])
@@ -31,27 +32,31 @@ AC_DEFUN([gl_FUNC_FPRINTF_POSIX],
                 *yes)
                   case "$gl_cv_func_printf_directive_a" in
                     *yes)
-                      case "$gl_cv_func_printf_directive_f" in
+                      case "$gl_cv_func_printf_directive_b" in
                         *yes)
-                          case "$gl_cv_func_printf_directive_n" in
+                          case "$gl_cv_func_printf_directive_f" in
                             *yes)
-                              case "$gl_cv_func_printf_directive_ls" in
+                              case "$gl_cv_func_printf_directive_n" in
                                 *yes)
-                                  case "$gl_cv_func_printf_positions" in
+                                  case "$gl_cv_func_printf_directive_ls" in
                                     *yes)
-                                      case "$gl_cv_func_printf_flag_grouping" in
+                                      case "$gl_cv_func_printf_positions" in
                                         *yes)
-                                          case "$gl_cv_func_printf_flag_leftadjust" in
+                                          case "$gl_cv_func_printf_flag_grouping" in
                                             *yes)
-                                              case "$gl_cv_func_printf_flag_zero" in
+                                              case "$gl_cv_func_printf_flag_leftadjust" in
                                                 *yes)
-                                                  case "$gl_cv_func_printf_precision" in
+                                                  case "$gl_cv_func_printf_flag_zero" in
                                                     *yes)
-                                                      case "$gl_cv_func_printf_enomem" in
+                                                      case "$gl_cv_func_printf_precision" in
                                                         *yes)
-                                                          # fprintf exists and is
-                                                          # already POSIX compliant.
-                                                          gl_cv_func_fprintf_posix=yes
+                                                          case "$gl_cv_func_printf_enomem" in
+                                                            *yes)
+                                                              # fprintf exists and is
+                                                              # already POSIX compliant.
+                                                              gl_cv_func_fprintf_posix=yes
+                                                              ;;
+                                                          esac
                                                           ;;
                                                       esac
                                                       ;;
@@ -85,6 +90,7 @@ AC_DEFUN([gl_FUNC_FPRINTF_POSIX],
     gl_PREREQ_VASNPRINTF_INFINITE_DOUBLE
     gl_PREREQ_VASNPRINTF_INFINITE_LONG_DOUBLE
     gl_PREREQ_VASNPRINTF_DIRECTIVE_A
+    gl_PREREQ_VASNPRINTF_DIRECTIVE_B
     gl_PREREQ_VASNPRINTF_DIRECTIVE_F
     gl_PREREQ_VASNPRINTF_DIRECTIVE_LS
     gl_PREREQ_VASNPRINTF_FLAG_GROUPING
diff --git a/m4/obstack-printf-posix.m4 b/m4/obstack-printf-posix.m4
index 10f744c575..633b017442 100644
--- a/m4/obstack-printf-posix.m4
+++ b/m4/obstack-printf-posix.m4
@@ -1,4 +1,4 @@
-# obstack-printf-posix.m4 serial 4
+# obstack-printf-posix.m4 serial 5
 dnl Copyright (C) 2008-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -14,6 +14,7 @@ AC_DEFUN([gl_FUNC_OBSTACK_PRINTF_POSIX],
   AC_REQUIRE([gl_PRINTF_INFINITE])
   AC_REQUIRE([gl_PRINTF_INFINITE_LONG_DOUBLE])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_A])
+  AC_REQUIRE([gl_PRINTF_DIRECTIVE_B])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_F])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_N])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_LS])
@@ -36,27 +37,31 @@ AC_DEFUN([gl_FUNC_OBSTACK_PRINTF_POSIX],
                   *yes)
                     case "$gl_cv_func_printf_directive_a" in
                       *yes)
-                        case "$gl_cv_func_printf_directive_f" in
+                        case "$gl_cv_func_printf_directive_b" in
                           *yes)
-                            case "$gl_cv_func_printf_directive_n" in
+                            case "$gl_cv_func_printf_directive_f" in
                               *yes)
-                                case "$gl_cv_func_printf_directive_ls" in
+                                case "$gl_cv_func_printf_directive_n" in
                                   *yes)
-                                    case "$gl_cv_func_printf_positions" in
+                                    case "$gl_cv_func_printf_directive_ls" in
                                       *yes)
-                                        case "$gl_cv_func_printf_flag_grouping" in
+                                        case "$gl_cv_func_printf_positions" in
                                           *yes)
-                                            case "$gl_cv_func_printf_flag_leftadjust" in
+                                            case "$gl_cv_func_printf_flag_grouping" in
                                               *yes)
-                                                case "$gl_cv_func_printf_flag_zero" in
+                                                case "$gl_cv_func_printf_flag_leftadjust" in
                                                   *yes)
-                                                    case "$gl_cv_func_printf_precision" in
+                                                    case "$gl_cv_func_printf_flag_zero" in
                                                       *yes)
-                                                        case "$gl_cv_func_printf_enomem" in
+                                                        case "$gl_cv_func_printf_precision" in
                                                           *yes)
-                                                            # obstack_printf exists and is
-                                                            # already POSIX compliant.
-                                                            gl_cv_func_obstack_printf_posix=yes
+                                                            case "$gl_cv_func_printf_enomem" in
+                                                              *yes)
+                                                                # obstack_printf exists and is
+                                                                # already POSIX compliant.
+                                                                gl_cv_func_obstack_printf_posix=yes
+                                                                ;;
+                                                            esac
                                                             ;;
                                                         esac
                                                         ;;
@@ -91,6 +96,7 @@ AC_DEFUN([gl_FUNC_OBSTACK_PRINTF_POSIX],
     gl_PREREQ_VASNPRINTF_INFINITE_DOUBLE
     gl_PREREQ_VASNPRINTF_INFINITE_LONG_DOUBLE
     gl_PREREQ_VASNPRINTF_DIRECTIVE_A
+    gl_PREREQ_VASNPRINTF_DIRECTIVE_B
     gl_PREREQ_VASNPRINTF_DIRECTIVE_F
     gl_PREREQ_VASNPRINTF_DIRECTIVE_LS
     gl_PREREQ_VASNPRINTF_FLAG_GROUPING
diff --git a/m4/printf.m4 b/m4/printf.m4
index de98a870e9..719679c362 100644
--- a/m4/printf.m4
+++ b/m4/printf.m4
@@ -1,4 +1,4 @@
-# printf.m4 serial 74
+# printf.m4 serial 75
 dnl Copyright (C) 2003, 2007-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -603,6 +603,50 @@ int main ()
     ])
 ])
 
+dnl Test whether the *printf family of functions supports the 'b' conversion
+dnl specifier for binary output of integers.
+dnl (ISO C23)
+dnl Result is gl_cv_func_printf_directive_b.
+
+AC_DEFUN([gl_PRINTF_DIRECTIVE_B],
+[
+  AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([whether printf supports the 'b' directive],
+    [gl_cv_func_printf_directive_b],
+    [
+      AC_RUN_IFELSE(
+        [AC_LANG_SOURCE([[
+#include <stdio.h>
+#include <string.h>
+static char buf[100];
+int main ()
+{
+  int result = 0;
+  if (sprintf (buf, "%b %d", 12345, 33, 44, 55) < 0
+      || strcmp (buf, "11000000111001 33") != 0)
+    result |= 1;
+  return result;
+}]])],
+        [gl_cv_func_printf_directive_b=yes],
+        [gl_cv_func_printf_directive_b=no],
+        [
+         case "$host_os" in
+                               # Guess no on glibc systems.
+           *-gnu* | gnu*)      gl_cv_func_printf_directive_b="guessing no";;
+                               # Guess no on musl systems.
+           *-musl* | midipix*) gl_cv_func_printf_directive_b="guessing no";;
+                               # Guess no on Android.
+           linux*-android*)    gl_cv_func_printf_directive_b="guessing no";;
+                               # Guess no on native Windows.
+           mingw*)             gl_cv_func_printf_directive_b="guessing no";;
+                               # If we don't know, obey --enable-cross-guesses.
+           *)                  gl_cv_func_printf_directive_b="$gl_cross_guess_normal";;
+         esac
+        ])
+    ])
+])
+
 dnl Test whether the *printf family of functions supports the %F format
 dnl directive. (ISO C99, POSIX:2001)
 dnl Result is gl_cv_func_printf_directive_f.
@@ -1648,81 +1692,83 @@ dnl 2 = gl_PRINTF_LONG_DOUBLE
 dnl 3 = gl_PRINTF_INFINITE
 dnl 4 = gl_PRINTF_INFINITE_LONG_DOUBLE
 dnl 5 = gl_PRINTF_DIRECTIVE_A
-dnl 6 = gl_PRINTF_DIRECTIVE_F
-dnl 7 = gl_PRINTF_DIRECTIVE_N
-dnl 8 = gl_PRINTF_DIRECTIVE_LS
-dnl 9 = gl_PRINTF_POSITIONS
-dnl 10 = gl_PRINTF_FLAG_GROUPING
-dnl 11 = gl_PRINTF_FLAG_LEFTADJUST
-dnl 12 = gl_PRINTF_FLAG_ZERO
-dnl 13 = gl_PRINTF_PRECISION
-dnl 14 = gl_PRINTF_ENOMEM
-dnl 15 = gl_SNPRINTF_PRESENCE
-dnl 16 = gl_SNPRINTF_TRUNCATION_C99
-dnl 17 = gl_SNPRINTF_RETVAL_C99
-dnl 18 = gl_SNPRINTF_DIRECTIVE_N
-dnl 19 = gl_SNPRINTF_SIZE1
-dnl 20 = gl_VSNPRINTF_ZEROSIZE_C99
+dnl 6 = gl_PRINTF_DIRECTIVE_B
+dnl 7 = gl_PRINTF_DIRECTIVE_F
+dnl 8 = gl_PRINTF_DIRECTIVE_N
+dnl 9 = gl_PRINTF_DIRECTIVE_LS
+dnl 10 = gl_PRINTF_POSITIONS
+dnl 11 = gl_PRINTF_FLAG_GROUPING
+dnl 12 = gl_PRINTF_FLAG_LEFTADJUST
+dnl 13 = gl_PRINTF_FLAG_ZERO
+dnl 14 = gl_PRINTF_PRECISION
+dnl 15 = gl_PRINTF_ENOMEM
+dnl 16 = gl_SNPRINTF_PRESENCE
+dnl 17 = gl_SNPRINTF_TRUNCATION_C99
+dnl 18 = gl_SNPRINTF_RETVAL_C99
+dnl 19 = gl_SNPRINTF_DIRECTIVE_N
+dnl 20 = gl_SNPRINTF_SIZE1
+dnl 21 = gl_VSNPRINTF_ZEROSIZE_C99
 dnl
 dnl 1 = checking whether printf supports size specifiers as in C99...
 dnl 2 = checking whether printf supports 'long double' arguments...
 dnl 3 = checking whether printf supports infinite 'double' arguments...
 dnl 4 = checking whether printf supports infinite 'long double' arguments...
 dnl 5 = checking whether printf supports the 'a' and 'A' directives...
-dnl 6 = checking whether printf supports the 'F' directive...
-dnl 7 = checking whether printf supports the 'n' directive...
-dnl 8 = checking whether printf supports the 'ls' directive...
-dnl 9 = checking whether printf supports POSIX/XSI format strings with positions...
-dnl 10 = checking whether printf supports the grouping flag...
-dnl 11 = checking whether printf supports the left-adjust flag correctly...
-dnl 12 = checking whether printf supports the zero flag correctly...
-dnl 13 = checking whether printf supports large precisions...
-dnl 14 = checking whether printf survives out-of-memory conditions...
-dnl 15 = checking for snprintf...
-dnl 16 = checking whether snprintf truncates the result as in C99...
-dnl 17 = checking whether snprintf returns a byte count as in C99...
-dnl 18 = checking whether snprintf fully supports the 'n' directive...
-dnl 19 = checking whether snprintf respects a size of 1...
-dnl 20 = checking whether vsnprintf respects a zero size as in C99...
+dnl 6 = checking whether printf supports the 'b' directive...
+dnl 7 = checking whether printf supports the 'F' directive...
+dnl 8 = checking whether printf supports the 'n' directive...
+dnl 9 = checking whether printf supports the 'ls' directive...
+dnl 10 = checking whether printf supports POSIX/XSI format strings with positions...
+dnl 11 = checking whether printf supports the grouping flag...
+dnl 12 = checking whether printf supports the left-adjust flag correctly...
+dnl 13 = checking whether printf supports the zero flag correctly...
+dnl 14 = checking whether printf supports large precisions...
+dnl 15 = checking whether printf survives out-of-memory conditions...
+dnl 16 = checking for snprintf...
+dnl 17 = checking whether snprintf truncates the result as in C99...
+dnl 18 = checking whether snprintf returns a byte count as in C99...
+dnl 19 = checking whether snprintf fully supports the 'n' directive...
+dnl 20 = checking whether snprintf respects a size of 1...
+dnl 21 = checking whether vsnprintf respects a zero size as in C99...
 dnl
 dnl . = yes, # = no.
 dnl
-dnl                                  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20
-dnl   glibc 2.5                      .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .
-dnl   glibc 2.3.6                    .  .  .  .  #  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .
-dnl   FreeBSD 13.0                   .  .  .  .  #  .  .  .  .  .  .  .  .  #  .  .  .  .  .  .
-dnl   FreeBSD 5.4, 6.1               .  .  .  .  #  .  .  .  .  .  .  #  .  #  .  .  .  .  .  .
-dnl   Mac OS X 10.13.5               .  .  .  #  #  .  #  .  .  .  .  .  .  .  .  .  .  #  .  .
-dnl   Mac OS X 10.5.8                .  .  .  #  #  .  .  .  .  .  .  #  .  .  .  .  .  .  .  .
-dnl   Mac OS X 10.3.9                .  .  .  .  #  .  .  .  .  .  .  #  .  #  .  .  .  .  .  .
-dnl   OpenBSD 6.0, 6.7               .  .  .  .  #  .  .  .  .  .  .  .  .  #  .  .  .  .  .  .
-dnl   OpenBSD 3.9, 4.0               .  .  #  #  #  #  .  #  .  #  .  #  .  #  .  .  .  .  .  .
-dnl   Cygwin 1.7.0 (2009)            .  .  .  #  .  .  .  ?  .  .  .  .  .  ?  .  .  .  .  .  .
-dnl   Cygwin 1.5.25 (2008)           .  .  .  #  #  .  .  #  .  .  .  .  .  #  .  .  .  .  .  .
-dnl   Cygwin 1.5.19 (2006)           #  .  .  #  #  #  .  #  .  #  .  #  #  #  .  .  .  .  .  .
-dnl   Solaris 11.4                   .  .  #  #  #  .  .  #  .  .  .  #  .  .  .  .  .  .  .  .
-dnl   Solaris 11.3                   .  .  .  .  #  .  .  #  .  .  .  .  .  .  .  .  .  .  .  .
-dnl   Solaris 11.0                   .  .  #  #  #  .  .  #  .  .  .  #  .  .  .  .  .  .  .  .
-dnl   Solaris 10                     .  .  #  #  #  .  .  #  .  .  .  #  #  .  .  .  .  .  .  .
-dnl   Solaris 2.6 ... 9              #  .  #  #  #  #  .  #  .  .  .  #  #  .  .  .  #  .  .  .
-dnl   Solaris 2.5.1                  #  .  #  #  #  #  .  #  .  .  .  #  .  .  #  #  #  #  #  #
-dnl   AIX 7.1                        .  .  #  #  #  .  .  .  .  .  .  #  #  .  .  .  .  .  .  .
-dnl   AIX 5.2                        .  .  #  #  #  .  .  .  .  .  .  #  .  .  .  .  .  .  .  .
-dnl   AIX 4.3.2, 5.1                 #  .  #  #  #  #  .  .  .  .  .  #  .  .  .  .  #  .  .  .
-dnl   HP-UX 11.31                    .  .  .  .  #  .  .  .  .  .  .  #  .  .  .  .  #  #  .  .
-dnl   HP-UX 11.{00,11,23}            #  .  .  .  #  #  .  .  .  .  .  #  .  .  .  .  #  #  .  #
-dnl   HP-UX 10.20                    #  .  #  .  #  #  .  ?  .  .  #  #  .  .  .  .  #  #  ?  #
-dnl   IRIX 6.5                       #  .  #  #  #  #  .  #  .  .  .  #  .  .  .  .  #  .  .  .
-dnl   OSF/1 5.1                      #  .  #  #  #  #  .  .  .  .  .  #  .  .  .  .  #  .  .  #
-dnl   OSF/1 4.0d                     #  .  #  #  #  #  .  .  .  .  .  #  .  .  #  #  #  #  #  #
-dnl   NetBSD 9.0                     .  .  .  .  #  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .
-dnl   NetBSD 5.0                     .  .  .  #  #  .  .  .  .  .  .  #  .  #  .  .  .  .  .  .
-dnl   NetBSD 4.0                     .  ?  ?  ?  ?  ?  .  ?  .  ?  ?  ?  ?  ?  .  .  .  ?  ?  ?
-dnl   NetBSD 3.0                     .  .  .  .  #  #  .  ?  #  #  ?  #  .  #  .  .  .  .  .  .
-dnl   Haiku                          .  .  .  #  #  #  .  #  .  .  .  .  .  ?  .  .  ?  .  .  .
-dnl   BeOS                           #  #  .  #  #  #  .  ?  #  .  ?  .  #  ?  .  .  ?  .  .  .
-dnl   Android 4.3                    .  .  #  #  #  #  #  #  .  #  .  #  .  #  .  .  .  #  .  .
-dnl   old mingw / msvcrt             #  #  #  #  #  #  .  .  #  #  .  #  #  ?  .  #  #  #  .  .
-dnl   MSVC 9                         #  #  #  #  #  #  #  .  #  #  .  #  #  ?  #  #  #  #  .  .
-dnl   mingw 2009-2011                .  #  .  #  .  .  .  .  #  #  .  .  .  ?  .  .  .  .  .  .
-dnl   mingw-w64 2011                 #  #  #  #  #  #  .  .  #  #  .  #  #  ?  .  #  #  #  .  .
+dnl                                  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20 21
+dnl   glibc 2.5                      .  .  .  .  .  #  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .
+dnl   glibc 2.3.6                    .  .  .  .  #  #  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .
+dnl   FreeBSD 13.0                   .  .  .  .  #  #  .  .  .  .  .  .  .  .  #  .  .  .  .  .  .
+dnl   FreeBSD 5.4, 6.1               .  .  .  .  #  #  .  .  .  .  .  .  #  .  #  .  .  .  .  .  .
+dnl   Mac OS X 10.13.5               .  .  .  #  #  #  .  #  .  .  .  .  .  .  .  .  .  .  #  .  .
+dnl   Mac OS X 10.5.8                .  .  .  #  #  #  .  .  .  .  .  .  #  .  .  .  .  .  .  .  .
+dnl   Mac OS X 10.3.9                .  .  .  .  #  #  .  .  .  .  .  .  #  .  #  .  .  .  .  .  .
+dnl   OpenBSD 6.0, 6.7               .  .  .  .  #  #  .  .  .  .  .  .  .  .  #  .  .  .  .  .  .
+dnl   OpenBSD 3.9, 4.0               .  .  #  #  #  #  #  .  #  .  #  .  #  .  #  .  .  .  .  .  .
+dnl   Cygwin 1.7.0 (2009)            .  .  .  #  .  #  .  .  ?  .  .  .  .  .  ?  .  .  .  .  .  .
+dnl   Cygwin 1.5.25 (2008)           .  .  .  #  #  #  .  .  #  .  .  .  .  .  #  .  .  .  .  .  .
+dnl   Cygwin 1.5.19 (2006)           #  .  .  #  #  #  #  .  #  .  #  .  #  #  #  .  .  .  .  .  .
+dnl   Solaris 11.4                   .  .  #  #  #  #  .  .  #  .  .  .  #  .  .  .  .  .  .  .  .
+dnl   Solaris 11.3                   .  .  .  .  #  #  .  .  #  .  .  .  .  .  .  .  .  .  .  .  .
+dnl   Solaris 11.0                   .  .  #  #  #  #  .  .  #  .  .  .  #  .  .  .  .  .  .  .  .
+dnl   Solaris 10                     .  .  #  #  #  #  .  .  #  .  .  .  #  #  .  .  .  .  .  .  .
+dnl   Solaris 2.6 ... 9              #  .  #  #  #  #  #  .  #  .  .  .  #  #  .  .  .  #  .  .  .
+dnl   Solaris 2.5.1                  #  .  #  #  #  #  #  .  #  .  .  .  #  .  .  #  #  #  #  #  #
+dnl   AIX 7.1                        .  .  #  #  #  #  .  .  .  .  .  .  #  #  .  .  .  .  .  .  .
+dnl   AIX 5.2                        .  .  #  #  #  #  .  .  .  .  .  .  #  .  .  .  .  .  .  .  .
+dnl   AIX 4.3.2, 5.1                 #  .  #  #  #  #  #  .  .  .  .  .  #  .  .  .  .  #  .  .  .
+dnl   HP-UX 11.31                    .  .  .  .  #  #  .  .  .  .  .  .  #  .  .  .  .  #  #  .  .
+dnl   HP-UX 11.{00,11,23}            #  .  .  .  #  #  #  .  .  .  .  .  #  .  .  .  .  #  #  .  #
+dnl   HP-UX 10.20                    #  .  #  .  #  #  #  .  ?  .  .  #  #  .  .  .  .  #  #  ?  #
+dnl   IRIX 6.5                       #  .  #  #  #  #  #  .  #  .  .  .  #  .  .  .  .  #  .  .  .
+dnl   OSF/1 5.1                      #  .  #  #  #  #  #  .  .  .  .  .  #  .  .  .  .  #  .  .  #
+dnl   OSF/1 4.0d                     #  .  #  #  #  #  #  .  .  .  .  .  #  .  .  #  #  #  #  #  #
+dnl   NetBSD 9.0                     .  .  .  .  #  #  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .
+dnl   NetBSD 5.0                     .  .  .  #  #  #  .  .  .  .  .  .  #  .  #  .  .  .  .  .  .
+dnl   NetBSD 4.0                     .  ?  ?  ?  ?  #  ?  .  ?  .  ?  ?  ?  ?  ?  .  .  .  ?  ?  ?
+dnl   NetBSD 3.0                     .  .  .  .  #  #  #  .  ?  #  #  ?  #  .  #  .  .  .  .  .  .
+dnl   Haiku                          .  .  .  #  #  #  #  .  #  .  .  .  .  .  ?  .  .  ?  .  .  .
+dnl   BeOS                           #  #  .  #  #  #  #  .  ?  #  .  ?  .  #  ?  .  .  ?  .  .  .
+dnl   Android 4.3                    .  .  #  #  #  #  #  #  #  .  #  .  #  .  #  .  .  .  #  .  .
+dnl   old mingw / msvcrt             #  #  #  #  #  #  #  .  .  #  #  .  #  #  ?  .  #  #  #  .  .
+dnl   MSVC 9                         #  #  #  #  #  #  #  #  .  #  #  .  #  #  ?  #  #  #  #  .  .
+dnl   mingw 2009-2011                .  #  .  #  .  #  .  .  .  #  #  .  .  .  ?  .  .  .  .  .  .
+dnl   mingw-w64 2011                 #  #  #  #  #  #  #  .  .  #  #  .  #  #  ?  .  #  #  #  .  .
diff --git a/m4/snprintf-posix.m4 b/m4/snprintf-posix.m4
index 61a80a8aa8..033e1916e5 100644
--- a/m4/snprintf-posix.m4
+++ b/m4/snprintf-posix.m4
@@ -1,4 +1,4 @@
-# snprintf-posix.m4 serial 14
+# snprintf-posix.m4 serial 15
 dnl Copyright (C) 2007-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -11,6 +11,7 @@ AC_DEFUN([gl_FUNC_SNPRINTF_POSIX],
   AC_REQUIRE([gl_PRINTF_INFINITE])
   AC_REQUIRE([gl_PRINTF_INFINITE_LONG_DOUBLE])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_A])
+  AC_REQUIRE([gl_PRINTF_DIRECTIVE_B])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_F])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_N])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_LS])
@@ -38,37 +39,41 @@ AC_DEFUN([gl_FUNC_SNPRINTF_POSIX],
                   *yes)
                     case "$gl_cv_func_printf_directive_a" in
                       *yes)
-                        case "$gl_cv_func_printf_directive_f" in
+                        case "$gl_cv_func_printf_directive_b" in
                           *yes)
-                            case "$gl_cv_func_printf_directive_n" in
+                            case "$gl_cv_func_printf_directive_f" in
                               *yes)
-                                case "$gl_cv_func_printf_directive_ls" in
+                                case "$gl_cv_func_printf_directive_n" in
                                   *yes)
-                                    case "$gl_cv_func_printf_positions" in
+                                    case "$gl_cv_func_printf_directive_ls" in
                                       *yes)
-                                        case "$gl_cv_func_printf_flag_grouping" in
+                                        case "$gl_cv_func_printf_positions" in
                                           *yes)
-                                            case "$gl_cv_func_printf_flag_leftadjust" in
+                                            case "$gl_cv_func_printf_flag_grouping" in
                                               *yes)
-                                                case "$gl_cv_func_printf_flag_zero" in
+                                                case "$gl_cv_func_printf_flag_leftadjust" in
                                                   *yes)
-                                                    case "$gl_cv_func_printf_precision" in
+                                                    case "$gl_cv_func_printf_flag_zero" in
                                                       *yes)
-                                                        case "$gl_cv_func_printf_enomem" in
+                                                        case "$gl_cv_func_printf_precision" in
                                                           *yes)
-                                                            case "$gl_cv_func_snprintf_truncation_c99" in
+                                                            case "$gl_cv_func_printf_enomem" in
                                                               *yes)
-                                                                case "$gl_cv_func_snprintf_retval_c99" in
+                                                                case "$gl_cv_func_snprintf_truncation_c99" in
                                                                   *yes)
-                                                                    case "$gl_cv_func_snprintf_directive_n" in
+                                                                    case "$gl_cv_func_snprintf_retval_c99" in
                                                                       *yes)
-                                                                        case "$gl_cv_func_snprintf_size1" in
+                                                                        case "$gl_cv_func_snprintf_directive_n" in
                                                                           *yes)
-                                                                            case "$gl_cv_func_vsnprintf_zerosize_c99" in
+                                                                            case "$gl_cv_func_snprintf_size1" in
                                                                               *yes)
-                                                                                # snprintf exists and is
-                                                                                # already POSIX compliant.
-                                                                                gl_cv_func_snprintf_posix=yes
+                                                                                case "$gl_cv_func_vsnprintf_zerosize_c99" in
+                                                                                  *yes)
+                                                                                    # snprintf exists and is
+                                                                                    # already POSIX compliant.
+                                                                                    gl_cv_func_snprintf_posix=yes
+                                                                                    ;;
+                                                                                esac
                                                                                 ;;
                                                                             esac
                                                                             ;;
@@ -113,6 +118,7 @@ AC_DEFUN([gl_FUNC_SNPRINTF_POSIX],
     gl_PREREQ_VASNPRINTF_INFINITE_DOUBLE
     gl_PREREQ_VASNPRINTF_INFINITE_LONG_DOUBLE
     gl_PREREQ_VASNPRINTF_DIRECTIVE_A
+    gl_PREREQ_VASNPRINTF_DIRECTIVE_B
     gl_PREREQ_VASNPRINTF_DIRECTIVE_F
     gl_PREREQ_VASNPRINTF_DIRECTIVE_LS
     gl_PREREQ_VASNPRINTF_FLAG_GROUPING
diff --git a/m4/sprintf-posix.m4 b/m4/sprintf-posix.m4
index 9d9258e17a..cfcbe37cce 100644
--- a/m4/sprintf-posix.m4
+++ b/m4/sprintf-posix.m4
@@ -1,4 +1,4 @@
-# sprintf-posix.m4 serial 12
+# sprintf-posix.m4 serial 13
 dnl Copyright (C) 2007-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -11,6 +11,7 @@ AC_DEFUN([gl_FUNC_SPRINTF_POSIX],
   AC_REQUIRE([gl_PRINTF_INFINITE])
   AC_REQUIRE([gl_PRINTF_INFINITE_LONG_DOUBLE])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_A])
+  AC_REQUIRE([gl_PRINTF_DIRECTIVE_B])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_F])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_N])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_LS])
@@ -31,27 +32,31 @@ AC_DEFUN([gl_FUNC_SPRINTF_POSIX],
                 *yes)
                   case "$gl_cv_func_printf_directive_a" in
                     *yes)
-                      case "$gl_cv_func_printf_directive_f" in
+                      case "$gl_cv_func_printf_directive_b" in
                         *yes)
-                          case "$gl_cv_func_printf_directive_n" in
+                          case "$gl_cv_func_printf_directive_f" in
                             *yes)
-                              case "$gl_cv_func_printf_directive_ls" in
+                              case "$gl_cv_func_printf_directive_n" in
                                 *yes)
-                                  case "$gl_cv_func_printf_positions" in
+                                  case "$gl_cv_func_printf_directive_ls" in
                                     *yes)
-                                      case "$gl_cv_func_printf_flag_grouping" in
+                                      case "$gl_cv_func_printf_positions" in
                                         *yes)
-                                          case "$gl_cv_func_printf_flag_leftadjust" in
+                                          case "$gl_cv_func_printf_flag_grouping" in
                                             *yes)
-                                              case "$gl_cv_func_printf_flag_zero" in
+                                              case "$gl_cv_func_printf_flag_leftadjust" in
                                                 *yes)
-                                                  case "$gl_cv_func_printf_precision" in
+                                                  case "$gl_cv_func_printf_flag_zero" in
                                                     *yes)
-                                                      case "$gl_cv_func_printf_enomem" in
+                                                      case "$gl_cv_func_printf_precision" in
                                                         *yes)
-                                                          # sprintf exists and is
-                                                          # already POSIX compliant.
-                                                          gl_cv_func_sprintf_posix=yes
+                                                          case "$gl_cv_func_printf_enomem" in
+                                                            *yes)
+                                                              # sprintf exists and is
+                                                              # already POSIX compliant.
+                                                              gl_cv_func_sprintf_posix=yes
+                                                              ;;
+                                                          esac
                                                           ;;
                                                       esac
                                                       ;;
@@ -85,6 +90,7 @@ AC_DEFUN([gl_FUNC_SPRINTF_POSIX],
     gl_PREREQ_VASNPRINTF_INFINITE_DOUBLE
     gl_PREREQ_VASNPRINTF_INFINITE_LONG_DOUBLE
     gl_PREREQ_VASNPRINTF_DIRECTIVE_A
+    gl_PREREQ_VASNPRINTF_DIRECTIVE_B
     gl_PREREQ_VASNPRINTF_DIRECTIVE_F
     gl_PREREQ_VASNPRINTF_DIRECTIVE_LS
     gl_PREREQ_VASNPRINTF_FLAG_GROUPING
diff --git a/m4/vasnprintf-posix.m4 b/m4/vasnprintf-posix.m4
index baf7cb437d..4983dfc50a 100644
--- a/m4/vasnprintf-posix.m4
+++ b/m4/vasnprintf-posix.m4
@@ -1,4 +1,4 @@
-# vasnprintf-posix.m4 serial 13
+# vasnprintf-posix.m4 serial 14
 dnl Copyright (C) 2007-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -11,6 +11,7 @@ AC_DEFUN([gl_FUNC_VASNPRINTF_POSIX],
   AC_REQUIRE([gl_PRINTF_INFINITE])
   AC_REQUIRE([gl_PRINTF_INFINITE_LONG_DOUBLE])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_A])
+  AC_REQUIRE([gl_PRINTF_DIRECTIVE_B])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_F])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_N])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_LS])
@@ -32,29 +33,33 @@ AC_DEFUN([gl_FUNC_VASNPRINTF_POSIX],
                 *yes)
                   case "$gl_cv_func_printf_directive_a" in
                     *yes)
-                      case "$gl_cv_func_printf_directive_f" in
+                      case "$gl_cv_func_printf_directive_b" in
                         *yes)
-                          case "$gl_cv_func_printf_directive_n" in
+                          case "$gl_cv_func_printf_directive_f" in
                             *yes)
-                              case "$gl_cv_func_printf_directive_ls" in
+                              case "$gl_cv_func_printf_directive_n" in
                                 *yes)
-                                  case "$gl_cv_func_printf_positions" in
+                                  case "$gl_cv_func_printf_directive_ls" in
                                     *yes)
-                                      case "$gl_cv_func_printf_flag_grouping" in
+                                      case "$gl_cv_func_printf_positions" in
                                         *yes)
-                                          case "$gl_cv_func_printf_flag_leftadjust" in
+                                          case "$gl_cv_func_printf_flag_grouping" in
                                             *yes)
-                                              case "$gl_cv_func_printf_flag_zero" in
+                                              case "$gl_cv_func_printf_flag_leftadjust" in
                                                 *yes)
-                                                  case "$gl_cv_func_printf_precision" in
+                                                  case "$gl_cv_func_printf_flag_zero" in
                                                     *yes)
-                                                      case "$gl_cv_func_printf_enomem" in
+                                                      case "$gl_cv_func_printf_precision" in
                                                         *yes)
-                                                          if test $ac_cv_func_vasnprintf = yes; then
-                                                            # vasnprintf exists and is
-                                                            # already POSIX compliant.
-                                                            gl_cv_func_vasnprintf_posix=yes
-                                                          fi
+                                                          case "$gl_cv_func_printf_enomem" in
+                                                            *yes)
+                                                              if test $ac_cv_func_vasnprintf = yes; then
+                                                                # vasnprintf exists and is
+                                                                # already POSIX compliant.
+                                                                gl_cv_func_vasnprintf_posix=yes
+                                                              fi
+                                                              ;;
+                                                          esac
                                                           ;;
                                                       esac
                                                       ;;
@@ -88,6 +93,7 @@ AC_DEFUN([gl_FUNC_VASNPRINTF_POSIX],
     gl_PREREQ_VASNPRINTF_INFINITE_DOUBLE
     gl_PREREQ_VASNPRINTF_INFINITE_LONG_DOUBLE
     gl_PREREQ_VASNPRINTF_DIRECTIVE_A
+    gl_PREREQ_VASNPRINTF_DIRECTIVE_B
     gl_PREREQ_VASNPRINTF_DIRECTIVE_F
     gl_PREREQ_VASNPRINTF_DIRECTIVE_LS
     gl_PREREQ_VASNPRINTF_FLAG_GROUPING
diff --git a/m4/vasnprintf.m4 b/m4/vasnprintf.m4
index cf451f9b03..b868aed08b 100644
--- a/m4/vasnprintf.m4
+++ b/m4/vasnprintf.m4
@@ -1,4 +1,4 @@
-# vasnprintf.m4 serial 40
+# vasnprintf.m4 serial 41
 dnl Copyright (C) 2002-2004, 2006-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -182,6 +182,21 @@ AC_DEFUN([gl_PREREQ_VASNPRINTF_DIRECTIVE_A],
   esac
 ])
 
+# Extra prerequisites of lib/vasnprintf.c for supporting the 'b' directive.
+AC_DEFUN([gl_PREREQ_VASNPRINTF_DIRECTIVE_B],
+[
+  AC_REQUIRE([gl_PRINTF_DIRECTIVE_B])
+  case "$gl_cv_func_printf_directive_b" in
+    *yes)
+      ;;
+    *)
+      AC_DEFINE([NEED_PRINTF_DIRECTIVE_B], [1],
+        [Define if the vasnprintf implementation needs special code for
+         the 'b' directive.])
+      ;;
+  esac
+])
+
 # Extra prerequisites of lib/vasnprintf.c for supporting the 'F' directive.
 AC_DEFUN([gl_PREREQ_VASNPRINTF_DIRECTIVE_F],
 [
@@ -308,6 +323,7 @@ AC_DEFUN([gl_PREREQ_VASNPRINTF_WITH_EXTRAS],
   gl_PREREQ_VASNPRINTF_INFINITE_DOUBLE
   gl_PREREQ_VASNPRINTF_INFINITE_LONG_DOUBLE
   gl_PREREQ_VASNPRINTF_DIRECTIVE_A
+  gl_PREREQ_VASNPRINTF_DIRECTIVE_B
   gl_PREREQ_VASNPRINTF_DIRECTIVE_F
   gl_PREREQ_VASNPRINTF_DIRECTIVE_LS
   gl_PREREQ_VASNPRINTF_FLAG_GROUPING
diff --git a/m4/vasnwprintf-posix.m4 b/m4/vasnwprintf-posix.m4
index 9561bcf2b6..d9dc41fa97 100644
--- a/m4/vasnwprintf-posix.m4
+++ b/m4/vasnwprintf-posix.m4
@@ -1,4 +1,4 @@
-# vasnwprintf-posix.m4 serial 1
+# vasnwprintf-posix.m4 serial 2
 dnl Copyright (C) 2007-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -11,6 +11,7 @@ AC_DEFUN([gl_FUNC_VASNWPRINTF_POSIX],
   gl_PREREQ_VASNPRINTF_INFINITE_DOUBLE
   gl_PREREQ_VASNPRINTF_INFINITE_LONG_DOUBLE
   gl_PREREQ_VASNPRINTF_DIRECTIVE_A
+  gl_PREREQ_VASNPRINTF_DIRECTIVE_B
   gl_PREREQ_VASNPRINTF_DIRECTIVE_F
   gl_PREREQ_VASNPRINTF_DIRECTIVE_LS
   gl_PREREQ_VASNPRINTF_FLAG_GROUPING
diff --git a/m4/vasprintf-posix.m4 b/m4/vasprintf-posix.m4
index 7c198a6410..1537ad52d9 100644
--- a/m4/vasprintf-posix.m4
+++ b/m4/vasprintf-posix.m4
@@ -1,4 +1,4 @@
-# vasprintf-posix.m4 serial 13
+# vasprintf-posix.m4 serial 14
 dnl Copyright (C) 2007-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -11,6 +11,7 @@ AC_DEFUN([gl_FUNC_VASPRINTF_POSIX],
   AC_REQUIRE([gl_PRINTF_INFINITE])
   AC_REQUIRE([gl_PRINTF_INFINITE_LONG_DOUBLE])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_A])
+  AC_REQUIRE([gl_PRINTF_DIRECTIVE_B])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_F])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_N])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_LS])
@@ -32,29 +33,33 @@ AC_DEFUN([gl_FUNC_VASPRINTF_POSIX],
                 *yes)
                   case "$gl_cv_func_printf_directive_a" in
                     *yes)
-                      case "$gl_cv_func_printf_directive_f" in
+                      case "$gl_cv_func_printf_directive_b" in
                         *yes)
-                          case "$gl_cv_func_printf_directive_n" in
+                          case "$gl_cv_func_printf_directive_f" in
                             *yes)
-                              case "$gl_cv_func_printf_directive_ls" in
+                              case "$gl_cv_func_printf_directive_n" in
                                 *yes)
-                                  case "$gl_cv_func_printf_positions" in
+                                  case "$gl_cv_func_printf_directive_ls" in
                                     *yes)
-                                      case "$gl_cv_func_printf_flag_grouping" in
+                                      case "$gl_cv_func_printf_positions" in
                                         *yes)
-                                          case "$gl_cv_func_printf_flag_leftadjust" in
+                                          case "$gl_cv_func_printf_flag_grouping" in
                                             *yes)
-                                              case "$gl_cv_func_printf_flag_zero" in
+                                              case "$gl_cv_func_printf_flag_leftadjust" in
                                                 *yes)
-                                                  case "$gl_cv_func_printf_precision" in
+                                                  case "$gl_cv_func_printf_flag_zero" in
                                                     *yes)
-                                                      case "$gl_cv_func_printf_enomem" in
+                                                      case "$gl_cv_func_printf_precision" in
                                                         *yes)
-                                                          if test $ac_cv_func_vasprintf = yes; then
-                                                            # vasprintf exists and is
-                                                            # already POSIX compliant.
-                                                            gl_cv_func_vasprintf_posix=yes
-                                                          fi
+                                                          case "$gl_cv_func_printf_enomem" in
+                                                            *yes)
+                                                              if test $ac_cv_func_vasprintf = yes; then
+                                                                # vasprintf exists and is
+                                                                # already POSIX compliant.
+                                                                gl_cv_func_vasprintf_posix=yes
+                                                              fi
+                                                              ;;
+                                                          esac
                                                           ;;
                                                       esac
                                                       ;;
@@ -88,6 +93,7 @@ AC_DEFUN([gl_FUNC_VASPRINTF_POSIX],
     gl_PREREQ_VASNPRINTF_INFINITE_DOUBLE
     gl_PREREQ_VASNPRINTF_INFINITE_LONG_DOUBLE
     gl_PREREQ_VASNPRINTF_DIRECTIVE_A
+    gl_PREREQ_VASNPRINTF_DIRECTIVE_B
     gl_PREREQ_VASNPRINTF_DIRECTIVE_F
     gl_PREREQ_VASNPRINTF_DIRECTIVE_LS
     gl_PREREQ_VASNPRINTF_FLAG_GROUPING
diff --git a/m4/vdprintf-posix.m4 b/m4/vdprintf-posix.m4
index 47914cd177..eb9ab8c679 100644
--- a/m4/vdprintf-posix.m4
+++ b/m4/vdprintf-posix.m4
@@ -1,4 +1,4 @@
-# vdprintf-posix.m4 serial 3
+# vdprintf-posix.m4 serial 4
 dnl Copyright (C) 2007-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -11,6 +11,7 @@ AC_DEFUN([gl_FUNC_VDPRINTF_POSIX],
   AC_REQUIRE([gl_PRINTF_INFINITE])
   AC_REQUIRE([gl_PRINTF_INFINITE_LONG_DOUBLE])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_A])
+  AC_REQUIRE([gl_PRINTF_DIRECTIVE_B])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_F])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_N])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_LS])
@@ -33,27 +34,31 @@ AC_DEFUN([gl_FUNC_VDPRINTF_POSIX],
                   *yes)
                     case "$gl_cv_func_printf_directive_a" in
                       *yes)
-                        case "$gl_cv_func_printf_directive_f" in
+                        case "$gl_cv_func_printf_directive_b" in
                           *yes)
-                            case "$gl_cv_func_printf_directive_n" in
+                            case "$gl_cv_func_printf_directive_f" in
                               *yes)
-                                case "$gl_cv_func_printf_directive_ls" in
+                                case "$gl_cv_func_printf_directive_n" in
                                   *yes)
-                                    case "$gl_cv_func_printf_positions" in
+                                    case "$gl_cv_func_printf_directive_ls" in
                                       *yes)
-                                        case "$gl_cv_func_printf_flag_grouping" in
+                                        case "$gl_cv_func_printf_positions" in
                                           *yes)
-                                            case "$gl_cv_func_printf_flag_leftadjust" in
+                                            case "$gl_cv_func_printf_flag_grouping" in
                                               *yes)
-                                                case "$gl_cv_func_printf_flag_zero" in
+                                                case "$gl_cv_func_printf_flag_leftadjust" in
                                                   *yes)
-                                                    case "$gl_cv_func_printf_precision" in
+                                                    case "$gl_cv_func_printf_flag_zero" in
                                                       *yes)
-                                                        case "$gl_cv_func_printf_enomem" in
+                                                        case "$gl_cv_func_printf_precision" in
                                                           *yes)
-                                                            # vdprintf exists and is
-                                                            # already POSIX compliant.
-                                                            gl_cv_func_vdprintf_posix=yes
+                                                            case "$gl_cv_func_printf_enomem" in
+                                                              *yes)
+                                                                # vdprintf exists and is
+                                                                # already POSIX compliant.
+                                                                gl_cv_func_vdprintf_posix=yes
+                                                                ;;
+                                                            esac
                                                             ;;
                                                         esac
                                                         ;;
@@ -88,6 +93,7 @@ AC_DEFUN([gl_FUNC_VDPRINTF_POSIX],
     gl_PREREQ_VASNPRINTF_INFINITE_DOUBLE
     gl_PREREQ_VASNPRINTF_INFINITE_LONG_DOUBLE
     gl_PREREQ_VASNPRINTF_DIRECTIVE_A
+    gl_PREREQ_VASNPRINTF_DIRECTIVE_B
     gl_PREREQ_VASNPRINTF_DIRECTIVE_F
     gl_PREREQ_VASNPRINTF_DIRECTIVE_LS
     gl_PREREQ_VASNPRINTF_FLAG_GROUPING
diff --git a/m4/vfprintf-posix.m4 b/m4/vfprintf-posix.m4
index ec68052214..17a8bad843 100644
--- a/m4/vfprintf-posix.m4
+++ b/m4/vfprintf-posix.m4
@@ -1,4 +1,4 @@
-# vfprintf-posix.m4 serial 14
+# vfprintf-posix.m4 serial 15
 dnl Copyright (C) 2007-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -11,6 +11,7 @@ AC_DEFUN([gl_FUNC_VFPRINTF_POSIX],
   AC_REQUIRE([gl_PRINTF_INFINITE])
   AC_REQUIRE([gl_PRINTF_INFINITE_LONG_DOUBLE])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_A])
+  AC_REQUIRE([gl_PRINTF_DIRECTIVE_B])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_F])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_N])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_LS])
@@ -31,27 +32,31 @@ AC_DEFUN([gl_FUNC_VFPRINTF_POSIX],
                 *yes)
                   case "$gl_cv_func_printf_directive_a" in
                     *yes)
-                      case "$gl_cv_func_printf_directive_f" in
+                      case "$gl_cv_func_printf_directive_b" in
                         *yes)
-                          case "$gl_cv_func_printf_directive_n" in
+                          case "$gl_cv_func_printf_directive_f" in
                             *yes)
-                              case "$gl_cv_func_printf_directive_ls" in
+                              case "$gl_cv_func_printf_directive_n" in
                                 *yes)
-                                  case "$gl_cv_func_printf_positions" in
+                                  case "$gl_cv_func_printf_directive_ls" in
                                     *yes)
-                                      case "$gl_cv_func_printf_flag_grouping" in
+                                      case "$gl_cv_func_printf_positions" in
                                         *yes)
-                                          case "$gl_cv_func_printf_flag_leftadjust" in
+                                          case "$gl_cv_func_printf_flag_grouping" in
                                             *yes)
-                                              case "$gl_cv_func_printf_flag_zero" in
+                                              case "$gl_cv_func_printf_flag_leftadjust" in
                                                 *yes)
-                                                  case "$gl_cv_func_printf_precision" in
+                                                  case "$gl_cv_func_printf_flag_zero" in
                                                     *yes)
-                                                      case "$gl_cv_func_printf_enomem" in
+                                                      case "$gl_cv_func_printf_precision" in
                                                         *yes)
-                                                          # vfprintf exists and is
-                                                          # already POSIX compliant.
-                                                          gl_cv_func_vfprintf_posix=yes
+                                                          case "$gl_cv_func_printf_enomem" in
+                                                            *yes)
+                                                              # vfprintf exists and is
+                                                              # already POSIX compliant.
+                                                              gl_cv_func_vfprintf_posix=yes
+                                                              ;;
+                                                          esac
                                                           ;;
                                                       esac
                                                       ;;
@@ -85,6 +90,7 @@ AC_DEFUN([gl_FUNC_VFPRINTF_POSIX],
     gl_PREREQ_VASNPRINTF_INFINITE_DOUBLE
     gl_PREREQ_VASNPRINTF_INFINITE_LONG_DOUBLE
     gl_PREREQ_VASNPRINTF_DIRECTIVE_A
+    gl_PREREQ_VASNPRINTF_DIRECTIVE_B
     gl_PREREQ_VASNPRINTF_DIRECTIVE_F
     gl_PREREQ_VASNPRINTF_DIRECTIVE_LS
     gl_PREREQ_VASNPRINTF_FLAG_GROUPING
diff --git a/m4/vsnprintf-posix.m4 b/m4/vsnprintf-posix.m4
index 5ea04a05e5..65805522d4 100644
--- a/m4/vsnprintf-posix.m4
+++ b/m4/vsnprintf-posix.m4
@@ -1,4 +1,4 @@
-# vsnprintf-posix.m4 serial 15
+# vsnprintf-posix.m4 serial 16
 dnl Copyright (C) 2007-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -11,6 +11,7 @@ AC_DEFUN([gl_FUNC_VSNPRINTF_POSIX],
   AC_REQUIRE([gl_PRINTF_INFINITE])
   AC_REQUIRE([gl_PRINTF_INFINITE_LONG_DOUBLE])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_A])
+  AC_REQUIRE([gl_PRINTF_DIRECTIVE_B])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_F])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_N])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_LS])
@@ -39,37 +40,41 @@ AC_DEFUN([gl_FUNC_VSNPRINTF_POSIX],
                   *yes)
                     case "$gl_cv_func_printf_directive_a" in
                       *yes)
-                        case "$gl_cv_func_printf_directive_f" in
+                        case "$gl_cv_func_printf_directive_b" in
                           *yes)
-                            case "$gl_cv_func_printf_directive_n" in
+                            case "$gl_cv_func_printf_directive_f" in
                               *yes)
-                                case "$gl_cv_func_printf_directive_ls" in
+                                case "$gl_cv_func_printf_directive_n" in
                                   *yes)
-                                    case "$gl_cv_func_printf_positions" in
+                                    case "$gl_cv_func_printf_directive_ls" in
                                       *yes)
-                                        case "$gl_cv_func_printf_flag_grouping" in
+                                        case "$gl_cv_func_printf_positions" in
                                           *yes)
-                                            case "$gl_cv_func_printf_flag_leftadjust" in
+                                            case "$gl_cv_func_printf_flag_grouping" in
                                               *yes)
-                                                case "$gl_cv_func_printf_flag_zero" in
+                                                case "$gl_cv_func_printf_flag_leftadjust" in
                                                   *yes)
-                                                    case "$gl_cv_func_printf_precision" in
+                                                    case "$gl_cv_func_printf_flag_zero" in
                                                       *yes)
-                                                        case "$gl_cv_func_printf_enomem" in
+                                                        case "$gl_cv_func_printf_precision" in
                                                           *yes)
-                                                            case "$gl_cv_func_snprintf_truncation_c99" in
+                                                            case "$gl_cv_func_printf_enomem" in
                                                               *yes)
-                                                                case "$gl_cv_func_snprintf_retval_c99" in
+                                                                case "$gl_cv_func_snprintf_truncation_c99" in
                                                                   *yes)
-                                                                    case "$gl_cv_func_snprintf_directive_n" in
+                                                                    case "$gl_cv_func_snprintf_retval_c99" in
                                                                       *yes)
-                                                                        case "$gl_cv_func_snprintf_size1" in
+                                                                        case "$gl_cv_func_snprintf_directive_n" in
                                                                           *yes)
-                                                                            case "$gl_cv_func_vsnprintf_zerosize_c99" in
+                                                                            case "$gl_cv_func_snprintf_size1" in
                                                                               *yes)
-                                                                                # vsnprintf exists and is
-                                                                                # already POSIX compliant.
-                                                                                gl_cv_func_vsnprintf_posix=yes
+                                                                                case "$gl_cv_func_vsnprintf_zerosize_c99" in
+                                                                                  *yes)
+                                                                                    # vsnprintf exists and is
+                                                                                    # already POSIX compliant.
+                                                                                    gl_cv_func_vsnprintf_posix=yes
+                                                                                    ;;
+                                                                                esac
                                                                                 ;;
                                                                             esac
                                                                             ;;
@@ -114,6 +119,7 @@ AC_DEFUN([gl_FUNC_VSNPRINTF_POSIX],
     gl_PREREQ_VASNPRINTF_INFINITE_DOUBLE
     gl_PREREQ_VASNPRINTF_INFINITE_LONG_DOUBLE
     gl_PREREQ_VASNPRINTF_DIRECTIVE_A
+    gl_PREREQ_VASNPRINTF_DIRECTIVE_B
     gl_PREREQ_VASNPRINTF_DIRECTIVE_F
     gl_PREREQ_VASNPRINTF_DIRECTIVE_LS
     gl_PREREQ_VASNPRINTF_FLAG_GROUPING
diff --git a/m4/vsprintf-posix.m4 b/m4/vsprintf-posix.m4
index 3ca0178ebd..716f58f761 100644
--- a/m4/vsprintf-posix.m4
+++ b/m4/vsprintf-posix.m4
@@ -1,4 +1,4 @@
-# vsprintf-posix.m4 serial 12
+# vsprintf-posix.m4 serial 13
 dnl Copyright (C) 2007-2023 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -11,6 +11,7 @@ AC_DEFUN([gl_FUNC_VSPRINTF_POSIX],
   AC_REQUIRE([gl_PRINTF_INFINITE])
   AC_REQUIRE([gl_PRINTF_INFINITE_LONG_DOUBLE])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_A])
+  AC_REQUIRE([gl_PRINTF_DIRECTIVE_B])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_F])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_N])
   AC_REQUIRE([gl_PRINTF_DIRECTIVE_LS])
@@ -31,27 +32,31 @@ AC_DEFUN([gl_FUNC_VSPRINTF_POSIX],
                 *yes)
                   case "$gl_cv_func_printf_directive_a" in
                     *yes)
-                      case "$gl_cv_func_printf_directive_f" in
+                      case "$gl_cv_func_printf_directive_b" in
                         *yes)
-                          case "$gl_cv_func_printf_directive_n" in
+                          case "$gl_cv_func_printf_directive_f" in
                             *yes)
-                              case "$gl_cv_func_printf_directive_ls" in
+                              case "$gl_cv_func_printf_directive_n" in
                                 *yes)
-                                  case "$gl_cv_func_printf_positions" in
+                                  case "$gl_cv_func_printf_directive_ls" in
                                     *yes)
-                                      case "$gl_cv_func_printf_flag_grouping" in
+                                      case "$gl_cv_func_printf_positions" in
                                         *yes)
-                                          case "$gl_cv_func_printf_flag_leftadjust" in
+                                          case "$gl_cv_func_printf_flag_grouping" in
                                             *yes)
-                                              case "$gl_cv_func_printf_flag_zero" in
+                                              case "$gl_cv_func_printf_flag_leftadjust" in
                                                 *yes)
-                                                  case "$gl_cv_func_printf_precision" in
+                                                  case "$gl_cv_func_printf_flag_zero" in
                                                     *yes)
-                                                      case "$gl_cv_func_printf_enomem" in
+                                                      case "$gl_cv_func_printf_precision" in
                                                         *yes)
-                                                          # vsprintf exists and is
-                                                          # already POSIX compliant.
-                                                          gl_cv_func_vsprintf_posix=yes
+                                                          case "$gl_cv_func_printf_enomem" in
+                                                            *yes)
+                                                              # vsprintf exists and is
+                                                              # already POSIX compliant.
+                                                              gl_cv_func_vsprintf_posix=yes
+                                                              ;;
+                                                          esac
                                                           ;;
                                                       esac
                                                       ;;
@@ -85,6 +90,7 @@ AC_DEFUN([gl_FUNC_VSPRINTF_POSIX],
     gl_PREREQ_VASNPRINTF_INFINITE_DOUBLE
     gl_PREREQ_VASNPRINTF_INFINITE_LONG_DOUBLE
     gl_PREREQ_VASNPRINTF_DIRECTIVE_A
+    gl_PREREQ_VASNPRINTF_DIRECTIVE_B
     gl_PREREQ_VASNPRINTF_DIRECTIVE_F
     gl_PREREQ_VASNPRINTF_DIRECTIVE_LS
     gl_PREREQ_VASNPRINTF_FLAG_GROUPING