Re: groff/gnulib build problem: infinite(), isinf() fail using C++ on Solaris 11/sun4u with GCC 5.5.0

Fri, 19 Dec 2025 15:17:03 -0800 

Hi,

G. Branden Robinson wrote:
> Here's an abbreviated "configure && gmake V=1" build log.  I'm including
> groff's own configuration summary because that's essential information
> for me as its maintainer, and it also discloses the names of the
> compilers found and used.  I'm also including the list of header files
> gnulib decided it needed to generate.
> 
> config.status: executing depfiles commands
> 
> GNU roff version 1.23.0.4692-4b2f66
> ----------------------------------------------------------------------
>  C++ compiler and options         : g++ -std=gnu++11 -g -O2  -D_REENTRANT
>  C compiler and options           : gcc -g -O2  -D_REENTRANT
> ----------------------------------------------------------------------
> ...
> depbase=`echo src/devices/grodvi/dvi.o | sed 's|[^/]*$|.deps/&|;s|\.o$||'`;\
> g++ -std=gnu++11 -DHAVE_CONFIG_H -I. -I./src/include  -I./src/include -I./lib 
> -I./src/include -I./lib -D_REENTRANT  -g -O2 -MT src/devices/grodvi/dvi.o -MD 
> -MP -MF $depbase.Tpo -c -o src/devices/grodvi/dvi.o 
> src/devices/grodvi/dvi.cpp &&\
> mv -f $depbase.Tpo $depbase.Po
> In file included from src/devices/grodvi/dvi.cpp:26:0:
> ./lib/math.h: In function ‘bool isfinite(float)’:
> ./lib/math.h:3098:1: error: ‘bool isfinite(float)’ conflicts with a previous 
> declaration
>  _GL_MATH_CXX_REAL_FLOATING_DECL_2 (isfinite, isfinite, bool)
>  ^
> In file included from 
> /opt/csw/lib/gcc/sparc-sun-solaris2.10/5.5.0/include-fixed/math.h:23:0,
>                  from ./lib/math.h:46,
>                  from src/devices/grodvi/dvi.cpp:26:
> /usr/include/iso/math_c99.h:685:14: note: previous declaration ‘bool 
> std::isfinite(float)’
>   inline bool isfinite(float __X) { return __builtin_isfinite(__X); }
>               ^
> In file included from src/devices/grodvi/dvi.cpp:26:0:
> ./lib/math.h: In function ‘bool isfinite(double)’:
> ./lib/math.h:3098:1: error: ‘bool isfinite(double)’ conflicts with a previous 
> declaration
>  _GL_MATH_CXX_REAL_FLOATING_DECL_2 (isfinite, isfinite, bool)
>  ^
> In file included from 
> /opt/csw/lib/gcc/sparc-sun-solaris2.10/5.5.0/include-fixed/math.h:23:0,
>                  from ./lib/math.h:46,
>                  from src/devices/grodvi/dvi.cpp:26:
> /usr/include/iso/math_c99.h:710:14: note: previous declaration ‘bool 
> std::isfinite(double)’
>   inline bool isfinite(double __X) { return __builtin_isfinite(__X); }
>               ^
> In file included from src/devices/grodvi/dvi.cpp:26:0:
> ./lib/math.h: In function ‘bool isfinite(long double)’:
> ./lib/math.h:3098:1: error: ‘bool isfinite(long double)’ conflicts with a 
> previous declaration
>  _GL_MATH_CXX_REAL_FLOATING_DECL_2 (isfinite, isfinite, bool)
>  ^
> In file included from 
> /opt/csw/lib/gcc/sparc-sun-solaris2.10/5.5.0/include-fixed/math.h:23:0,
>                  from ./lib/math.h:46,
>                  from src/devices/grodvi/dvi.cpp:26:
> /usr/include/iso/math_c99.h:731:14: note: previous declaration ‘bool 
> std::isfinite(long double)’
>   inline bool isfinite(long double __X) {
>               ^
> In file included from src/devices/grodvi/dvi.cpp:26:0:
> ./lib/math.h: In function ‘bool isinf(float)’:
> ./lib/math.h:3133:1: error: ‘bool isinf(float)’ conflicts with a previous 
> declaration
>  _GL_MATH_CXX_REAL_FLOATING_DECL_2 (isinf, isinf, bool)
>  ^
> In file included from 
> /opt/csw/lib/gcc/sparc-sun-solaris2.10/5.5.0/include-fixed/math.h:23:0,
>                  from ./lib/math.h:46,
>                  from src/devices/grodvi/dvi.cpp:26:
> /usr/include/iso/math_c99.h:686:14: note: previous declaration ‘bool 
> std::isinf(float)’
>   inline bool isinf(float __X) { return __builtin_isinf(__X); }
>               ^
> In file included from src/devices/grodvi/dvi.cpp:26:0:
> ./lib/math.h: In function ‘bool isinf(double)’:
> ./lib/math.h:3133:1: error: ‘bool isinf(double)’ conflicts with a previous 
> declaration
>  _GL_MATH_CXX_REAL_FLOATING_DECL_2 (isinf, isinf, bool)
>  ^
> In file included from 
> /opt/csw/lib/gcc/sparc-sun-solaris2.10/5.5.0/include-fixed/math.h:23:0,
>                  from ./lib/math.h:46,
>                  from src/devices/grodvi/dvi.cpp:26:
> /usr/include/iso/math_c99.h:711:14: note: previous declaration ‘bool 
> std::isinf(double)’
>   inline bool isinf(double __X) { return __builtin_isinf(__X); }
>               ^
> In file included from src/devices/grodvi/dvi.cpp:26:0:
> ./lib/math.h: In function ‘bool isinf(long double)’:
> ./lib/math.h:3133:1: error: ‘bool isinf(long double)’ conflicts with a 
> previous declaration
>  _GL_MATH_CXX_REAL_FLOATING_DECL_2 (isinf, isinf, bool)
>  ^
> In file included from 
> /opt/csw/lib/gcc/sparc-sun-solaris2.10/5.5.0/include-fixed/math.h:23:0,
>                  from ./lib/math.h:46,
>                  from src/devices/grodvi/dvi.cpp:26:
> /usr/include/iso/math_c99.h:733:14: note: previous declaration ‘bool 
> std::isinf(long double)’
>   inline bool isinf(long double __X) { return __builtin_isinf(__X); }
>               ^
> gmake[2]: *** [Makefile:10882: src/devices/grodvi/dvi.o] Error 1
> gmake[2]: Leaving directory '/export/home/gbranden/groff-1.23.0.4692-4b2f66'
> gmake[1]: *** [Makefile:13270: all-recursive] Error 1
> gmake[1]: Leaving directory '/export/home/gbranden/groff-1.23.0.4692-4b2f66'
> gmake: *** [Makefile:7539: all] Error 2
> $ g++ --version
> g++ (GCC) 5.5.0
> Copyright (C) 2015 Free Software Foundation, Inc.
> This is free software; see the source for copying conditions.  There is NO
> warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
> 
> $ gcc --version
> gcc (GCC) 5.5.0
> Copyright (C) 2015 Free Software Foundation, Inc.
> This is free software; see the source for copying conditions.  There is NO
> warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
> 
> $ uname -a
> SunOS gcc-solaris11 5.11 11.3 sun4u sparc SUNW,SPARC-Enterprise

Thanks for the report.

The error occurs because
  - groff's gnulib use includes the module 'fmod',
  - the module 'fmod' depends on 'isfinite' and 'isinf'.
  - the set of overrides (isfinite, isinf, isnan, signbit) is fragile: it needs
    tweaks for various C++ compilers.

1) But 'fmod' does not need a replacement on Solaris (nor on any modern 
platform).
Therefore if you used the gnulib-tool option --conditional-dependencies, the
error should go away.

2) Another possibility is to fix this in Gnulib. Since the code is so fragile,
fixing things for this old GCC may trigger a problem on other platforms; 
therefore
that's not the way I want to go.
But note that 'fmod' being a C module, no one has actually asked for a working
isfinite() or isinf() function/macro in C++ mode. Therefore here are patches to
simply not activate a C++ declaration that no one has asked for. This should fix
things for you.

Bruno



>From 060d155810c5f016033a53c4da227263ba74d83f Mon Sep 17 00:00:00 2001
From: Bruno Haible <[email protected]>
Date: Fri, 19 Dec 2025 23:23:30 +0100
Subject: [PATCH 1/4] isfinite-no-c++: New module.

Reported by G. Branden Robinson <[email protected]> in
<https://lists.gnu.org/archive/html/bug-gnulib/2025-12/msg00150.html>.

* modules/isfinite-no-c++: New file, based on modules/isfinite.
* modules/isfinite: Essentially an alias of isfinite-no-c++ now.
* modules/isfinite-no-c++-tests: Renamed from modules/isfinite-tests.
* lib/math.in.h (isfinite): Test also GNULIB_ISFINITE_NO_CXX.
* m4/math_h.m4 (gl_MATH_H_REQUIRE_DEFAULTS): Initialize
GNULIB_ISFINITE_NO_CXX.
* modules/math-h (Makefile.am): Substitute GNULIB_ISFINITE_NO_CXX.
* modules/cbrt (Depends-on): Add isfinite-no-c++. Remove isfinite.
* modules/cbrtf (Depends-on): Likewise.
* modules/cbrtl (Depends-on): Likewise.
* modules/fma (Depends-on): Likewise.
* modules/fmaf (Depends-on): Likewise.
* modules/fmal (Depends-on): Likewise.
* modules/fmod (Depends-on): Likewise.
* modules/fmodl (Depends-on): Likewise.
* modules/hypot (Depends-on): Likewise.
* modules/hypotl (Depends-on): Likewise.
* modules/ilogb (Depends-on): Likewise.
* modules/ilogbf (Depends-on): Likewise.
* modules/ilogbl (Depends-on): Likewise.
* modules/logb (Depends-on): Likewise.
* modules/logbf (Depends-on): Likewise.
* modules/logbl (Depends-on): Likewise.
* modules/modf (Depends-on): Likewise.
* modules/modfl (Depends-on): Likewise.
* modules/remainder (Depends-on): Likewise.
* modules/remainderf (Depends-on): Likewise.
* modules/remainderl (Depends-on): Likewise.
---
 ChangeLog                                     | 34 ++++++++++++++++++
 lib/math.in.h                                 |  4 +--
 m4/math_h.m4                                  |  3 +-
 modules/cbrt                                  |  2 +-
 modules/cbrtf                                 |  2 +-
 modules/cbrtl                                 |  2 +-
 modules/fma                                   |  2 +-
 modules/fmaf                                  |  4 +--
 modules/fmal                                  |  2 +-
 modules/fmod                                  |  2 +-
 modules/fmodl                                 |  2 +-
 modules/hypot                                 |  2 +-
 modules/hypotl                                |  2 +-
 modules/ilogb                                 |  2 +-
 modules/ilogbf                                |  2 +-
 modules/ilogbl                                |  2 +-
 modules/isfinite                              | 17 +--------
 modules/isfinite-no-c++                       | 36 +++++++++++++++++++
 .../{isfinite-tests => isfinite-no-c++-tests} |  0
 modules/logb                                  |  2 +-
 modules/logbf                                 |  2 +-
 modules/logbl                                 |  2 +-
 modules/math-h                                |  1 +
 modules/modf                                  |  2 +-
 modules/modfl                                 |  2 +-
 modules/remainder                             |  2 +-
 modules/remainderf                            |  2 +-
 modules/remainderl                            |  2 +-
 28 files changed, 98 insertions(+), 41 deletions(-)
 create mode 100644 modules/isfinite-no-c++
 rename modules/{isfinite-tests => isfinite-no-c++-tests} (100%)

diff --git a/ChangeLog b/ChangeLog
index fe19efcc4b..8439755c9a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,37 @@
+2025-12-19  Bruno Haible  <[email protected]>
+
+	isfinite-no-c++: New module.
+	Reported by G. Branden Robinson <[email protected]> in
+	<https://lists.gnu.org/archive/html/bug-gnulib/2025-12/msg00150.html>.
+	* modules/isfinite-no-c++: New file, based on modules/isfinite.
+	* modules/isfinite: Essentially an alias of isfinite-no-c++ now.
+	* modules/isfinite-no-c++-tests: Renamed from modules/isfinite-tests.
+	* lib/math.in.h (isfinite): Test also GNULIB_ISFINITE_NO_CXX.
+	* m4/math_h.m4 (gl_MATH_H_REQUIRE_DEFAULTS): Initialize
+	GNULIB_ISFINITE_NO_CXX.
+	* modules/math-h (Makefile.am): Substitute GNULIB_ISFINITE_NO_CXX.
+	* modules/cbrt (Depends-on): Add isfinite-no-c++. Remove isfinite.
+	* modules/cbrtf (Depends-on): Likewise.
+	* modules/cbrtl (Depends-on): Likewise.
+	* modules/fma (Depends-on): Likewise.
+	* modules/fmaf (Depends-on): Likewise.
+	* modules/fmal (Depends-on): Likewise.
+	* modules/fmod (Depends-on): Likewise.
+	* modules/fmodl (Depends-on): Likewise.
+	* modules/hypot (Depends-on): Likewise.
+	* modules/hypotl (Depends-on): Likewise.
+	* modules/ilogb (Depends-on): Likewise.
+	* modules/ilogbf (Depends-on): Likewise.
+	* modules/ilogbl (Depends-on): Likewise.
+	* modules/logb (Depends-on): Likewise.
+	* modules/logbf (Depends-on): Likewise.
+	* modules/logbl (Depends-on): Likewise.
+	* modules/modf (Depends-on): Likewise.
+	* modules/modfl (Depends-on): Likewise.
+	* modules/remainder (Depends-on): Likewise.
+	* modules/remainderf (Depends-on): Likewise.
+	* modules/remainderl (Depends-on): Likewise.
+
 2025-12-15  Collin Funk  <[email protected]>
 
 	nanosleep: Avoid a redefinition on mingw.
diff --git a/lib/math.in.h b/lib/math.in.h
index 53450d4c60..66b23e36ef 100644
--- a/lib/math.in.h
+++ b/lib/math.in.h
@@ -2461,7 +2461,7 @@ _GL_CXXALIASWARN (yn);
    declarations.  */
 
 
-#if @GNULIB_ISFINITE@
+#if @GNULIB_ISFINITE@ || @GNULIB_ISFINITE_NO_CXX@
 # if @REPLACE_ISFINITE@
 _GL_EXTERN_C int gl_isfinitef (float x);
 _GL_EXTERN_C int gl_isfinited (double x);
@@ -2472,7 +2472,7 @@ _GL_EXTERN_C int gl_isfinitel (long double x);
     sizeof (x) == sizeof (double) ? gl_isfinited (x) : \
     gl_isfinitef (x))
 # endif
-# ifdef __cplusplus
+# if @GNULIB_ISFINITE@ && defined __cplusplus
 #  if defined isfinite || defined GNULIB_NAMESPACE
 _GL_MATH_CXX_REAL_FLOATING_DECL_1 (isfinite)
 #   undef isfinite
diff --git a/m4/math_h.m4 b/m4/math_h.m4
index 805cca471d..a8cc3c833f 100644
--- a/m4/math_h.m4
+++ b/m4/math_h.m4
@@ -1,5 +1,5 @@
 # math_h.m4
-# serial 142
+# serial 143
 dnl Copyright (C) 2007-2025 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -131,6 +131,7 @@ AC_DEFUN([gl_MATH_H_REQUIRE_DEFAULTS]
     gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ILOGBF])
     gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ILOGBL])
     gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ISFINITE])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ISFINITE_NO_CXX])
     gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ISINF])
     gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ISNAN])
     gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ISNANF])
diff --git a/modules/cbrt b/modules/cbrt
index aa6c30c53a..458f1df643 100644
--- a/modules/cbrt
+++ b/modules/cbrt
@@ -9,7 +9,7 @@ m4/mathfunc.m4
 Depends-on:
 math-h
 extensions
-isfinite        [test $HAVE_CBRT = 0]
+isfinite-no-c++ [test $HAVE_CBRT = 0]
 fabs            [test $HAVE_CBRT = 0]
 frexp           [test $HAVE_CBRT = 0]
 ldexp           [test $HAVE_CBRT = 0]
diff --git a/modules/cbrtf b/modules/cbrtf
index 0656c67999..e770857e78 100644
--- a/modules/cbrtf
+++ b/modules/cbrtf
@@ -10,7 +10,7 @@ m4/mathfunc.m4
 Depends-on:
 math-h
 extensions
-isfinite        [test $HAVE_CBRTF = 0 || test $REPLACE_CBRTF = 1]
+isfinite-no-c++ [test $HAVE_CBRTF = 0 || test $REPLACE_CBRTF = 1]
 fabsf           [test $HAVE_CBRTF = 0 || test $REPLACE_CBRTF = 1]
 frexpf          [test $HAVE_CBRTF = 0 || test $REPLACE_CBRTF = 1]
 ldexpf          [test $HAVE_CBRTF = 0 || test $REPLACE_CBRTF = 1]
diff --git a/modules/cbrtl b/modules/cbrtl
index caa6cd6efc..f8c37d5611 100644
--- a/modules/cbrtl
+++ b/modules/cbrtl
@@ -11,7 +11,7 @@ Depends-on:
 math-h
 extensions
 cbrt            [{ test $HAVE_CBRTL = 0 || test $REPLACE_CBRTL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1]
-isfinite        [{ test $HAVE_CBRTL = 0 || test $REPLACE_CBRTL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
+isfinite-no-c++ [{ test $HAVE_CBRTL = 0 || test $REPLACE_CBRTL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 frexpl          [{ test $HAVE_CBRTL = 0 || test $REPLACE_CBRTL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 ldexpl          [{ test $HAVE_CBRTL = 0 || test $REPLACE_CBRTL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 
diff --git a/modules/fma b/modules/fma
index f27d0271c1..33ebcd3a52 100644
--- a/modules/fma
+++ b/modules/fma
@@ -13,7 +13,7 @@ math-h
 float-h         [test $HAVE_FMA = 0 || test $REPLACE_FMA = 1]
 bool            [test $HAVE_FMA = 0 || test $REPLACE_FMA = 1]
 assert-h        [test $HAVE_FMA = 0 || test $REPLACE_FMA = 1]
-isfinite        [test $HAVE_FMA = 0 || test $REPLACE_FMA = 1]
+isfinite-no-c++ [test $HAVE_FMA = 0 || test $REPLACE_FMA = 1]
 integer_length  [test $HAVE_FMA = 0 || test $REPLACE_FMA = 1]
 frexp           [test $HAVE_FMA = 0 || test $REPLACE_FMA = 1]
 ldexp           [test $HAVE_FMA = 0 || test $REPLACE_FMA = 1]
diff --git a/modules/fmaf b/modules/fmaf
index 08a75385a9..f2d77b801b 100644
--- a/modules/fmaf
+++ b/modules/fmaf
@@ -14,8 +14,8 @@ math-h
 extensions
 float-h         [test $HAVE_FMAF = 0 || test $REPLACE_FMAF = 1]
 bool            [test $HAVE_FMAF = 0 || test $REPLACE_FMAF = 1]
-assert-h         [test $HAVE_FMAF = 0 || test $REPLACE_FMAF = 1]
-isfinite        [test $HAVE_FMAF = 0 || test $REPLACE_FMAF = 1]
+assert-h        [test $HAVE_FMAF = 0 || test $REPLACE_FMAF = 1]
+isfinite-no-c++ [test $HAVE_FMAF = 0 || test $REPLACE_FMAF = 1]
 integer_length  [test $HAVE_FMAF = 0 || test $REPLACE_FMAF = 1]
 frexpf          [test $HAVE_FMAF = 0 || test $REPLACE_FMAF = 1]
 ldexpf          [test $HAVE_FMAF = 0 || test $REPLACE_FMAF = 1]
diff --git a/modules/fmal b/modules/fmal
index 083cd8e068..7f9c5b8c0c 100644
--- a/modules/fmal
+++ b/modules/fmal
@@ -16,7 +16,7 @@ fma             [{ test $HAVE_FMAL = 0 || test $REPLACE_FMAL = 1; } && test $HAV
 float-h         [{ test $HAVE_FMAL = 0 || test $REPLACE_FMAL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 bool            [{ test $HAVE_FMAL = 0 || test $REPLACE_FMAL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 assert-h        [{ test $HAVE_FMAL = 0 || test $REPLACE_FMAL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
-isfinite        [{ test $HAVE_FMAL = 0 || test $REPLACE_FMAL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
+isfinite-no-c++ [{ test $HAVE_FMAL = 0 || test $REPLACE_FMAL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 integer_length  [{ test $HAVE_FMAL = 0 || test $REPLACE_FMAL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 frexpl          [{ test $HAVE_FMAL = 0 || test $REPLACE_FMAL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 ldexpl          [{ test $HAVE_FMAL = 0 || test $REPLACE_FMAL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
diff --git a/modules/fmod b/modules/fmod
index 4b0c24f32d..7d271bfb78 100644
--- a/modules/fmod
+++ b/modules/fmod
@@ -8,7 +8,7 @@ m4/mathfunc.m4
 
 Depends-on:
 math-h
-isfinite        [test $REPLACE_FMOD = 1]
+isfinite-no-c++ [test $REPLACE_FMOD = 1]
 signbit         [test $REPLACE_FMOD = 1]
 fabs            [test $REPLACE_FMOD = 1]
 frexp           [test $REPLACE_FMOD = 1]
diff --git a/modules/fmodl b/modules/fmodl
index 3e46f58d69..1a9ad6fbb2 100644
--- a/modules/fmodl
+++ b/modules/fmodl
@@ -12,7 +12,7 @@ math-h
 extensions
 fmod            [{ test $HAVE_FMODL = 0 || test $REPLACE_FMODL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1]
 float-h         [{ test $HAVE_FMODL = 0 || test $REPLACE_FMODL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
-isfinite        [{ test $HAVE_FMODL = 0 || test $REPLACE_FMODL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
+isfinite-no-c++ [{ test $HAVE_FMODL = 0 || test $REPLACE_FMODL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 signbit         [{ test $HAVE_FMODL = 0 || test $REPLACE_FMODL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 fabsl           [{ test $HAVE_FMODL = 0 || test $REPLACE_FMODL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 frexpl          [{ test $HAVE_FMODL = 0 || test $REPLACE_FMODL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
diff --git a/modules/hypot b/modules/hypot
index d12651c3c0..9e6fdc8432 100644
--- a/modules/hypot
+++ b/modules/hypot
@@ -9,7 +9,7 @@ m4/mathfunc.m4
 Depends-on:
 math-h
 extensions
-isfinite        [test $REPLACE_HYPOT = 1]
+isfinite-no-c++ [test $REPLACE_HYPOT = 1]
 fabs            [test $REPLACE_HYPOT = 1]
 frexp           [test $REPLACE_HYPOT = 1]
 ldexp           [test $REPLACE_HYPOT = 1]
diff --git a/modules/hypotl b/modules/hypotl
index b1e334b330..8668724228 100644
--- a/modules/hypotl
+++ b/modules/hypotl
@@ -10,7 +10,7 @@ Depends-on:
 math-h
 extensions
 hypot           [{ test $HAVE_HYPOTL = 0 || test $REPLACE_HYPOTL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1]
-isfinite        [{ test $HAVE_HYPOTL = 0 || test $REPLACE_HYPOTL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
+isfinite-no-c++ [{ test $HAVE_HYPOTL = 0 || test $REPLACE_HYPOTL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 fabsl           [{ test $HAVE_HYPOTL = 0 || test $REPLACE_HYPOTL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 frexpl          [{ test $HAVE_HYPOTL = 0 || test $REPLACE_HYPOTL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 ldexpl          [{ test $HAVE_HYPOTL = 0 || test $REPLACE_HYPOTL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
diff --git a/modules/ilogb b/modules/ilogb
index 04884e26b0..3afffbba2e 100644
--- a/modules/ilogb
+++ b/modules/ilogb
@@ -8,7 +8,7 @@ m4/mathfunc.m4
 
 Depends-on:
 math-h
-isfinite        [test $HAVE_ILOGB = 0 || test $REPLACE_ILOGB = 1]
+isfinite-no-c++ [test $HAVE_ILOGB = 0 || test $REPLACE_ILOGB = 1]
 frexp           [test $HAVE_ILOGB = 0 || test $REPLACE_ILOGB = 1]
 isnand          [test $HAVE_ILOGB = 0 || test $REPLACE_ILOGB = 1]
 
diff --git a/modules/ilogbf b/modules/ilogbf
index eb01143711..6fb310c864 100644
--- a/modules/ilogbf
+++ b/modules/ilogbf
@@ -10,7 +10,7 @@ m4/mathfunc.m4
 Depends-on:
 math-h
 extensions
-isfinite        [test $HAVE_ILOGBF = 0 || test $REPLACE_ILOGBF = 1]
+isfinite-no-c++ [test $HAVE_ILOGBF = 0 || test $REPLACE_ILOGBF = 1]
 frexpf          [test $HAVE_ILOGBF = 0 || test $REPLACE_ILOGBF = 1]
 isnanf          [test $HAVE_ILOGBF = 0 || test $REPLACE_ILOGBF = 1]
 
diff --git a/modules/ilogbl b/modules/ilogbl
index ef3c54b3c8..69818f9467 100644
--- a/modules/ilogbl
+++ b/modules/ilogbl
@@ -11,7 +11,7 @@ Depends-on:
 math-h
 extensions
 ilogb           [{ test $HAVE_ILOGBL = 0 || test $REPLACE_ILOGBL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1]
-isfinite        [{ test $HAVE_ILOGBL = 0 || test $REPLACE_ILOGBL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
+isfinite-no-c++ [{ test $HAVE_ILOGBL = 0 || test $REPLACE_ILOGBL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 frexpl          [{ test $HAVE_ILOGBL = 0 || test $REPLACE_ILOGBL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 isnanl          [{ test $HAVE_ILOGBL = 0 || test $REPLACE_ILOGBL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 
diff --git a/modules/isfinite b/modules/isfinite
index 68382e32a6..f62e2d6ae6 100644
--- a/modules/isfinite
+++ b/modules/isfinite
@@ -2,29 +2,14 @@ Description:
 isfinite macro: test for finite value (zero, subnormal, or normal, and not infinite or NaN).
 
 Files:
-lib/isfinite.c
-m4/isfinite.m4
-m4/check-math-lib.m4
-m4/exponentl.m4
-m4/exponentd.m4
-m4/math_h.m4
 
 Depends-on:
-math-h
-extensions
-isnanf-nolibm   [test $REPLACE_ISFINITE = 1]
-isnand-nolibm   [test $REPLACE_ISFINITE = 1]
-isnanl-nolibm   [test $REPLACE_ISFINITE = 1]
+isfinite-no-c++
 
 configure.ac:
-gl_ISFINITE
-gl_CONDITIONAL([GL_COND_OBJ_ISFINITE], [test $REPLACE_ISFINITE = 1])
 gl_MATH_MODULE_INDICATOR([isfinite])
 
 Makefile.am:
-if GL_COND_OBJ_ISFINITE
-lib_SOURCES += isfinite.c
-endif
 
 Include:
 <math.h>
diff --git a/modules/isfinite-no-c++ b/modules/isfinite-no-c++
new file mode 100644
index 0000000000..21224191ae
--- /dev/null
+++ b/modules/isfinite-no-c++
@@ -0,0 +1,36 @@
+Description:
+isfinite macro: test for finite value (zero, subnormal, or normal, and not infinite or NaN).
+
+Files:
+lib/isfinite.c
+m4/isfinite.m4
+m4/check-math-lib.m4
+m4/exponentl.m4
+m4/exponentd.m4
+m4/math_h.m4
+
+Depends-on:
+math-h
+extensions
+isnanf-nolibm   [test $REPLACE_ISFINITE = 1]
+isnand-nolibm   [test $REPLACE_ISFINITE = 1]
+isnanl-nolibm   [test $REPLACE_ISFINITE = 1]
+
+configure.ac:
+gl_ISFINITE
+gl_CONDITIONAL([GL_COND_OBJ_ISFINITE], [test $REPLACE_ISFINITE = 1])
+gl_MATH_MODULE_INDICATOR([isfinite-no-cxx])
+
+Makefile.am:
+if GL_COND_OBJ_ISFINITE
+lib_SOURCES += isfinite.c
+endif
+
+Include:
+<math.h>
+
+License:
+LGPL
+
+Maintainer:
+Ben Pfaff
diff --git a/modules/isfinite-tests b/modules/isfinite-no-c++-tests
similarity index 100%
rename from modules/isfinite-tests
rename to modules/isfinite-no-c++-tests
diff --git a/modules/logb b/modules/logb
index a7dcb2072e..ea2013ed66 100644
--- a/modules/logb
+++ b/modules/logb
@@ -9,7 +9,7 @@ m4/mathfunc.m4
 Depends-on:
 math-h
 extensions
-isfinite        [test $HAVE_LOGB = 0 || test $REPLACE_LOGB = 1]
+isfinite-no-c++ [test $HAVE_LOGB = 0 || test $REPLACE_LOGB = 1]
 frexp           [test $HAVE_LOGB = 0 || test $REPLACE_LOGB = 1]
 isnand          [test $HAVE_LOGB = 0 || test $REPLACE_LOGB = 1]
 
diff --git a/modules/logbf b/modules/logbf
index 9e633c95dd..9ea26b7ac4 100644
--- a/modules/logbf
+++ b/modules/logbf
@@ -10,7 +10,7 @@ m4/mathfunc.m4
 Depends-on:
 math-h
 extensions
-isfinite        [test $HAVE_LOGBF = 0 || test $REPLACE_LOGBF = 1]
+isfinite-no-c++ [test $HAVE_LOGBF = 0 || test $REPLACE_LOGBF = 1]
 frexpf          [test $HAVE_LOGBF = 0 || test $REPLACE_LOGBF = 1]
 isnanf          [test $HAVE_LOGBF = 0 || test $REPLACE_LOGBF = 1]
 
diff --git a/modules/logbl b/modules/logbl
index 6b06090746..6aefe42897 100644
--- a/modules/logbl
+++ b/modules/logbl
@@ -11,7 +11,7 @@ Depends-on:
 math-h
 extensions
 logb            [{ test $HAVE_LOGBL = 0 || test $REPLACE_LOGBL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1]
-isfinite        [{ test $HAVE_LOGBL = 0 || test $REPLACE_LOGBL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
+isfinite-no-c++ [{ test $HAVE_LOGBL = 0 || test $REPLACE_LOGBL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 frexpl          [{ test $HAVE_LOGBL = 0 || test $REPLACE_LOGBL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 isnanl          [{ test $HAVE_LOGBL = 0 || test $REPLACE_LOGBL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 
diff --git a/modules/math-h b/modules/math-h
index da3214ad4e..78e94cb01c 100644
--- a/modules/math-h
+++ b/modules/math-h
@@ -87,6 +87,7 @@ math.h: math.in.h $(top_builddir)/config.status $(CXXDEFS_H) $(ARG_NONNULL_H) $(
 	      -e 's/@''GNULIB_ILOGBF''@/$(GNULIB_ILOGBF)/g' \
 	      -e 's/@''GNULIB_ILOGBL''@/$(GNULIB_ILOGBL)/g' \
 	      -e 's/@''GNULIB_ISFINITE''@/$(GNULIB_ISFINITE)/g' \
+	      -e 's/@''GNULIB_ISFINITE_NO_CXX''@/$(GNULIB_ISFINITE_NO_CXX)/g' \
 	      -e 's/@''GNULIB_ISINF''@/$(GNULIB_ISINF)/g' \
 	      -e 's/@''GNULIB_ISNAN''@/$(GNULIB_ISNAN)/g' \
 	      -e 's/@''GNULIB_ISNANF''@/$(GNULIB_ISNANF)/g' \
diff --git a/modules/modf b/modules/modf
index 2df0419acb..e021c301c3 100644
--- a/modules/modf
+++ b/modules/modf
@@ -8,7 +8,7 @@ m4/mathfunc.m4
 
 Depends-on:
 math-h
-isfinite        [test $REPLACE_MODF = 1]
+isfinite-no-c++ [test $REPLACE_MODF = 1]
 trunc           [test $REPLACE_MODF = 1]
 isinf           [test $REPLACE_MODF = 1]
 
diff --git a/modules/modfl b/modules/modfl
index c05304337a..92c260e898 100644
--- a/modules/modfl
+++ b/modules/modfl
@@ -10,7 +10,7 @@ Depends-on:
 math-h
 extensions
 modf            [{ test $HAVE_MODFL = 0 || test $REPLACE_MODFL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1]
-isfinite        [{ test $HAVE_MODFL = 0 || test $REPLACE_MODFL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
+isfinite-no-c++ [{ test $HAVE_MODFL = 0 || test $REPLACE_MODFL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 truncl          [{ test $HAVE_MODFL = 0 || test $REPLACE_MODFL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 isinf           [{ test $HAVE_MODFL = 0 || test $REPLACE_MODFL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 
diff --git a/modules/remainder b/modules/remainder
index e3a1583019..ffad86a8cd 100644
--- a/modules/remainder
+++ b/modules/remainder
@@ -8,7 +8,7 @@ m4/mathfunc.m4
 
 Depends-on:
 math-h
-isfinite        [test $HAVE_REMAINDER = 0 || test $REPLACE_REMAINDER = 1]
+isfinite-no-c++ [test $HAVE_REMAINDER = 0 || test $REPLACE_REMAINDER = 1]
 signbit         [test $HAVE_REMAINDER = 0 || test $REPLACE_REMAINDER = 1]
 fabs            [test $HAVE_REMAINDER = 0 || test $REPLACE_REMAINDER = 1]
 fmod            [test $HAVE_REMAINDER = 0 || test $REPLACE_REMAINDER = 1]
diff --git a/modules/remainderf b/modules/remainderf
index e75bd1dc04..459681435f 100644
--- a/modules/remainderf
+++ b/modules/remainderf
@@ -11,7 +11,7 @@ Depends-on:
 math-h
 extensions
 remainder       [test $HAVE_REMAINDERF = 0 || test $REPLACE_REMAINDERF = 1]
-isfinite        [test $HAVE_REMAINDERF = 0 || test $REPLACE_REMAINDERF = 1]
+isfinite-no-c++ [test $HAVE_REMAINDERF = 0 || test $REPLACE_REMAINDERF = 1]
 signbit         [test $HAVE_REMAINDERF = 0 || test $REPLACE_REMAINDERF = 1]
 fabsf           [test $HAVE_REMAINDERF = 0 || test $REPLACE_REMAINDERF = 1]
 fmodf           [test $HAVE_REMAINDERF = 0 || test $REPLACE_REMAINDERF = 1]
diff --git a/modules/remainderl b/modules/remainderl
index 44bcf06533..5baebf4b27 100644
--- a/modules/remainderl
+++ b/modules/remainderl
@@ -12,7 +12,7 @@ math-h
 extensions
 remainder       [{ test $HAVE_REMAINDERL = 0 || test $REPLACE_REMAINDERL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1]
 float-h         [{ test $HAVE_REMAINDERL = 0 || test $REPLACE_REMAINDERL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
-isfinite        [{ test $HAVE_REMAINDERL = 0 || test $REPLACE_REMAINDERL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
+isfinite-no-c++ [{ test $HAVE_REMAINDERL = 0 || test $REPLACE_REMAINDERL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 signbit         [{ test $HAVE_REMAINDERL = 0 || test $REPLACE_REMAINDERL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 fabsl           [{ test $HAVE_REMAINDERL = 0 || test $REPLACE_REMAINDERL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 fmodl           [{ test $HAVE_REMAINDERL = 0 || test $REPLACE_REMAINDERL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
-- 
2.52.0


>From b368b69ba739fd3a71ca81e7bf20e4bb00b417a2 Mon Sep 17 00:00:00 2001
From: Bruno Haible <[email protected]>
Date: Fri, 19 Dec 2025 23:35:28 +0100
Subject: [PATCH 2/4] isinf-no-c++: New module.

Reported by G. Branden Robinson <[email protected]> in
<https://lists.gnu.org/archive/html/bug-gnulib/2025-12/msg00150.html>.

* modules/isinf-no-c++: New file, based on modules/isinf.
* modules/isinf: Essentially an alias of isinf-no-c++ now.
* modules/isinf-no-c++-tests: Renamed from modules/isinf-tests.
* lib/math.in.h (isinf): Test also GNULIB_ISINF_NO_CXX.
* m4/math_h.m4 (gl_MATH_H_REQUIRE_DEFAULTS): Initialize
GNULIB_ISINF_NO_CXX.
* modules/math-h (Makefile.am): Substitute GNULIB_ISINF_NO_CXX.
* modules/fmod (Depends-on): Add isinf-no-c++. Remove isinf.
* modules/fmodl (Depends-on): Likewise.
* modules/hypot (Depends-on): Likewise.
* modules/hypotl (Depends-on): Likewise.
* modules/modf (Depends-on): Likewise.
* modules/modfl (Depends-on): Likewise.
* modules/remainder (Depends-on): Likewise.
* modules/remainderf (Depends-on): Likewise.
* modules/remainderl (Depends-on): Likewise.
* modules/strtod (Depends-on): Likewise.
* modules/strtof (Depends-on): Likewise.
* modules/strtold (Depends-on): Likewise.
---
 ChangeLog                                   | 25 +++++++++++++++++
 lib/math.in.h                               |  4 +--
 m4/math_h.m4                                |  3 +-
 modules/fmod                                |  2 +-
 modules/fmodl                               |  2 +-
 modules/hypot                               |  2 +-
 modules/hypotl                              |  2 +-
 modules/isinf                               | 12 +-------
 modules/isinf-no-c++                        | 31 +++++++++++++++++++++
 modules/{isinf-tests => isinf-no-c++-tests} |  0
 modules/math-h                              |  1 +
 modules/modf                                |  2 +-
 modules/modfl                               |  2 +-
 modules/remainder                           |  2 +-
 modules/remainderf                          |  2 +-
 modules/remainderl                          |  2 +-
 modules/strtod                              |  2 +-
 modules/strtof                              |  2 +-
 modules/strtold                             |  2 +-
 19 files changed, 74 insertions(+), 26 deletions(-)
 create mode 100644 modules/isinf-no-c++
 rename modules/{isinf-tests => isinf-no-c++-tests} (100%)

diff --git a/ChangeLog b/ChangeLog
index 8439755c9a..b6dfdd68b9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,28 @@
+2025-12-19  Bruno Haible  <[email protected]>
+
+	isinf-no-c++: New module.
+	Reported by G. Branden Robinson <[email protected]> in
+	<https://lists.gnu.org/archive/html/bug-gnulib/2025-12/msg00150.html>.
+	* modules/isinf-no-c++: New file, based on modules/isinf.
+	* modules/isinf: Essentially an alias of isinf-no-c++ now.
+	* modules/isinf-no-c++-tests: Renamed from modules/isinf-tests.
+	* lib/math.in.h (isinf): Test also GNULIB_ISINF_NO_CXX.
+	* m4/math_h.m4 (gl_MATH_H_REQUIRE_DEFAULTS): Initialize
+	GNULIB_ISINF_NO_CXX.
+	* modules/math-h (Makefile.am): Substitute GNULIB_ISINF_NO_CXX.
+	* modules/fmod (Depends-on): Add isinf-no-c++. Remove isinf.
+	* modules/fmodl (Depends-on): Likewise.
+	* modules/hypot (Depends-on): Likewise.
+	* modules/hypotl (Depends-on): Likewise.
+	* modules/modf (Depends-on): Likewise.
+	* modules/modfl (Depends-on): Likewise.
+	* modules/remainder (Depends-on): Likewise.
+	* modules/remainderf (Depends-on): Likewise.
+	* modules/remainderl (Depends-on): Likewise.
+	* modules/strtod (Depends-on): Likewise.
+	* modules/strtof (Depends-on): Likewise.
+	* modules/strtold (Depends-on): Likewise.
+
 2025-12-19  Bruno Haible  <[email protected]>
 
 	isfinite-no-c++: New module.
diff --git a/lib/math.in.h b/lib/math.in.h
index 66b23e36ef..30ec254332 100644
--- a/lib/math.in.h
+++ b/lib/math.in.h
@@ -2496,7 +2496,7 @@ _GL_WARN_REAL_FLOATING_DECL (isfinite);
 #endif
 
 
-#if @GNULIB_ISINF@
+#if @GNULIB_ISINF@ || @GNULIB_ISINF_NO_CXX@
 # if @REPLACE_ISINF@
 _GL_EXTERN_C int gl_isinff (float x);
 _GL_EXTERN_C int gl_isinfd (double x);
@@ -2507,7 +2507,7 @@ _GL_EXTERN_C int gl_isinfl (long double x);
     sizeof (x) == sizeof (double) ? gl_isinfd (x) : \
     gl_isinff (x))
 # endif
-# ifdef __cplusplus
+# if @GNULIB_ISINF@ && defined __cplusplus
 #  if defined isinf || defined GNULIB_NAMESPACE
 _GL_MATH_CXX_REAL_FLOATING_DECL_1 (isinf)
 #   undef isinf
diff --git a/m4/math_h.m4 b/m4/math_h.m4
index a8cc3c833f..ad07925383 100644
--- a/m4/math_h.m4
+++ b/m4/math_h.m4
@@ -1,5 +1,5 @@
 # math_h.m4
-# serial 143
+# serial 144
 dnl Copyright (C) 2007-2025 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -133,6 +133,7 @@ AC_DEFUN([gl_MATH_H_REQUIRE_DEFAULTS]
     gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ISFINITE])
     gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ISFINITE_NO_CXX])
     gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ISINF])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ISINF_NO_CXX])
     gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ISNAN])
     gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ISNANF])
     gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ISNAND])
diff --git a/modules/fmod b/modules/fmod
index 7d271bfb78..54b0a8a350 100644
--- a/modules/fmod
+++ b/modules/fmod
@@ -15,7 +15,7 @@ frexp           [test $REPLACE_FMOD = 1]
 trunc           [test $REPLACE_FMOD = 1]
 ldexp           [test $REPLACE_FMOD = 1]
 isnand          [test $REPLACE_FMOD = 1]
-isinf           [test $REPLACE_FMOD = 1]
+isinf-no-c++    [test $REPLACE_FMOD = 1]
 
 configure.ac:
 gl_FUNC_FMOD
diff --git a/modules/fmodl b/modules/fmodl
index 1a9ad6fbb2..f4835f1e51 100644
--- a/modules/fmodl
+++ b/modules/fmodl
@@ -19,7 +19,7 @@ frexpl          [{ test $HAVE_FMODL = 0 || test $REPLACE_FMODL = 1; } && test $H
 truncl          [{ test $HAVE_FMODL = 0 || test $REPLACE_FMODL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 ldexpl          [{ test $HAVE_FMODL = 0 || test $REPLACE_FMODL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 isnanl          [{ test $HAVE_FMODL = 0 || test $REPLACE_FMODL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
-isinf           [{ test $HAVE_FMODL = 0 || test $REPLACE_FMODL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
+isinf-no-c++    [{ test $HAVE_FMODL = 0 || test $REPLACE_FMODL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 
 configure.ac:
 gl_FUNC_FMODL
diff --git a/modules/hypot b/modules/hypot
index 9e6fdc8432..001599bc24 100644
--- a/modules/hypot
+++ b/modules/hypot
@@ -14,7 +14,7 @@ fabs            [test $REPLACE_HYPOT = 1]
 frexp           [test $REPLACE_HYPOT = 1]
 ldexp           [test $REPLACE_HYPOT = 1]
 sqrt            [test $REPLACE_HYPOT = 1]
-isinf           [test $REPLACE_HYPOT = 1]
+isinf-no-c++    [test $REPLACE_HYPOT = 1]
 
 configure.ac:
 gl_FUNC_HYPOT
diff --git a/modules/hypotl b/modules/hypotl
index 8668724228..62b42e8a61 100644
--- a/modules/hypotl
+++ b/modules/hypotl
@@ -15,7 +15,7 @@ fabsl           [{ test $HAVE_HYPOTL = 0 || test $REPLACE_HYPOTL = 1; } && test
 frexpl          [{ test $HAVE_HYPOTL = 0 || test $REPLACE_HYPOTL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 ldexpl          [{ test $HAVE_HYPOTL = 0 || test $REPLACE_HYPOTL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 sqrtl           [{ test $HAVE_HYPOTL = 0 || test $REPLACE_HYPOTL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
-isinf           [{ test $HAVE_HYPOTL = 0 || test $REPLACE_HYPOTL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
+isinf-no-c++    [{ test $HAVE_HYPOTL = 0 || test $REPLACE_HYPOTL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 
 configure.ac:
 gl_FUNC_HYPOTL
diff --git a/modules/isinf b/modules/isinf
index 6a9800460f..70d7403bb4 100644
--- a/modules/isinf
+++ b/modules/isinf
@@ -2,24 +2,14 @@ Description:
 isinf macro: test for positive or negative infinity
 
 Files:
-lib/isinf.c
-m4/isinf.m4
-m4/check-math-lib.m4
 
 Depends-on:
-math-h
-extensions
-float-h         [test $REPLACE_ISINF = 1]
+isinf-no-c++
 
 configure.ac:
-gl_ISINF
-gl_CONDITIONAL([GL_COND_OBJ_ISINF], [test $REPLACE_ISINF = 1])
 gl_MATH_MODULE_INDICATOR([isinf])
 
 Makefile.am:
-if GL_COND_OBJ_ISINF
-lib_SOURCES += isinf.c
-endif
 
 Include:
 <math.h>
diff --git a/modules/isinf-no-c++ b/modules/isinf-no-c++
new file mode 100644
index 0000000000..288a0ab84b
--- /dev/null
+++ b/modules/isinf-no-c++
@@ -0,0 +1,31 @@
+Description:
+isinf macro: test for positive or negative infinity
+
+Files:
+lib/isinf.c
+m4/isinf.m4
+m4/check-math-lib.m4
+
+Depends-on:
+math-h
+extensions
+float-h         [test $REPLACE_ISINF = 1]
+
+configure.ac:
+gl_ISINF
+gl_CONDITIONAL([GL_COND_OBJ_ISINF], [test $REPLACE_ISINF = 1])
+gl_MATH_MODULE_INDICATOR([isinf-no-cxx])
+
+Makefile.am:
+if GL_COND_OBJ_ISINF
+lib_SOURCES += isinf.c
+endif
+
+Include:
+<math.h>
+
+License:
+LGPL
+
+Maintainer:
+Ben Pfaff
diff --git a/modules/isinf-tests b/modules/isinf-no-c++-tests
similarity index 100%
rename from modules/isinf-tests
rename to modules/isinf-no-c++-tests
diff --git a/modules/math-h b/modules/math-h
index 78e94cb01c..982cba2880 100644
--- a/modules/math-h
+++ b/modules/math-h
@@ -89,6 +89,7 @@ math.h: math.in.h $(top_builddir)/config.status $(CXXDEFS_H) $(ARG_NONNULL_H) $(
 	      -e 's/@''GNULIB_ISFINITE''@/$(GNULIB_ISFINITE)/g' \
 	      -e 's/@''GNULIB_ISFINITE_NO_CXX''@/$(GNULIB_ISFINITE_NO_CXX)/g' \
 	      -e 's/@''GNULIB_ISINF''@/$(GNULIB_ISINF)/g' \
+	      -e 's/@''GNULIB_ISINF_NO_CXX''@/$(GNULIB_ISINF_NO_CXX)/g' \
 	      -e 's/@''GNULIB_ISNAN''@/$(GNULIB_ISNAN)/g' \
 	      -e 's/@''GNULIB_ISNANF''@/$(GNULIB_ISNANF)/g' \
 	      -e 's/@''GNULIB_ISNAND''@/$(GNULIB_ISNAND)/g' \
diff --git a/modules/modf b/modules/modf
index e021c301c3..b4783d0dee 100644
--- a/modules/modf
+++ b/modules/modf
@@ -10,7 +10,7 @@ Depends-on:
 math-h
 isfinite-no-c++ [test $REPLACE_MODF = 1]
 trunc           [test $REPLACE_MODF = 1]
-isinf           [test $REPLACE_MODF = 1]
+isinf-no-c++    [test $REPLACE_MODF = 1]
 
 configure.ac:
 gl_FUNC_MODF
diff --git a/modules/modfl b/modules/modfl
index 92c260e898..6384737035 100644
--- a/modules/modfl
+++ b/modules/modfl
@@ -12,7 +12,7 @@ extensions
 modf            [{ test $HAVE_MODFL = 0 || test $REPLACE_MODFL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1]
 isfinite-no-c++ [{ test $HAVE_MODFL = 0 || test $REPLACE_MODFL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 truncl          [{ test $HAVE_MODFL = 0 || test $REPLACE_MODFL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
-isinf           [{ test $HAVE_MODFL = 0 || test $REPLACE_MODFL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
+isinf-no-c++    [{ test $HAVE_MODFL = 0 || test $REPLACE_MODFL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 
 configure.ac:
 gl_FUNC_MODFL
diff --git a/modules/remainder b/modules/remainder
index ffad86a8cd..8872083f26 100644
--- a/modules/remainder
+++ b/modules/remainder
@@ -13,7 +13,7 @@ signbit         [test $HAVE_REMAINDER = 0 || test $REPLACE_REMAINDER = 1]
 fabs            [test $HAVE_REMAINDER = 0 || test $REPLACE_REMAINDER = 1]
 fmod            [test $HAVE_REMAINDER = 0 || test $REPLACE_REMAINDER = 1]
 isnand          [test $HAVE_REMAINDER = 0 || test $REPLACE_REMAINDER = 1]
-isinf           [test $HAVE_REMAINDER = 0 || test $REPLACE_REMAINDER = 1]
+isinf-no-c++    [test $HAVE_REMAINDER = 0 || test $REPLACE_REMAINDER = 1]
 
 configure.ac:
 gl_FUNC_REMAINDER
diff --git a/modules/remainderf b/modules/remainderf
index 459681435f..092bbc9aa1 100644
--- a/modules/remainderf
+++ b/modules/remainderf
@@ -16,7 +16,7 @@ signbit         [test $HAVE_REMAINDERF = 0 || test $REPLACE_REMAINDERF = 1]
 fabsf           [test $HAVE_REMAINDERF = 0 || test $REPLACE_REMAINDERF = 1]
 fmodf           [test $HAVE_REMAINDERF = 0 || test $REPLACE_REMAINDERF = 1]
 isnanf          [test $HAVE_REMAINDERF = 0 || test $REPLACE_REMAINDERF = 1]
-isinf           [test $HAVE_REMAINDERF = 0 || test $REPLACE_REMAINDERF = 1]
+isinf-no-c++    [test $HAVE_REMAINDERF = 0 || test $REPLACE_REMAINDERF = 1]
 
 configure.ac:
 gl_FUNC_REMAINDERF
diff --git a/modules/remainderl b/modules/remainderl
index 5baebf4b27..d76bcc1fa9 100644
--- a/modules/remainderl
+++ b/modules/remainderl
@@ -17,7 +17,7 @@ signbit         [{ test $HAVE_REMAINDERL = 0 || test $REPLACE_REMAINDERL = 1; }
 fabsl           [{ test $HAVE_REMAINDERL = 0 || test $REPLACE_REMAINDERL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 fmodl           [{ test $HAVE_REMAINDERL = 0 || test $REPLACE_REMAINDERL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 isnanl          [{ test $HAVE_REMAINDERL = 0 || test $REPLACE_REMAINDERL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
-isinf           [{ test $HAVE_REMAINDERL = 0 || test $REPLACE_REMAINDERL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
+isinf-no-c++    [{ test $HAVE_REMAINDERL = 0 || test $REPLACE_REMAINDERL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 
 configure.ac:
 gl_FUNC_REMAINDERL
diff --git a/modules/strtod b/modules/strtod
index aaade58f7c..e1353bc0ad 100644
--- a/modules/strtod
+++ b/modules/strtod
@@ -12,7 +12,7 @@ strtod-obsolete
 c-ctype         [test $HAVE_STRTOD = 0 || test $REPLACE_STRTOD = 1]
 math-h          [test $HAVE_STRTOD = 0 || test $REPLACE_STRTOD = 1]
 bool            [test $HAVE_STRTOD = 0 || test $REPLACE_STRTOD = 1]
-isinf           [test $HAVE_STRTOD = 0 || test $REPLACE_STRTOD = 1]
+isinf-no-c++    [test $HAVE_STRTOD = 0 || test $REPLACE_STRTOD = 1]
 
 configure.ac:
 gl_FUNC_STRTOD
diff --git a/modules/strtof b/modules/strtof
index 306e77a040..4850dc30ae 100644
--- a/modules/strtof
+++ b/modules/strtof
@@ -12,7 +12,7 @@ stdlib-h
 c-ctype         [test $HAVE_STRTOF = 0 || test $REPLACE_STRTOF = 1]
 math-h          [test $HAVE_STRTOF = 0 || test $REPLACE_STRTOF = 1]
 bool            [test $HAVE_STRTOF = 0 || test $REPLACE_STRTOF = 1]
-isinf           [test $HAVE_STRTOF = 0 || test $REPLACE_STRTOF = 1]
+isinf-no-c++    [test $HAVE_STRTOF = 0 || test $REPLACE_STRTOF = 1]
 
 configure.ac:
 gl_FUNC_STRTOF
diff --git a/modules/strtold b/modules/strtold
index 9cafe3f49a..50b9ee626b 100644
--- a/modules/strtold
+++ b/modules/strtold
@@ -13,7 +13,7 @@ stdlib-h
 c-ctype         [test $HAVE_STRTOLD = 0 || test $REPLACE_STRTOLD = 1]
 math-h          [test $HAVE_STRTOLD = 0 || test $REPLACE_STRTOLD = 1]
 bool            [test $HAVE_STRTOLD = 0 || test $REPLACE_STRTOLD = 1]
-isinf           [test $HAVE_STRTOLD = 0 || test $REPLACE_STRTOLD = 1]
+isinf-no-c++    [test $HAVE_STRTOLD = 0 || test $REPLACE_STRTOLD = 1]
 strtod          [{ test $HAVE_STRTOLD = 0 || test $REPLACE_STRTOLD = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1]
 
 configure.ac:
-- 
2.52.0


>From 6f7d98fc9ae6cff837ab46c04cba3de7ce525dbf Mon Sep 17 00:00:00 2001
From: Bruno Haible <[email protected]>
Date: Fri, 19 Dec 2025 23:43:17 +0100
Subject: [PATCH 3/4] isnan-no-c++: New module.

* modules/isnan-no-c++: New file, based on modules/isnan.
* modules/isnan: Essentially an alias of isnan-no-c++ now.
* modules/isnan-no-c++-tests: Renamed from modules/isnan-tests.
* lib/math.in.h (isnan): Test also GNULIB_ISNAN_NO_CXX.
* m4/math_h.m4 (gl_MATH_H_REQUIRE_DEFAULTS): Initialize
GNULIB_ISNAN_NO_CXX.
* modules/math-h (Makefile.am): Substitute GNULIB_ISNAN_NO_CXX.
---
 ChangeLog                                   | 11 ++++++++
 lib/math.in.h                               |  4 +--
 m4/math_h.m4                                |  3 ++-
 modules/isnan                               |  9 +------
 modules/isnan-no-c++                        | 28 +++++++++++++++++++++
 modules/{isnan-tests => isnan-no-c++-tests} |  0
 modules/math-h                              |  1 +
 7 files changed, 45 insertions(+), 11 deletions(-)
 create mode 100644 modules/isnan-no-c++
 rename modules/{isnan-tests => isnan-no-c++-tests} (100%)

diff --git a/ChangeLog b/ChangeLog
index b6dfdd68b9..e45d5ece13 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2025-12-19  Bruno Haible  <[email protected]>
+
+	isnan-no-c++: New module.
+	* modules/isnan-no-c++: New file, based on modules/isnan.
+	* modules/isnan: Essentially an alias of isnan-no-c++ now.
+	* modules/isnan-no-c++-tests: Renamed from modules/isnan-tests.
+	* lib/math.in.h (isnan): Test also GNULIB_ISNAN_NO_CXX.
+	* m4/math_h.m4 (gl_MATH_H_REQUIRE_DEFAULTS): Initialize
+	GNULIB_ISNAN_NO_CXX.
+	* modules/math-h (Makefile.am): Substitute GNULIB_ISNAN_NO_CXX.
+
 2025-12-19  Bruno Haible  <[email protected]>
 
 	isinf-no-c++: New module.
diff --git a/lib/math.in.h b/lib/math.in.h
index 30ec254332..9eb0bbb642 100644
--- a/lib/math.in.h
+++ b/lib/math.in.h
@@ -2611,7 +2611,7 @@ _GL_EXTERN_C int isnanl (long double x) _GL_ATTRIBUTE_CONST;
 #endif
 
 /* This must come *after* the snippets for GNULIB_ISNANF and GNULIB_ISNANL!  */
-#if @GNULIB_ISNAN@
+#if @GNULIB_ISNAN@ || @GNULIB_ISNAN_NO_CXX@
 # if @REPLACE_ISNAN@
 /* We can't just use the isnanf macro (e.g.) as exposed by
    isnanf.h (e.g.) here, because those may end up being macros
@@ -2647,7 +2647,7 @@ _GL_EXTERN_C int rpl_isnanl (long double x) _GL_ATTRIBUTE_CONST;
     sizeof (x) == sizeof (double) ? __builtin_isnan ((double)(x)) : \
     __builtin_isnan ((float)(x)))
 # endif
-# ifdef __cplusplus
+# if @GNULIB_ISNAN@ && defined __cplusplus
 #  if defined isnan || defined GNULIB_NAMESPACE
 _GL_MATH_CXX_REAL_FLOATING_DECL_1 (isnan)
 #   undef isnan
diff --git a/m4/math_h.m4 b/m4/math_h.m4
index ad07925383..2ff9e25238 100644
--- a/m4/math_h.m4
+++ b/m4/math_h.m4
@@ -1,5 +1,5 @@
 # math_h.m4
-# serial 144
+# serial 145
 dnl Copyright (C) 2007-2025 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -135,6 +135,7 @@ AC_DEFUN([gl_MATH_H_REQUIRE_DEFAULTS]
     gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ISINF])
     gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ISINF_NO_CXX])
     gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ISNAN])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ISNAN_NO_CXX])
     gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ISNANF])
     gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ISNAND])
     gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_ISNANL])
diff --git a/modules/isnan b/modules/isnan
index ba96eb7c6f..9764e972f8 100644
--- a/modules/isnan
+++ b/modules/isnan
@@ -2,18 +2,11 @@ Description:
 isnan macro: test for NaN value.
 
 Files:
-m4/isnan.m4
 
 Depends-on:
-isnanf
-isnand
-isnanl
-math-h
-stringeq
-extensions
+isnan-no-c++
 
 configure.ac:
-gl_ISNAN
 gl_MATH_MODULE_INDICATOR([isnan])
 
 Makefile.am:
diff --git a/modules/isnan-no-c++ b/modules/isnan-no-c++
new file mode 100644
index 0000000000..db1ef396a8
--- /dev/null
+++ b/modules/isnan-no-c++
@@ -0,0 +1,28 @@
+Description:
+isnan macro: test for NaN value.
+
+Files:
+m4/isnan.m4
+
+Depends-on:
+isnanf
+isnand
+isnanl
+math-h
+stringeq
+extensions
+
+configure.ac:
+gl_ISNAN
+gl_MATH_MODULE_INDICATOR([isnan-no-cxx])
+
+Makefile.am:
+
+Include:
+<math.h>
+
+License:
+LGPL
+
+Maintainer:
+Ben Pfaff
diff --git a/modules/isnan-tests b/modules/isnan-no-c++-tests
similarity index 100%
rename from modules/isnan-tests
rename to modules/isnan-no-c++-tests
diff --git a/modules/math-h b/modules/math-h
index 982cba2880..888a9a82cc 100644
--- a/modules/math-h
+++ b/modules/math-h
@@ -91,6 +91,7 @@ math.h: math.in.h $(top_builddir)/config.status $(CXXDEFS_H) $(ARG_NONNULL_H) $(
 	      -e 's/@''GNULIB_ISINF''@/$(GNULIB_ISINF)/g' \
 	      -e 's/@''GNULIB_ISINF_NO_CXX''@/$(GNULIB_ISINF_NO_CXX)/g' \
 	      -e 's/@''GNULIB_ISNAN''@/$(GNULIB_ISNAN)/g' \
+	      -e 's/@''GNULIB_ISNAN_NO_CXX''@/$(GNULIB_ISNAN_NO_CXX)/g' \
 	      -e 's/@''GNULIB_ISNANF''@/$(GNULIB_ISNANF)/g' \
 	      -e 's/@''GNULIB_ISNAND''@/$(GNULIB_ISNAND)/g' \
 	      -e 's/@''GNULIB_ISNANL''@/$(GNULIB_ISNANL)/g' \
-- 
2.52.0


>From 7aa8d8cd87f796ed9b28439d8fb14b2503be0d0b Mon Sep 17 00:00:00 2001
From: Bruno Haible <[email protected]>
Date: Sat, 20 Dec 2025 00:02:55 +0100
Subject: [PATCH 4/4] signbit-no-c++: New module.

* modules/signbit-no-c++: New file, based on modules/signbit.
* modules/signbit: Essentially an alias of signbit-no-c++ now.
* modules/signbit-no-c++-tests: Renamed from modules/signbit-tests.
* lib/math.in.h (signbit): Test also GNULIB_SIGNBIT_NO_CXX.
* m4/math_h.m4 (gl_MATH_H_REQUIRE_DEFAULTS): Initialize
GNULIB_SIGNBIT_NO_CXX.
* modules/math-h (Makefile.am): Substitute GNULIB_SIGNBIT_NO_CXX.
* modules/copysign (Depends-on): Add signbit-no-c++. Remove signbit.
* modules/copysignf (Depends-on): Likewise.
* modules/copysignl (Depends-on): Likewise.
* modules/fabsl (Depends-on): Likewise.
* modules/fmod (Depends-on): Likewise.
* modules/fmodl (Depends-on): Likewise.
* modules/mixin/printf-posix (Depends-on): Likewise.
* modules/remainder (Depends-on): Likewise.
* modules/remainderf (Depends-on): Likewise.
* modules/remainderl (Depends-on): Likewise.
* modules/signed-nan (Depends-on): Likewise.
* modules/totalorder (Depends-on): Likewise.
* modules/totalorderf (Depends-on): Likewise.
* modules/totalorderl (Depends-on): Likewise.
* modules/totalordermag (Depends-on): Likewise.
* modules/totalordermagf (Depends-on): Likewise.
* modules/totalordermagl (Depends-on): Likewise.
* modules/c-strtod-tests (Depends-on): Likewise.
* modules/c-strtof-tests (Depends-on): Likewise.
* modules/c-strtold-tests (Depends-on): Likewise.
* modules/cbrt-ieee-tests (Depends-on): Likewise.
* modules/cbrtf-ieee-tests (Depends-on): Likewise.
* modules/cbrtl-ieee-tests (Depends-on): Likewise.
* modules/ceil-ieee-tests (Depends-on): Likewise.
* modules/ceilf-ieee-tests (Depends-on): Likewise.
* modules/ceill-ieee-tests (Depends-on): Likewise.
* modules/exp-ieee-tests (Depends-on): Likewise.
* modules/exp2-ieee-tests (Depends-on): Likewise.
* modules/exp2f-ieee-tests (Depends-on): Likewise.
* modules/exp2l-ieee-tests (Depends-on): Likewise.
* modules/expf-ieee-tests (Depends-on): Likewise.
* modules/expl-ieee-tests (Depends-on): Likewise.
* modules/expm1-ieee-tests (Depends-on): Likewise.
* modules/expm1f-ieee-tests (Depends-on): Likewise.
* modules/expm1l-ieee-tests (Depends-on): Likewise.
* modules/fabs-ieee-tests (Depends-on): Likewise.
* modules/fabs-tests (Depends-on): Likewise.
* modules/fabsf-ieee-tests (Depends-on): Likewise.
* modules/fabsf-tests (Depends-on): Likewise.
* modules/fabsl-ieee-tests (Depends-on): Likewise.
* modules/fabsl-tests (Depends-on): Likewise.
* modules/floor-ieee-tests (Depends-on): Likewise.
* modules/floorf-ieee-tests (Depends-on): Likewise.
* modules/floorl-ieee-tests (Depends-on): Likewise.
* modules/fmod-ieee-tests (Depends-on): Likewise.
* modules/fmodf-ieee-tests (Depends-on): Likewise.
* modules/fmodl-ieee-tests (Depends-on): Likewise.
* modules/frexp-ieee-tests (Depends-on): Likewise.
* modules/frexp-nolibm-tests (Depends-on): Likewise.
* modules/frexp-tests (Depends-on): Likewise.
* modules/frexpf-ieee-tests (Depends-on): Likewise.
* modules/frexpf-tests (Depends-on): Likewise.
* modules/frexpl-ieee-tests (Depends-on): Likewise.
* modules/frexpl-nolibm-tests (Depends-on): Likewise.
* modules/frexpl-tests (Depends-on): Likewise.
* modules/hypot-ieee-tests (Depends-on): Likewise.
* modules/hypotf-ieee-tests (Depends-on): Likewise.
* modules/hypotl-ieee-tests (Depends-on): Likewise.
* modules/ldexp-ieee-tests (Depends-on): Likewise.
* modules/ldexp-tests (Depends-on): Likewise.
* modules/ldexpf-ieee-tests (Depends-on): Likewise.
* modules/ldexpf-tests (Depends-on): Likewise.
* modules/ldexpl-ieee-tests (Depends-on): Likewise.
* modules/ldexpl-tests (Depends-on): Likewise.
* modules/log-ieee-tests (Depends-on): Likewise.
* modules/log10-ieee-tests (Depends-on): Likewise.
* modules/log10f-ieee-tests (Depends-on): Likewise.
* modules/log10l-ieee-tests (Depends-on): Likewise.
* modules/log1p-ieee-tests (Depends-on): Likewise.
* modules/log1pf-ieee-tests (Depends-on): Likewise.
* modules/log1pl-ieee-tests (Depends-on): Likewise.
* modules/log2-ieee-tests (Depends-on): Likewise.
* modules/log2f-ieee-tests (Depends-on): Likewise.
* modules/log2l-ieee-tests (Depends-on): Likewise.
* modules/logb-ieee-tests (Depends-on): Likewise.
* modules/logbf-ieee-tests (Depends-on): Likewise.
* modules/logbl-ieee-tests (Depends-on): Likewise.
* modules/logf-ieee-tests (Depends-on): Likewise.
* modules/logl-ieee-tests (Depends-on): Likewise.
* modules/modf-ieee-tests (Depends-on): Likewise.
* modules/modff-ieee-tests (Depends-on): Likewise.
* modules/modfl-ieee-tests (Depends-on): Likewise.
* modules/remainder-ieee-tests (Depends-on): Likewise.
* modules/remainderf-ieee-tests (Depends-on): Likewise.
* modules/remainderl-ieee-tests (Depends-on): Likewise.
* modules/rint-ieee-tests (Depends-on): Likewise.
* modules/rintf-ieee-tests (Depends-on): Likewise.
* modules/rintl-ieee-tests (Depends-on): Likewise.
* modules/round-ieee-tests (Depends-on): Likewise.
* modules/roundf-ieee-tests (Depends-on): Likewise.
* modules/roundl-ieee-tests (Depends-on): Likewise.
* modules/sqrt-ieee-tests (Depends-on): Likewise.
* modules/sqrtf-ieee-tests (Depends-on): Likewise.
* modules/sqrtl-ieee-tests (Depends-on): Likewise.
* modules/strtod-tests (Depends-on): Likewise.
* modules/strtof-tests (Depends-on): Likewise.
* modules/strtold-tests (Depends-on): Likewise.
* modules/trunc-ieee-tests (Depends-on): Likewise.
* modules/truncf-ieee-tests (Depends-on): Likewise.
* modules/truncl-ieee-tests (Depends-on): Likewise.
* modules/xstrtod-tests (Depends-on): Likewise.
* modules/xstrtold-tests (Depends-on): Likewise.
---
 ChangeLog                                     | 113 ++++++++++++++++++
 lib/math.in.h                                 |   4 +-
 m4/math_h.m4                                  |   3 +-
 modules/c-strtod-tests                        |   2 +-
 modules/c-strtof-tests                        |   2 +-
 modules/c-strtold-tests                       |   2 +-
 modules/cbrt-ieee-tests                       |   2 +-
 modules/cbrtf-ieee-tests                      |   2 +-
 modules/cbrtl-ieee-tests                      |   2 +-
 modules/ceil-ieee-tests                       |   2 +-
 modules/ceilf-ieee-tests                      |   2 +-
 modules/ceill-ieee-tests                      |   2 +-
 modules/copysign                              |   2 +-
 modules/copysignf                             |   2 +-
 modules/copysignl                             |   2 +-
 modules/exp-ieee-tests                        |   2 +-
 modules/exp2-ieee-tests                       |   2 +-
 modules/exp2f-ieee-tests                      |   2 +-
 modules/exp2l-ieee-tests                      |   2 +-
 modules/expf-ieee-tests                       |   2 +-
 modules/expl-ieee-tests                       |   2 +-
 modules/expm1-ieee-tests                      |   2 +-
 modules/expm1f-ieee-tests                     |   2 +-
 modules/expm1l-ieee-tests                     |   2 +-
 modules/fabs-ieee-tests                       |   2 +-
 modules/fabs-tests                            |   2 +-
 modules/fabsf-ieee-tests                      |   2 +-
 modules/fabsf-tests                           |   2 +-
 modules/fabsl                                 |   2 +-
 modules/fabsl-ieee-tests                      |   2 +-
 modules/fabsl-tests                           |   2 +-
 modules/floor-ieee-tests                      |   2 +-
 modules/floorf-ieee-tests                     |   2 +-
 modules/floorl-ieee-tests                     |   2 +-
 modules/fmod                                  |   2 +-
 modules/fmod-ieee-tests                       |   2 +-
 modules/fmodf-ieee-tests                      |   2 +-
 modules/fmodl                                 |   2 +-
 modules/fmodl-ieee-tests                      |   2 +-
 modules/frexp-ieee-tests                      |   2 +-
 modules/frexp-nolibm-tests                    |   2 +-
 modules/frexp-tests                           |   2 +-
 modules/frexpf-ieee-tests                     |   2 +-
 modules/frexpf-tests                          |   2 +-
 modules/frexpl-ieee-tests                     |   2 +-
 modules/frexpl-nolibm-tests                   |   2 +-
 modules/frexpl-tests                          |   2 +-
 modules/hypot-ieee-tests                      |   2 +-
 modules/hypotf-ieee-tests                     |   2 +-
 modules/hypotl-ieee-tests                     |   2 +-
 modules/ldexp-ieee-tests                      |   2 +-
 modules/ldexp-tests                           |   2 +-
 modules/ldexpf-ieee-tests                     |   2 +-
 modules/ldexpf-tests                          |   2 +-
 modules/ldexpl-ieee-tests                     |   2 +-
 modules/ldexpl-tests                          |   2 +-
 modules/log-ieee-tests                        |   2 +-
 modules/log10-ieee-tests                      |   2 +-
 modules/log10f-ieee-tests                     |   2 +-
 modules/log10l-ieee-tests                     |   2 +-
 modules/log1p-ieee-tests                      |   2 +-
 modules/log1pf-ieee-tests                     |   2 +-
 modules/log1pl-ieee-tests                     |   2 +-
 modules/log2-ieee-tests                       |   2 +-
 modules/log2f-ieee-tests                      |   2 +-
 modules/log2l-ieee-tests                      |   2 +-
 modules/logb-ieee-tests                       |   2 +-
 modules/logbf-ieee-tests                      |   2 +-
 modules/logbl-ieee-tests                      |   2 +-
 modules/logf-ieee-tests                       |   2 +-
 modules/logl-ieee-tests                       |   2 +-
 modules/math-h                                |   1 +
 modules/mixin/printf-posix                    |   2 +-
 modules/modf-ieee-tests                       |   2 +-
 modules/modff-ieee-tests                      |   2 +-
 modules/modfl-ieee-tests                      |   2 +-
 modules/remainder                             |   2 +-
 modules/remainder-ieee-tests                  |   2 +-
 modules/remainderf                            |   2 +-
 modules/remainderf-ieee-tests                 |   2 +-
 modules/remainderl                            |   2 +-
 modules/remainderl-ieee-tests                 |   2 +-
 modules/rint-ieee-tests                       |   2 +-
 modules/rintf-ieee-tests                      |   2 +-
 modules/rintl-ieee-tests                      |   2 +-
 modules/round-ieee-tests                      |   2 +-
 modules/roundf-ieee-tests                     |   2 +-
 modules/roundl-ieee-tests                     |   2 +-
 modules/signbit                               |  19 +--
 modules/signbit-no-c++                        |  38 ++++++
 .../{signbit-tests => signbit-no-c++-tests}   |   0
 modules/signed-nan                            |   2 +-
 modules/sqrt-ieee-tests                       |   2 +-
 modules/sqrtf-ieee-tests                      |   2 +-
 modules/sqrtl-ieee-tests                      |   2 +-
 modules/strtod-tests                          |   2 +-
 modules/strtof-tests                          |   2 +-
 modules/strtold-tests                         |   2 +-
 modules/totalorder                            |   2 +-
 modules/totalorderf                           |   2 +-
 modules/totalorderl                           |   2 +-
 modules/totalordermag                         |   2 +-
 modules/totalordermagf                        |   2 +-
 modules/totalordermagl                        |   2 +-
 modules/trunc-ieee-tests                      |   2 +-
 modules/truncf-ieee-tests                     |   2 +-
 modules/truncl-ieee-tests                     |   2 +-
 modules/xstrtod-tests                         |   2 +-
 modules/xstrtold-tests                        |   2 +-
 109 files changed, 259 insertions(+), 123 deletions(-)
 create mode 100644 modules/signbit-no-c++
 rename modules/{signbit-tests => signbit-no-c++-tests} (100%)

diff --git a/ChangeLog b/ChangeLog
index e45d5ece13..d3891a103f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,116 @@
+2025-12-19  Bruno Haible  <[email protected]>
+
+	signbit-no-c++: New module.
+	* modules/signbit-no-c++: New file, based on modules/signbit.
+	* modules/signbit: Essentially an alias of signbit-no-c++ now.
+	* modules/signbit-no-c++-tests: Renamed from modules/signbit-tests.
+	* lib/math.in.h (signbit): Test also GNULIB_SIGNBIT_NO_CXX.
+	* m4/math_h.m4 (gl_MATH_H_REQUIRE_DEFAULTS): Initialize
+	GNULIB_SIGNBIT_NO_CXX.
+	* modules/math-h (Makefile.am): Substitute GNULIB_SIGNBIT_NO_CXX.
+	* modules/copysign (Depends-on): Add signbit-no-c++. Remove signbit.
+	* modules/copysignf (Depends-on): Likewise.
+	* modules/copysignl (Depends-on): Likewise.
+	* modules/fabsl (Depends-on): Likewise.
+	* modules/fmod (Depends-on): Likewise.
+	* modules/fmodl (Depends-on): Likewise.
+	* modules/mixin/printf-posix (Depends-on): Likewise.
+	* modules/remainder (Depends-on): Likewise.
+	* modules/remainderf (Depends-on): Likewise.
+	* modules/remainderl (Depends-on): Likewise.
+	* modules/signed-nan (Depends-on): Likewise.
+	* modules/totalorder (Depends-on): Likewise.
+	* modules/totalorderf (Depends-on): Likewise.
+	* modules/totalorderl (Depends-on): Likewise.
+	* modules/totalordermag (Depends-on): Likewise.
+	* modules/totalordermagf (Depends-on): Likewise.
+	* modules/totalordermagl (Depends-on): Likewise.
+	* modules/c-strtod-tests (Depends-on): Likewise.
+	* modules/c-strtof-tests (Depends-on): Likewise.
+	* modules/c-strtold-tests (Depends-on): Likewise.
+	* modules/cbrt-ieee-tests (Depends-on): Likewise.
+	* modules/cbrtf-ieee-tests (Depends-on): Likewise.
+	* modules/cbrtl-ieee-tests (Depends-on): Likewise.
+	* modules/ceil-ieee-tests (Depends-on): Likewise.
+	* modules/ceilf-ieee-tests (Depends-on): Likewise.
+	* modules/ceill-ieee-tests (Depends-on): Likewise.
+	* modules/exp-ieee-tests (Depends-on): Likewise.
+	* modules/exp2-ieee-tests (Depends-on): Likewise.
+	* modules/exp2f-ieee-tests (Depends-on): Likewise.
+	* modules/exp2l-ieee-tests (Depends-on): Likewise.
+	* modules/expf-ieee-tests (Depends-on): Likewise.
+	* modules/expl-ieee-tests (Depends-on): Likewise.
+	* modules/expm1-ieee-tests (Depends-on): Likewise.
+	* modules/expm1f-ieee-tests (Depends-on): Likewise.
+	* modules/expm1l-ieee-tests (Depends-on): Likewise.
+	* modules/fabs-ieee-tests (Depends-on): Likewise.
+	* modules/fabs-tests (Depends-on): Likewise.
+	* modules/fabsf-ieee-tests (Depends-on): Likewise.
+	* modules/fabsf-tests (Depends-on): Likewise.
+	* modules/fabsl-ieee-tests (Depends-on): Likewise.
+	* modules/fabsl-tests (Depends-on): Likewise.
+	* modules/floor-ieee-tests (Depends-on): Likewise.
+	* modules/floorf-ieee-tests (Depends-on): Likewise.
+	* modules/floorl-ieee-tests (Depends-on): Likewise.
+	* modules/fmod-ieee-tests (Depends-on): Likewise.
+	* modules/fmodf-ieee-tests (Depends-on): Likewise.
+	* modules/fmodl-ieee-tests (Depends-on): Likewise.
+	* modules/frexp-ieee-tests (Depends-on): Likewise.
+	* modules/frexp-nolibm-tests (Depends-on): Likewise.
+	* modules/frexp-tests (Depends-on): Likewise.
+	* modules/frexpf-ieee-tests (Depends-on): Likewise.
+	* modules/frexpf-tests (Depends-on): Likewise.
+	* modules/frexpl-ieee-tests (Depends-on): Likewise.
+	* modules/frexpl-nolibm-tests (Depends-on): Likewise.
+	* modules/frexpl-tests (Depends-on): Likewise.
+	* modules/hypot-ieee-tests (Depends-on): Likewise.
+	* modules/hypotf-ieee-tests (Depends-on): Likewise.
+	* modules/hypotl-ieee-tests (Depends-on): Likewise.
+	* modules/ldexp-ieee-tests (Depends-on): Likewise.
+	* modules/ldexp-tests (Depends-on): Likewise.
+	* modules/ldexpf-ieee-tests (Depends-on): Likewise.
+	* modules/ldexpf-tests (Depends-on): Likewise.
+	* modules/ldexpl-ieee-tests (Depends-on): Likewise.
+	* modules/ldexpl-tests (Depends-on): Likewise.
+	* modules/log-ieee-tests (Depends-on): Likewise.
+	* modules/log10-ieee-tests (Depends-on): Likewise.
+	* modules/log10f-ieee-tests (Depends-on): Likewise.
+	* modules/log10l-ieee-tests (Depends-on): Likewise.
+	* modules/log1p-ieee-tests (Depends-on): Likewise.
+	* modules/log1pf-ieee-tests (Depends-on): Likewise.
+	* modules/log1pl-ieee-tests (Depends-on): Likewise.
+	* modules/log2-ieee-tests (Depends-on): Likewise.
+	* modules/log2f-ieee-tests (Depends-on): Likewise.
+	* modules/log2l-ieee-tests (Depends-on): Likewise.
+	* modules/logb-ieee-tests (Depends-on): Likewise.
+	* modules/logbf-ieee-tests (Depends-on): Likewise.
+	* modules/logbl-ieee-tests (Depends-on): Likewise.
+	* modules/logf-ieee-tests (Depends-on): Likewise.
+	* modules/logl-ieee-tests (Depends-on): Likewise.
+	* modules/modf-ieee-tests (Depends-on): Likewise.
+	* modules/modff-ieee-tests (Depends-on): Likewise.
+	* modules/modfl-ieee-tests (Depends-on): Likewise.
+	* modules/remainder-ieee-tests (Depends-on): Likewise.
+	* modules/remainderf-ieee-tests (Depends-on): Likewise.
+	* modules/remainderl-ieee-tests (Depends-on): Likewise.
+	* modules/rint-ieee-tests (Depends-on): Likewise.
+	* modules/rintf-ieee-tests (Depends-on): Likewise.
+	* modules/rintl-ieee-tests (Depends-on): Likewise.
+	* modules/round-ieee-tests (Depends-on): Likewise.
+	* modules/roundf-ieee-tests (Depends-on): Likewise.
+	* modules/roundl-ieee-tests (Depends-on): Likewise.
+	* modules/sqrt-ieee-tests (Depends-on): Likewise.
+	* modules/sqrtf-ieee-tests (Depends-on): Likewise.
+	* modules/sqrtl-ieee-tests (Depends-on): Likewise.
+	* modules/strtod-tests (Depends-on): Likewise.
+	* modules/strtof-tests (Depends-on): Likewise.
+	* modules/strtold-tests (Depends-on): Likewise.
+	* modules/trunc-ieee-tests (Depends-on): Likewise.
+	* modules/truncf-ieee-tests (Depends-on): Likewise.
+	* modules/truncl-ieee-tests (Depends-on): Likewise.
+	* modules/xstrtod-tests (Depends-on): Likewise.
+	* modules/xstrtold-tests (Depends-on): Likewise.
+
 2025-12-19  Bruno Haible  <[email protected]>
 
 	isnan-no-c++: New module.
diff --git a/lib/math.in.h b/lib/math.in.h
index 9eb0bbb642..650ce80a5a 100644
--- a/lib/math.in.h
+++ b/lib/math.in.h
@@ -2681,7 +2681,7 @@ _GL_WARN_REAL_FLOATING_DECL (isnan);
 #endif
 
 
-#if @GNULIB_SIGNBIT@
+#if @GNULIB_SIGNBIT@ || @GNULIB_SIGNBIT_NO_CXX@
 # if (@REPLACE_SIGNBIT_USING_BUILTINS@ \
       && (!defined __cplusplus || __cplusplus < 201103))
 #  undef signbit
@@ -2739,7 +2739,7 @@ _GL_EXTERN_C int gl_signbitl (long double arg);
     gl_signbitf (x))
 #  define GNULIB_defined_signbit 1
 # endif
-# ifdef __cplusplus
+# if @GNULIB_SIGNBIT@ && defined __cplusplus
 #  if defined signbit || defined GNULIB_NAMESPACE
 _GL_MATH_CXX_REAL_FLOATING_DECL_1 (signbit)
 #   undef signbit
diff --git a/m4/math_h.m4 b/m4/math_h.m4
index 2ff9e25238..c8a01186f0 100644
--- a/m4/math_h.m4
+++ b/m4/math_h.m4
@@ -1,5 +1,5 @@
 # math_h.m4
-# serial 145
+# serial 146
 dnl Copyright (C) 2007-2025 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -180,6 +180,7 @@ AC_DEFUN([gl_MATH_H_REQUIRE_DEFAULTS]
     gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SETPAYLOADSIGF])
     gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SETPAYLOADSIGL])
     gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SIGNBIT])
+    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SIGNBIT_NO_CXX])
     gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SINF])
     gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SINL])
     gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_SINHF])
diff --git a/modules/c-strtod-tests b/modules/c-strtod-tests
index 8a9f44321d..7dd3e9e00a 100644
--- a/modules/c-strtod-tests
+++ b/modules/c-strtod-tests
@@ -13,7 +13,7 @@ m4/codeset.m4
 Depends-on:
 float-h
 isnand-nolibm
-signbit
+signbit-no-c++
 setlocale
 thread
 nanosleep
diff --git a/modules/c-strtof-tests b/modules/c-strtof-tests
index 225d95fd64..60025cabcf 100644
--- a/modules/c-strtof-tests
+++ b/modules/c-strtof-tests
@@ -13,7 +13,7 @@ m4/codeset.m4
 Depends-on:
 float-h
 isnanf-nolibm
-signbit
+signbit-no-c++
 setlocale
 thread
 nanosleep
diff --git a/modules/c-strtold-tests b/modules/c-strtold-tests
index 823ba69c6d..c8760b00f0 100644
--- a/modules/c-strtold-tests
+++ b/modules/c-strtold-tests
@@ -13,7 +13,7 @@ m4/codeset.m4
 Depends-on:
 float-h
 isnanl-nolibm
-signbit
+signbit-no-c++
 setlocale
 thread
 nanosleep
diff --git a/modules/cbrt-ieee-tests b/modules/cbrt-ieee-tests
index 13431606ce..37d636afc9 100644
--- a/modules/cbrt-ieee-tests
+++ b/modules/cbrt-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnand-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/cbrtf-ieee-tests b/modules/cbrtf-ieee-tests
index 870b17e55b..674e591918 100644
--- a/modules/cbrtf-ieee-tests
+++ b/modules/cbrtf-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanf-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/cbrtl-ieee-tests b/modules/cbrtl-ieee-tests
index 36edb9b454..738464a132 100644
--- a/modules/cbrtl-ieee-tests
+++ b/modules/cbrtl-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanl-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/ceil-ieee-tests b/modules/ceil-ieee-tests
index 811f1f38d7..8011f8b985 100644
--- a/modules/ceil-ieee-tests
+++ b/modules/ceil-ieee-tests
@@ -8,7 +8,7 @@ Depends-on:
 isnand-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/ceilf-ieee-tests b/modules/ceilf-ieee-tests
index 86327a6750..f208d14a52 100644
--- a/modules/ceilf-ieee-tests
+++ b/modules/ceilf-ieee-tests
@@ -8,7 +8,7 @@ Depends-on:
 isnanf-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/ceill-ieee-tests b/modules/ceill-ieee-tests
index 4bd4a98000..6d9437b30e 100644
--- a/modules/ceill-ieee-tests
+++ b/modules/ceill-ieee-tests
@@ -9,7 +9,7 @@ fpucw
 isnanl-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/copysign b/modules/copysign
index 39a7842e92..97f9d1a0b4 100644
--- a/modules/copysign
+++ b/modules/copysign
@@ -8,7 +8,7 @@ m4/mathfunc.m4
 
 Depends-on:
 math-h
-signbit         [test $HAVE_COPYSIGN = 0]
+signbit-no-c++  [test $HAVE_COPYSIGN = 0]
 
 configure.ac:
 gl_FUNC_COPYSIGN
diff --git a/modules/copysignf b/modules/copysignf
index 5ef8e4af02..5725d9b4c1 100644
--- a/modules/copysignf
+++ b/modules/copysignf
@@ -9,7 +9,7 @@ m4/mathfunc.m4
 Depends-on:
 math-h
 extensions
-signbit         [test $HAVE_COPYSIGNF = 0]
+signbit-no-c++  [test $HAVE_COPYSIGNF = 0]
 
 configure.ac:
 gl_FUNC_COPYSIGNF
diff --git a/modules/copysignl b/modules/copysignl
index 55278fb6df..53e931b4b8 100644
--- a/modules/copysignl
+++ b/modules/copysignl
@@ -10,7 +10,7 @@ Depends-on:
 math-h
 extensions
 copysign        [test $HAVE_COPYSIGNL = 0 && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1]
-signbit         [test $HAVE_COPYSIGNL = 0 && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
+signbit-no-c++  [test $HAVE_COPYSIGNL = 0 && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 
 configure.ac:
 gl_FUNC_COPYSIGNL
diff --git a/modules/exp-ieee-tests b/modules/exp-ieee-tests
index b08529863d..24eb29063e 100644
--- a/modules/exp-ieee-tests
+++ b/modules/exp-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnand-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/exp2-ieee-tests b/modules/exp2-ieee-tests
index dd82010855..4bec1a6fb2 100644
--- a/modules/exp2-ieee-tests
+++ b/modules/exp2-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnand-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/exp2f-ieee-tests b/modules/exp2f-ieee-tests
index 2329697ff1..7a549eb3c4 100644
--- a/modules/exp2f-ieee-tests
+++ b/modules/exp2f-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanf-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/exp2l-ieee-tests b/modules/exp2l-ieee-tests
index f2e3ac1607..755d2cd811 100644
--- a/modules/exp2l-ieee-tests
+++ b/modules/exp2l-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanl-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/expf-ieee-tests b/modules/expf-ieee-tests
index 87d53afcb3..8f249b8ee9 100644
--- a/modules/expf-ieee-tests
+++ b/modules/expf-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanf-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/expl-ieee-tests b/modules/expl-ieee-tests
index 157853ec7a..9939062430 100644
--- a/modules/expl-ieee-tests
+++ b/modules/expl-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanl-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/expm1-ieee-tests b/modules/expm1-ieee-tests
index 1419c283d9..b24da31681 100644
--- a/modules/expm1-ieee-tests
+++ b/modules/expm1-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnand-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/expm1f-ieee-tests b/modules/expm1f-ieee-tests
index 7e0ae0e113..ca3fdc0872 100644
--- a/modules/expm1f-ieee-tests
+++ b/modules/expm1f-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanf-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/expm1l-ieee-tests b/modules/expm1l-ieee-tests
index 02c77c284b..069d8abff6 100644
--- a/modules/expm1l-ieee-tests
+++ b/modules/expm1l-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanl-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/fabs-ieee-tests b/modules/fabs-ieee-tests
index 3a97f55560..fe4d56d058 100644
--- a/modules/fabs-ieee-tests
+++ b/modules/fabs-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnand-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/fabs-tests b/modules/fabs-tests
index 3468c3494a..5b45be3bd1 100644
--- a/modules/fabs-tests
+++ b/modules/fabs-tests
@@ -7,7 +7,7 @@ tests/macros.h
 tests/randomd.c
 
 Depends-on:
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/fabsf-ieee-tests b/modules/fabsf-ieee-tests
index af4e5e564d..09431d98da 100644
--- a/modules/fabsf-ieee-tests
+++ b/modules/fabsf-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanf-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/fabsf-tests b/modules/fabsf-tests
index 6a66922c56..f3cc00e06a 100644
--- a/modules/fabsf-tests
+++ b/modules/fabsf-tests
@@ -7,7 +7,7 @@ tests/macros.h
 tests/randomf.c
 
 Depends-on:
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/fabsl b/modules/fabsl
index fbfaa96f6b..247faf9403 100644
--- a/modules/fabsl
+++ b/modules/fabsl
@@ -10,7 +10,7 @@ Depends-on:
 math-h
 extensions
 fabs            [{ test $HAVE_FABSL = 0 || test $REPLACE_FABSL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1]
-signbit         [{ test $HAVE_FABSL = 0 || test $REPLACE_FABSL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
+signbit-no-c++  [{ test $HAVE_FABSL = 0 || test $REPLACE_FABSL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 
 configure.ac:
 gl_FUNC_FABSL
diff --git a/modules/fabsl-ieee-tests b/modules/fabsl-ieee-tests
index b76b8722fa..841a4f49b2 100644
--- a/modules/fabsl-ieee-tests
+++ b/modules/fabsl-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanl-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/fabsl-tests b/modules/fabsl-tests
index 2db3a17776..2dd2de14a7 100644
--- a/modules/fabsl-tests
+++ b/modules/fabsl-tests
@@ -7,7 +7,7 @@ tests/macros.h
 tests/randoml.c
 
 Depends-on:
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/floor-ieee-tests b/modules/floor-ieee-tests
index e3eb2070e8..d6d96f5b19 100644
--- a/modules/floor-ieee-tests
+++ b/modules/floor-ieee-tests
@@ -8,7 +8,7 @@ Depends-on:
 isnand-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/floorf-ieee-tests b/modules/floorf-ieee-tests
index 97af07dee8..0bcacafcbd 100644
--- a/modules/floorf-ieee-tests
+++ b/modules/floorf-ieee-tests
@@ -8,7 +8,7 @@ Depends-on:
 isnanf-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/floorl-ieee-tests b/modules/floorl-ieee-tests
index db67a4abb0..de789a0abf 100644
--- a/modules/floorl-ieee-tests
+++ b/modules/floorl-ieee-tests
@@ -9,7 +9,7 @@ fpucw
 isnanl-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/fmod b/modules/fmod
index 54b0a8a350..12940af6a3 100644
--- a/modules/fmod
+++ b/modules/fmod
@@ -9,7 +9,7 @@ m4/mathfunc.m4
 Depends-on:
 math-h
 isfinite-no-c++ [test $REPLACE_FMOD = 1]
-signbit         [test $REPLACE_FMOD = 1]
+signbit-no-c++  [test $REPLACE_FMOD = 1]
 fabs            [test $REPLACE_FMOD = 1]
 frexp           [test $REPLACE_FMOD = 1]
 trunc           [test $REPLACE_FMOD = 1]
diff --git a/modules/fmod-ieee-tests b/modules/fmod-ieee-tests
index b7303ff0ea..fe47b78ade 100644
--- a/modules/fmod-ieee-tests
+++ b/modules/fmod-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnand-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/fmodf-ieee-tests b/modules/fmodf-ieee-tests
index 7f083eba69..6b403e4342 100644
--- a/modules/fmodf-ieee-tests
+++ b/modules/fmodf-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanf-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/fmodl b/modules/fmodl
index f4835f1e51..7c5d26724c 100644
--- a/modules/fmodl
+++ b/modules/fmodl
@@ -13,7 +13,7 @@ extensions
 fmod            [{ test $HAVE_FMODL = 0 || test $REPLACE_FMODL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1]
 float-h         [{ test $HAVE_FMODL = 0 || test $REPLACE_FMODL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 isfinite-no-c++ [{ test $HAVE_FMODL = 0 || test $REPLACE_FMODL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
-signbit         [{ test $HAVE_FMODL = 0 || test $REPLACE_FMODL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
+signbit-no-c++  [{ test $HAVE_FMODL = 0 || test $REPLACE_FMODL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 fabsl           [{ test $HAVE_FMODL = 0 || test $REPLACE_FMODL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 frexpl          [{ test $HAVE_FMODL = 0 || test $REPLACE_FMODL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 truncl          [{ test $HAVE_FMODL = 0 || test $REPLACE_FMODL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
diff --git a/modules/fmodl-ieee-tests b/modules/fmodl-ieee-tests
index 8e072a5125..2b4ea0a2bc 100644
--- a/modules/fmodl-ieee-tests
+++ b/modules/fmodl-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanl-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/frexp-ieee-tests b/modules/frexp-ieee-tests
index fd806713cc..be835d69fe 100644
--- a/modules/frexp-ieee-tests
+++ b/modules/frexp-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnand-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/frexp-nolibm-tests b/modules/frexp-nolibm-tests
index 333ff3e869..d0ad35da68 100644
--- a/modules/frexp-nolibm-tests
+++ b/modules/frexp-nolibm-tests
@@ -10,7 +10,7 @@ tests/randomd.c
 Depends-on:
 isnand-nolibm
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/frexp-tests b/modules/frexp-tests
index 7e327cbc77..0e43390a6f 100644
--- a/modules/frexp-tests
+++ b/modules/frexp-tests
@@ -10,7 +10,7 @@ tests/randomd.c
 Depends-on:
 isnand-nolibm
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/frexpf-ieee-tests b/modules/frexpf-ieee-tests
index 95d675c656..1b82902d2b 100644
--- a/modules/frexpf-ieee-tests
+++ b/modules/frexpf-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanf-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/frexpf-tests b/modules/frexpf-tests
index 7d92de13b7..00665aac4e 100644
--- a/modules/frexpf-tests
+++ b/modules/frexpf-tests
@@ -10,7 +10,7 @@ tests/randomf.c
 Depends-on:
 isnanf-nolibm
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/frexpl-ieee-tests b/modules/frexpl-ieee-tests
index 40bcb70131..e75cf52d17 100644
--- a/modules/frexpl-ieee-tests
+++ b/modules/frexpl-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanl-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/frexpl-nolibm-tests b/modules/frexpl-nolibm-tests
index a3ae1bed45..83bbdf608c 100644
--- a/modules/frexpl-nolibm-tests
+++ b/modules/frexpl-nolibm-tests
@@ -10,7 +10,7 @@ tests/randoml.c
 Depends-on:
 fpucw
 isnanl-nolibm
-signbit
+signbit-no-c++
 nan
 
 configure.ac:
diff --git a/modules/frexpl-tests b/modules/frexpl-tests
index 3e0159088a..6b1f1e8136 100644
--- a/modules/frexpl-tests
+++ b/modules/frexpl-tests
@@ -10,7 +10,7 @@ tests/randoml.c
 Depends-on:
 fpucw
 isnanl-nolibm
-signbit
+signbit-no-c++
 float-h
 nan
 
diff --git a/modules/hypot-ieee-tests b/modules/hypot-ieee-tests
index 75138308e7..c434b37b2a 100644
--- a/modules/hypot-ieee-tests
+++ b/modules/hypot-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnand-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/hypotf-ieee-tests b/modules/hypotf-ieee-tests
index a3c7d6557f..3649d3aede 100644
--- a/modules/hypotf-ieee-tests
+++ b/modules/hypotf-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanf-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/hypotl-ieee-tests b/modules/hypotl-ieee-tests
index aa58c4f299..5915fa6a8a 100644
--- a/modules/hypotl-ieee-tests
+++ b/modules/hypotl-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanl-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/ldexp-ieee-tests b/modules/ldexp-ieee-tests
index 5daaefc9d9..c36dd2ee9f 100644
--- a/modules/ldexp-ieee-tests
+++ b/modules/ldexp-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnand-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/ldexp-tests b/modules/ldexp-tests
index 4e3900d0a4..f4fa002fa4 100644
--- a/modules/ldexp-tests
+++ b/modules/ldexp-tests
@@ -9,7 +9,7 @@ tests/randomd.c
 
 Depends-on:
 isnand-nolibm
-signbit
+signbit-no-c++
 float-h
 nan
 
diff --git a/modules/ldexpf-ieee-tests b/modules/ldexpf-ieee-tests
index e65056c3d1..508f0c9dbf 100644
--- a/modules/ldexpf-ieee-tests
+++ b/modules/ldexpf-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanf-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/ldexpf-tests b/modules/ldexpf-tests
index 6dee889af0..f6938c6946 100644
--- a/modules/ldexpf-tests
+++ b/modules/ldexpf-tests
@@ -9,7 +9,7 @@ tests/randomf.c
 
 Depends-on:
 isnanf-nolibm
-signbit
+signbit-no-c++
 float-h
 nan
 
diff --git a/modules/ldexpl-ieee-tests b/modules/ldexpl-ieee-tests
index 2fbbfbbeb0..891f3736b8 100644
--- a/modules/ldexpl-ieee-tests
+++ b/modules/ldexpl-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanl-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/ldexpl-tests b/modules/ldexpl-tests
index ec04985ff0..14f02a4e7a 100644
--- a/modules/ldexpl-tests
+++ b/modules/ldexpl-tests
@@ -10,7 +10,7 @@ tests/randoml.c
 Depends-on:
 fpucw
 isnanl-nolibm
-signbit
+signbit-no-c++
 float-h
 nan
 
diff --git a/modules/log-ieee-tests b/modules/log-ieee-tests
index 5228804faa..7188233bbe 100644
--- a/modules/log-ieee-tests
+++ b/modules/log-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnand-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/log10-ieee-tests b/modules/log10-ieee-tests
index 73b93b1592..d49d0f1f8d 100644
--- a/modules/log10-ieee-tests
+++ b/modules/log10-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnand-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/log10f-ieee-tests b/modules/log10f-ieee-tests
index 6f3ef66611..8f5a2d1d42 100644
--- a/modules/log10f-ieee-tests
+++ b/modules/log10f-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanf-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/log10l-ieee-tests b/modules/log10l-ieee-tests
index 1fc171cc76..a3c3d67762 100644
--- a/modules/log10l-ieee-tests
+++ b/modules/log10l-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanl-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/log1p-ieee-tests b/modules/log1p-ieee-tests
index e8e039733f..a9ee1a1a01 100644
--- a/modules/log1p-ieee-tests
+++ b/modules/log1p-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnand-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/log1pf-ieee-tests b/modules/log1pf-ieee-tests
index bf103916d0..0bac86fa56 100644
--- a/modules/log1pf-ieee-tests
+++ b/modules/log1pf-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanf-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/log1pl-ieee-tests b/modules/log1pl-ieee-tests
index 0ac3b7c80b..182eb0ea19 100644
--- a/modules/log1pl-ieee-tests
+++ b/modules/log1pl-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanl-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/log2-ieee-tests b/modules/log2-ieee-tests
index 221b544c66..8a6a0f3365 100644
--- a/modules/log2-ieee-tests
+++ b/modules/log2-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnand-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/log2f-ieee-tests b/modules/log2f-ieee-tests
index 8cb713035c..2995afb122 100644
--- a/modules/log2f-ieee-tests
+++ b/modules/log2f-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanf-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/log2l-ieee-tests b/modules/log2l-ieee-tests
index bfdf53a34b..1ff487e1ce 100644
--- a/modules/log2l-ieee-tests
+++ b/modules/log2l-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanl-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/logb-ieee-tests b/modules/logb-ieee-tests
index 826d8e1502..58c1997997 100644
--- a/modules/logb-ieee-tests
+++ b/modules/logb-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnand-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/logbf-ieee-tests b/modules/logbf-ieee-tests
index a14017fa81..362b392f25 100644
--- a/modules/logbf-ieee-tests
+++ b/modules/logbf-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanf-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/logbl-ieee-tests b/modules/logbl-ieee-tests
index f4189abdb7..67d63a1f29 100644
--- a/modules/logbl-ieee-tests
+++ b/modules/logbl-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanl-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/logf-ieee-tests b/modules/logf-ieee-tests
index a8d7b8a953..75815da039 100644
--- a/modules/logf-ieee-tests
+++ b/modules/logf-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanf-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/logl-ieee-tests b/modules/logl-ieee-tests
index 45ba2b8b04..f088d42a76 100644
--- a/modules/logl-ieee-tests
+++ b/modules/logl-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanl-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/math-h b/modules/math-h
index 888a9a82cc..2aebc77bc9 100644
--- a/modules/math-h
+++ b/modules/math-h
@@ -136,6 +136,7 @@ math.h: math.in.h $(top_builddir)/config.status $(CXXDEFS_H) $(ARG_NONNULL_H) $(
 	      -e 's/@''GNULIB_SETPAYLOADSIGF''@/$(GNULIB_SETPAYLOADSIGF)/g' \
 	      -e 's/@''GNULIB_SETPAYLOADSIGL''@/$(GNULIB_SETPAYLOADSIGL)/g' \
 	      -e 's/@''GNULIB_SIGNBIT''@/$(GNULIB_SIGNBIT)/g' \
+	      -e 's/@''GNULIB_SIGNBIT_NO_CXX''@/$(GNULIB_SIGNBIT_NO_CXX)/g' \
 	      -e 's/@''GNULIB_SINF''@/$(GNULIB_SINF)/g' \
 	      -e 's/@''GNULIB_SINL''@/$(GNULIB_SINL)/g' \
 	      -e 's/@''GNULIB_SINHF''@/$(GNULIB_SINHF)/g' \
diff --git a/modules/mixin/printf-posix b/modules/mixin/printf-posix
index f78559142d..9eb26646e1 100644
--- a/modules/mixin/printf-posix
+++ b/modules/mixin/printf-posix
@@ -11,7 +11,7 @@ frexp-nolibm
 frexpl-nolibm
 printf-frexp
 printf-frexpl
-signbit
+signbit-no-c++
 fpucw
 
 configure.ac:
diff --git a/modules/modf-ieee-tests b/modules/modf-ieee-tests
index 645e2d9708..3da8f4509f 100644
--- a/modules/modf-ieee-tests
+++ b/modules/modf-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnand-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/modff-ieee-tests b/modules/modff-ieee-tests
index 52516fa925..bf2e2ec7b7 100644
--- a/modules/modff-ieee-tests
+++ b/modules/modff-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanf-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/modfl-ieee-tests b/modules/modfl-ieee-tests
index 1e5eb75a6e..a4f48df0de 100644
--- a/modules/modfl-ieee-tests
+++ b/modules/modfl-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanl-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/remainder b/modules/remainder
index 8872083f26..4d082d8673 100644
--- a/modules/remainder
+++ b/modules/remainder
@@ -9,7 +9,7 @@ m4/mathfunc.m4
 Depends-on:
 math-h
 isfinite-no-c++ [test $HAVE_REMAINDER = 0 || test $REPLACE_REMAINDER = 1]
-signbit         [test $HAVE_REMAINDER = 0 || test $REPLACE_REMAINDER = 1]
+signbit-no-c++  [test $HAVE_REMAINDER = 0 || test $REPLACE_REMAINDER = 1]
 fabs            [test $HAVE_REMAINDER = 0 || test $REPLACE_REMAINDER = 1]
 fmod            [test $HAVE_REMAINDER = 0 || test $REPLACE_REMAINDER = 1]
 isnand          [test $HAVE_REMAINDER = 0 || test $REPLACE_REMAINDER = 1]
diff --git a/modules/remainder-ieee-tests b/modules/remainder-ieee-tests
index 8ee2fd6571..0158b8ee53 100644
--- a/modules/remainder-ieee-tests
+++ b/modules/remainder-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnand-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/remainderf b/modules/remainderf
index 092bbc9aa1..63f3b49c2e 100644
--- a/modules/remainderf
+++ b/modules/remainderf
@@ -12,7 +12,7 @@ math-h
 extensions
 remainder       [test $HAVE_REMAINDERF = 0 || test $REPLACE_REMAINDERF = 1]
 isfinite-no-c++ [test $HAVE_REMAINDERF = 0 || test $REPLACE_REMAINDERF = 1]
-signbit         [test $HAVE_REMAINDERF = 0 || test $REPLACE_REMAINDERF = 1]
+signbit-no-c++  [test $HAVE_REMAINDERF = 0 || test $REPLACE_REMAINDERF = 1]
 fabsf           [test $HAVE_REMAINDERF = 0 || test $REPLACE_REMAINDERF = 1]
 fmodf           [test $HAVE_REMAINDERF = 0 || test $REPLACE_REMAINDERF = 1]
 isnanf          [test $HAVE_REMAINDERF = 0 || test $REPLACE_REMAINDERF = 1]
diff --git a/modules/remainderf-ieee-tests b/modules/remainderf-ieee-tests
index 97c95caabf..a6b3351580 100644
--- a/modules/remainderf-ieee-tests
+++ b/modules/remainderf-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanf-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/remainderl b/modules/remainderl
index d76bcc1fa9..2ea5fec151 100644
--- a/modules/remainderl
+++ b/modules/remainderl
@@ -13,7 +13,7 @@ extensions
 remainder       [{ test $HAVE_REMAINDERL = 0 || test $REPLACE_REMAINDERL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1]
 float-h         [{ test $HAVE_REMAINDERL = 0 || test $REPLACE_REMAINDERL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 isfinite-no-c++ [{ test $HAVE_REMAINDERL = 0 || test $REPLACE_REMAINDERL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
-signbit         [{ test $HAVE_REMAINDERL = 0 || test $REPLACE_REMAINDERL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
+signbit-no-c++  [{ test $HAVE_REMAINDERL = 0 || test $REPLACE_REMAINDERL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 fabsl           [{ test $HAVE_REMAINDERL = 0 || test $REPLACE_REMAINDERL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 fmodl           [{ test $HAVE_REMAINDERL = 0 || test $REPLACE_REMAINDERL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 isnanl          [{ test $HAVE_REMAINDERL = 0 || test $REPLACE_REMAINDERL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
diff --git a/modules/remainderl-ieee-tests b/modules/remainderl-ieee-tests
index b97940343d..70cc019867 100644
--- a/modules/remainderl-ieee-tests
+++ b/modules/remainderl-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanl-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/rint-ieee-tests b/modules/rint-ieee-tests
index eaf80d51e7..47c5a78487 100644
--- a/modules/rint-ieee-tests
+++ b/modules/rint-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnand-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/rintf-ieee-tests b/modules/rintf-ieee-tests
index a8ce07dd59..9805386df9 100644
--- a/modules/rintf-ieee-tests
+++ b/modules/rintf-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanf-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/rintl-ieee-tests b/modules/rintl-ieee-tests
index afc4ccf155..3648a5cecc 100644
--- a/modules/rintl-ieee-tests
+++ b/modules/rintl-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanl-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/round-ieee-tests b/modules/round-ieee-tests
index dc52bd3158..a024581624 100644
--- a/modules/round-ieee-tests
+++ b/modules/round-ieee-tests
@@ -8,7 +8,7 @@ Depends-on:
 isnand-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/roundf-ieee-tests b/modules/roundf-ieee-tests
index c47a8be7c7..d377a3e817 100644
--- a/modules/roundf-ieee-tests
+++ b/modules/roundf-ieee-tests
@@ -8,7 +8,7 @@ Depends-on:
 isnanf-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/roundl-ieee-tests b/modules/roundl-ieee-tests
index 114988e682..029cca3d17 100644
--- a/modules/roundl-ieee-tests
+++ b/modules/roundl-ieee-tests
@@ -8,7 +8,7 @@ Depends-on:
 isnanl-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/signbit b/modules/signbit
index 7051c141b6..9315c8bb53 100644
--- a/modules/signbit
+++ b/modules/signbit
@@ -2,31 +2,14 @@ Description:
 signbit() macro: Determine the sign bit of a floating-point number.
 
 Files:
-lib/signbitf.c
-lib/signbitd.c
-lib/signbitl.c
-lib/float+.h
-m4/signbit.m4
 
 Depends-on:
-math-h
-float-h         [test $REPLACE_SIGNBIT = 1]
-isnanf-nolibm   [test $REPLACE_SIGNBIT = 1]
-isnand-nolibm   [test $REPLACE_SIGNBIT = 1]
-isnanl-nolibm   [test $REPLACE_SIGNBIT = 1]
-fpieee          [test $REPLACE_SIGNBIT = 1]
-memcmp          [test $REPLACE_SIGNBIT = 1]
-stringeq        [test $REPLACE_SIGNBIT = 1]
+signbit-no-c++
 
 configure.ac:
-gl_SIGNBIT
-gl_CONDITIONAL([GL_COND_OBJ_SIGNBIT3], [test $REPLACE_SIGNBIT = 1])
 gl_MATH_MODULE_INDICATOR([signbit])
 
 Makefile.am:
-if GL_COND_OBJ_SIGNBIT3
-lib_SOURCES += signbitf.c signbitd.c signbitl.c
-endif
 
 Include:
 <math.h>
diff --git a/modules/signbit-no-c++ b/modules/signbit-no-c++
new file mode 100644
index 0000000000..cb612c6450
--- /dev/null
+++ b/modules/signbit-no-c++
@@ -0,0 +1,38 @@
+Description:
+signbit() macro: Determine the sign bit of a floating-point number.
+
+Files:
+lib/signbitf.c
+lib/signbitd.c
+lib/signbitl.c
+lib/float+.h
+m4/signbit.m4
+
+Depends-on:
+math-h
+float-h         [test $REPLACE_SIGNBIT = 1]
+isnanf-nolibm   [test $REPLACE_SIGNBIT = 1]
+isnand-nolibm   [test $REPLACE_SIGNBIT = 1]
+isnanl-nolibm   [test $REPLACE_SIGNBIT = 1]
+fpieee          [test $REPLACE_SIGNBIT = 1]
+memcmp          [test $REPLACE_SIGNBIT = 1]
+stringeq        [test $REPLACE_SIGNBIT = 1]
+
+configure.ac:
+gl_SIGNBIT
+gl_CONDITIONAL([GL_COND_OBJ_SIGNBIT3], [test $REPLACE_SIGNBIT = 1])
+gl_MATH_MODULE_INDICATOR([signbit-no-cxx])
+
+Makefile.am:
+if GL_COND_OBJ_SIGNBIT3
+lib_SOURCES += signbitf.c signbitd.c signbitl.c
+endif
+
+Include:
+<math.h>
+
+License:
+LGPLv2+
+
+Maintainer:
+all
diff --git a/modules/signbit-tests b/modules/signbit-no-c++-tests
similarity index 100%
rename from modules/signbit-tests
rename to modules/signbit-no-c++-tests
diff --git a/modules/signed-nan b/modules/signed-nan
index 32c6b457b7..7da33c7bc3 100644
--- a/modules/signed-nan
+++ b/modules/signed-nan
@@ -6,7 +6,7 @@ lib/signed-nan.h
 
 Depends-on:
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/sqrt-ieee-tests b/modules/sqrt-ieee-tests
index e68b5a380e..63cb3fc1b5 100644
--- a/modules/sqrt-ieee-tests
+++ b/modules/sqrt-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnand-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/sqrtf-ieee-tests b/modules/sqrtf-ieee-tests
index 40c8eee5d6..99ba570386 100644
--- a/modules/sqrtf-ieee-tests
+++ b/modules/sqrtf-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanf-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/sqrtl-ieee-tests b/modules/sqrtl-ieee-tests
index f89a7db721..bd54c181e0 100644
--- a/modules/sqrtl-ieee-tests
+++ b/modules/sqrtl-ieee-tests
@@ -9,7 +9,7 @@ Depends-on:
 isnanl-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/strtod-tests b/modules/strtod-tests
index 1aa2bb0b5a..e430d7597e 100644
--- a/modules/strtod-tests
+++ b/modules/strtod-tests
@@ -12,7 +12,7 @@ m4/codeset.m4
 Depends-on:
 float-h
 isnand-nolibm
-signbit
+signbit-no-c++
 setlocale
 
 configure.ac:
diff --git a/modules/strtof-tests b/modules/strtof-tests
index fbbff405fb..6c5c1e3ce2 100644
--- a/modules/strtof-tests
+++ b/modules/strtof-tests
@@ -12,7 +12,7 @@ m4/codeset.m4
 Depends-on:
 float-h
 isnanf-nolibm
-signbit
+signbit-no-c++
 setlocale
 
 configure.ac:
diff --git a/modules/strtold-tests b/modules/strtold-tests
index 06e75ec7ab..25bf5b7eaa 100644
--- a/modules/strtold-tests
+++ b/modules/strtold-tests
@@ -12,7 +12,7 @@ m4/codeset.m4
 Depends-on:
 float-h
 isnanl-nolibm
-signbit
+signbit-no-c++
 setlocale
 
 configure.ac:
diff --git a/modules/totalorder b/modules/totalorder
index b8f5496307..caa08826c7 100644
--- a/modules/totalorder
+++ b/modules/totalorder
@@ -11,7 +11,7 @@ Depends-on:
 math-h
 extensions
 isnand          [test $HAVE_TOTALORDER = 0 || test $REPLACE_TOTALORDER = 1]
-signbit         [test $HAVE_TOTALORDER = 0 || test $REPLACE_TOTALORDER = 1]
+signbit-no-c++  [test $HAVE_TOTALORDER = 0 || test $REPLACE_TOTALORDER = 1]
 
 configure.ac:
 gl_FUNC_TOTALORDER
diff --git a/modules/totalorderf b/modules/totalorderf
index 7918893af5..fef5830bbf 100644
--- a/modules/totalorderf
+++ b/modules/totalorderf
@@ -11,7 +11,7 @@ Depends-on:
 math-h
 extensions
 isnanf          [test $HAVE_TOTALORDERF = 0 || test $REPLACE_TOTALORDERF = 1]
-signbit         [test $HAVE_TOTALORDERF = 0 || test $REPLACE_TOTALORDERF = 1]
+signbit-no-c++  [test $HAVE_TOTALORDERF = 0 || test $REPLACE_TOTALORDERF = 1]
 
 configure.ac:
 gl_FUNC_TOTALORDERF
diff --git a/modules/totalorderl b/modules/totalorderl
index 3fe5abfc5b..7b5d6ed17a 100644
--- a/modules/totalorderl
+++ b/modules/totalorderl
@@ -15,7 +15,7 @@ totalorder      [{ test $HAVE_TOTALORDERL = 0 || test $REPLACE_TOTALORDERL = 1;
 float-h         [{ test $HAVE_TOTALORDERL = 0 || test $REPLACE_TOTALORDERL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 bool            [{ test $HAVE_TOTALORDERL = 0 || test $REPLACE_TOTALORDERL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 isnanl          [{ test $HAVE_TOTALORDERL = 0 || test $REPLACE_TOTALORDERL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
-signbit         [{ test $HAVE_TOTALORDERL = 0 || test $REPLACE_TOTALORDERL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
+signbit-no-c++  [{ test $HAVE_TOTALORDERL = 0 || test $REPLACE_TOTALORDERL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 
 configure.ac:
 gl_FUNC_TOTALORDERL
diff --git a/modules/totalordermag b/modules/totalordermag
index d051a30e25..486eaa3898 100644
--- a/modules/totalordermag
+++ b/modules/totalordermag
@@ -13,7 +13,7 @@ math-h
 extensions
 verify          [test $HAVE_TOTALORDERMAG = 0 || test $REPLACE_TOTALORDERMAG = 1]
 isnand          [test $HAVE_TOTALORDERMAG = 0 || test $REPLACE_TOTALORDERMAG = 1]
-signbit         [test $HAVE_TOTALORDERMAG = 0 || test $REPLACE_TOTALORDERMAG = 1]
+signbit-no-c++  [test $HAVE_TOTALORDERMAG = 0 || test $REPLACE_TOTALORDERMAG = 1]
 
 configure.ac:
 gl_FUNC_TOTALORDERMAG
diff --git a/modules/totalordermagf b/modules/totalordermagf
index 5c80c07b2b..959ff7406c 100644
--- a/modules/totalordermagf
+++ b/modules/totalordermagf
@@ -13,7 +13,7 @@ math-h
 extensions
 verify          [test $HAVE_TOTALORDERMAGF = 0 || test $REPLACE_TOTALORDERMAGF = 1]
 isnanf          [test $HAVE_TOTALORDERMAGF = 0 || test $REPLACE_TOTALORDERMAGF = 1]
-signbit         [test $HAVE_TOTALORDERMAGF = 0 || test $REPLACE_TOTALORDERMAGF = 1]
+signbit-no-c++  [test $HAVE_TOTALORDERMAGF = 0 || test $REPLACE_TOTALORDERMAGF = 1]
 
 configure.ac:
 gl_FUNC_TOTALORDERMAGF
diff --git a/modules/totalordermagl b/modules/totalordermagl
index 6e2707eed3..eb9548a254 100644
--- a/modules/totalordermagl
+++ b/modules/totalordermagl
@@ -17,7 +17,7 @@ bool            [{ test $HAVE_TOTALORDERMAGL = 0 || test $REPLACE_TOTALORDERMAGL
 stdint-h        [{ test $HAVE_TOTALORDERMAGL = 0 || test $REPLACE_TOTALORDERMAGL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 verify          [{ test $HAVE_TOTALORDERMAGL = 0 || test $REPLACE_TOTALORDERMAGL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 isnanl          [{ test $HAVE_TOTALORDERMAGL = 0 || test $REPLACE_TOTALORDERMAGL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
-signbit         [{ test $HAVE_TOTALORDERMAGL = 0 || test $REPLACE_TOTALORDERMAGL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
+signbit-no-c++  [{ test $HAVE_TOTALORDERMAGL = 0 || test $REPLACE_TOTALORDERMAGL = 1; } && test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 0]
 
 configure.ac:
 gl_FUNC_TOTALORDERMAGL
diff --git a/modules/trunc-ieee-tests b/modules/trunc-ieee-tests
index e03e0c5eea..08da2f63dd 100644
--- a/modules/trunc-ieee-tests
+++ b/modules/trunc-ieee-tests
@@ -8,7 +8,7 @@ Depends-on:
 isnand-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/truncf-ieee-tests b/modules/truncf-ieee-tests
index 7d8365be2a..505b3183fc 100644
--- a/modules/truncf-ieee-tests
+++ b/modules/truncf-ieee-tests
@@ -8,7 +8,7 @@ Depends-on:
 isnanf-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/truncl-ieee-tests b/modules/truncl-ieee-tests
index b8cd0b9afd..07e65238c6 100644
--- a/modules/truncl-ieee-tests
+++ b/modules/truncl-ieee-tests
@@ -9,7 +9,7 @@ fpucw
 isnanl-nolibm
 float-h
 nan
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/xstrtod-tests b/modules/xstrtod-tests
index 6cadf0015b..d6ae1b42d9 100644
--- a/modules/xstrtod-tests
+++ b/modules/xstrtod-tests
@@ -7,7 +7,7 @@ Depends-on:
 strtod
 float-h
 isnand-nolibm
-signbit
+signbit-no-c++
 
 configure.ac:
 
diff --git a/modules/xstrtold-tests b/modules/xstrtold-tests
index 263e88c680..a39d26f8e8 100644
--- a/modules/xstrtold-tests
+++ b/modules/xstrtold-tests
@@ -7,7 +7,7 @@ Depends-on:
 strtold
 float-h
 isnanl-nolibm
-signbit
+signbit-no-c++
 
 configure.ac:
 
-- 
2.52.0
  • groff/gnulib build... G. Branden Robinson
    • Re: groff/gnu... Bruno Haible via GNU roff typesetting system discussion

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