On OpenBSD 6.7, with CC=cc CXX=c++ (i.e. clang and clang++, respectively), I'm seeing these compilation errors:
depbase=`echo test-math-c++2.o | sed 's|[^/]*$|.deps/&|;s|\.o$||'`;\ c++ -DHAVE_CONFIG_H -DEXEEXT=\"\" -I. -I../../gltests -I.. -DGNULIB_STRICT_CHECKING=1 -DIN_GNULIB_TESTS=1 -I. -I../../gltests -I.. -I../../gltests/.. -I../gllib -I../../gltests/../gllib -I/home/bruno/prefix-cc/include -Wall -g -O2 -MT test-math-c++2.o -MD -MP -MF $depbase.Tpo -c -o test-math-c++2.o ../../gltests/test-math-c++2.cc &&\ mv -f $depbase.Tpo $depbase.Po In file included from ../../gltests/test-math-c++2.cc:20: /usr/include/c++/v1/cmath:314:7: error: no member named 'rpl_signbit' in the global namespace; did you mean 'gnulib::rpl_signbit'? using ::signbit; ^~ ../gllib/math.h:3085:45: note: 'gnulib::rpl_signbit' declared here _GL_MATH_CXX_REAL_FLOATING_DECL_2 (signbit, rpl_signbit, bool) ^ In file included from ../../gltests/test-math-c++2.cc:20: /usr/include/c++/v1/cmath:316:7: error: no member named 'rpl_isfinite' in the global namespace; did you mean 'gnulib::rpl_isfinite'? using ::isfinite; ^~ ../gllib/math.h:2841:46: note: 'gnulib::rpl_isfinite' declared here _GL_MATH_CXX_REAL_FLOATING_DECL_2 (isfinite, rpl_isfinite, bool) ^ In file included from ../../gltests/test-math-c++2.cc:20: /usr/include/c++/v1/cmath:317:7: error: no member named 'rpl_isinf' in the global namespace; did you mean 'gnulib::rpl_isinf'? using ::isinf; ^~ ../gllib/math.h:2875:43: note: 'gnulib::rpl_isinf' declared here _GL_MATH_CXX_REAL_FLOATING_DECL_2 (isinf, rpl_isinf, bool) ^ In file included from ../../gltests/test-math-c++2.cc:20: /usr/include/c++/v1/cmath:318:7: error: no member named 'rpl_isnan' in the global namespace; did you mean 'gnulib::rpl_isnan'? using ::isnan; ^~ ../gllib/math.h:3002:43: note: 'gnulib::rpl_isnan' declared here _GL_MATH_CXX_REAL_FLOATING_DECL_2 (isnan, rpl_isnan, bool) ^ 4 errors generated. This patch fixes it. 2020-08-19 Bruno Haible <br...@clisp.org> Fix compilation errors in C++ mode on OpenBSD. * lib/math.in.h (isfinite, isinf, isnan, signbit): In C++ mode on OpenBSD with clang, use the approach without C preprocessor macro. diff --git a/lib/math.in.h b/lib/math.in.h index 0f67127..2fa79bb 100644 --- a/lib/math.in.h +++ b/lib/math.in.h @@ -2336,7 +2336,7 @@ _GL_EXTERN_C int gl_isfinitel (long double x); # if defined isfinite || defined GNULIB_NAMESPACE _GL_MATH_CXX_REAL_FLOATING_DECL_1 (isfinite) # undef isfinite -# if __GNUC__ >= 6 || (defined __clang__ && !((defined __APPLE__ && defined __MACH__) || defined __FreeBSD__ || defined _AIX || (defined _WIN32 && !defined __CYGWIN__))) +# if __GNUC__ >= 6 || (defined __clang__ && !((defined __APPLE__ && defined __MACH__) || defined __FreeBSD__ || defined __OpenBSD__ || defined _AIX || (defined _WIN32 && !defined __CYGWIN__))) /* This platform's <cmath> possibly defines isfinite through a set of inline functions. */ _GL_MATH_CXX_REAL_FLOATING_DECL_2 (isfinite, rpl_isfinite, bool) @@ -2370,7 +2370,7 @@ _GL_EXTERN_C int gl_isinfl (long double x); # if defined isinf || defined GNULIB_NAMESPACE _GL_MATH_CXX_REAL_FLOATING_DECL_1 (isinf) # undef isinf -# if __GNUC__ >= 6 || (defined __clang__ && !((defined __APPLE__ && defined __MACH__) || defined __FreeBSD__ || (defined _WIN32 && !defined __CYGWIN__))) +# if __GNUC__ >= 6 || (defined __clang__ && !((defined __APPLE__ && defined __MACH__) || defined __FreeBSD__ || defined __OpenBSD__ || (defined _WIN32 && !defined __CYGWIN__))) /* This platform's <cmath> possibly defines isinf through a set of inline functions. */ _GL_MATH_CXX_REAL_FLOATING_DECL_2 (isinf, rpl_isinf, bool) @@ -2497,7 +2497,7 @@ _GL_EXTERN_C int rpl_isnanl (long double x) _GL_ATTRIBUTE_CONST; # if defined isnan || defined GNULIB_NAMESPACE _GL_MATH_CXX_REAL_FLOATING_DECL_1 (isnan) # undef isnan -# if __GNUC__ >= 6 || (defined __clang__ && !((defined __APPLE__ && defined __MACH__) || defined __FreeBSD__ || (defined _WIN32 && !defined __CYGWIN__))) +# if __GNUC__ >= 6 || (defined __clang__ && !((defined __APPLE__ && defined __MACH__) || defined __FreeBSD__ || defined __OpenBSD__ || (defined _WIN32 && !defined __CYGWIN__))) /* This platform's <cmath> possibly defines isnan through a set of inline functions. */ _GL_MATH_CXX_REAL_FLOATING_DECL_2 (isnan, rpl_isnan, bool) @@ -2580,7 +2580,7 @@ _GL_EXTERN_C int gl_signbitl (long double arg); # if defined signbit || defined GNULIB_NAMESPACE _GL_MATH_CXX_REAL_FLOATING_DECL_1 (signbit) # undef signbit -# if __GNUC__ >= 6 || (defined __clang__ && !((defined __APPLE__ && defined __MACH__) || defined __FreeBSD__ || defined _AIX || (defined _WIN32 && !defined __CYGWIN__))) +# if __GNUC__ >= 6 || (defined __clang__ && !((defined __APPLE__ && defined __MACH__) || defined __FreeBSD__ || defined __OpenBSD__ || defined _AIX || (defined _WIN32 && !defined __CYGWIN__))) /* This platform's <cmath> possibly defines signbit through a set of inline functions. */ _GL_MATH_CXX_REAL_FLOATING_DECL_2 (signbit, rpl_signbit, bool)