@@ -474,7 +474,24 @@ enum
# include <bits/iscanonical.h>
/* Return nonzero value if X is a signaling NaN. */
-# define issignaling(x) __MATH_TG ((x), __issignaling, (x))
+# ifndef __cplusplus
+# define issignaling(x) __MATH_TG ((x), __issignaling, (x))
+# else
+ /* In C++ mode, __MATH_TG cannot be used, because it relies on
+ __builtin_types_compatible_p, which is a C-only builtin. On the
+ other hand, overloading provides the means to distinguish between
+ the floating-point types. The overloading resolution will match
+ the correct parameter (regardless of type qualifiers (i.e.: const
+ and volatile). */
+extern "C++" {
+int issignaling (float __val) { return __issignalingf (__val); }
+int issignaling (double __val) { return __issignaling (__val); }
+int issignaling (long double __val) { return __issignalingl (__val); }
+#if __HAVE_DISTINCT_FLOAT128
+int issignaling (_Float128 __val) { return __issignalingf128 (__val); }
+#endif
+} /* extern C++ */
+# endif
/* Return nonzero value if X is subnormal. */
# define issubnormal(x) (fpclassify (x) == FP_SUBNORMAL)