diff --git a/include/c99_math.h b/include/c99_math.h
index 250e08d44cf..e906c26aa54 100644
--- a/include/c99_math.h
+++ b/include/c99_math.h
@@ -185,4 +185,27 @@ fpclassify(double x)
 #endif
 
 
+/* Since C++11, the following functions are part of the std namespace. Their C
+ * counteparts should still exist in the global namespace, however cmath
+ * undefines those functions, which in glibc 2.23, are defined as macros rather
+ * than functions as in glibc 2.22.
+ */
+#if __cplusplus >= 201103L && (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 23))
+#include <cmath>
+
+using std::fpclassify;
+using std::isfinite;
+using std::isinf;
+using std::isnan;
+using std::isnormal;
+using std::signbit;
+using std::isgreater;
+using std::isgreaterequal;
+using std::isless;
+using std::islessequal;
+using std::islessgreater;
+using std::isunordered;
+#endif
+
+
 #endif /* #define _C99_MATH_H_ */