libmatheval.git -

diff --git a/lib/xmath.h b/lib/xmath.h
index 921e442..4a54db1 100644
--- a/lib/xmath.h
+++ b/lib/xmath.h

@@ -48,6 +48,12 @@

#define MATH_NAN (0.0/0.0)

#endif

+#ifdef isnan

+#define MATH_ISNAN(x) isnan(x)

+#else

+#define MATH_ISNAN(x) ((x) != (x))

+#endif

+

/* Calculate cotangent of value x. */

double math_cot(double x);