libmatheval.git -

diff --git a/lib/xmath.c b/lib/xmath.c
index 1310b2f..1bd5f81 100644
--- a/lib/xmath.c
+++ b/lib/xmath.c

@@ -162,7 +162,7 @@ math_step(double x)

/*

* Calculate step function value.

*/

- return (x < 0) ? 0 : 1;

+ return MATH_ISNAN(x) ? x : ((x < 0) ? 0 : 1);

}

double

@@ -171,7 +171,7 @@ math_delta(double x)

/*

* Calculate delta function value.

*/

- return (x == 0) ? MATH_INFINITY : 0;

+ return MATH_ISNAN(x) ? x : ((x == 0) ? MATH_INFINITY : 0);

}

double

@@ -180,5 +180,5 @@ math_nandelta(double x)

/*

* Calculate modified delta function value.

*/

- return (x == 0) ? MATH_NAN : 0;

+ return MATH_ISNAN(x) ? x : ((x == 0) ? MATH_NAN : 0);

}