diff --git a/src/func.cc b/src/func.cc
index 6001475f..f96157f0 100644
--- a/src/func.cc
+++ b/src/func.cc
@@ -646,11 +646,11 @@ Value builtin_cross(const Context *, const EvalContext *evalctx)
 		}
 		double d0 = v0[a].toDouble();
 		double d1 = v1[a].toDouble();
-		if (isnan(d0) || isnan(d1)) {
+		if (boost::math::isnan(d0) || boost::math::isnan(d1)) {
 			PRINT("WARNING: Invalid value (NaN) in parameter vector for cross()");
 			return Value();
 		}
-		if (isinf(d0) || isinf(d1)) {
+		if (boost::math::isinf(d0) || boost::math::isinf(d1)) {
 			PRINT("WARNING: Invalid value (INF) in parameter vector for cross()");
 			return Value();
 		}
diff --git a/src/primitives.cc b/src/primitives.cc
index cebc0314..f3c66fcd 100644
--- a/src/primitives.cc
+++ b/src/primitives.cc
@@ -42,7 +42,7 @@
 using namespace boost::assign; // bring 'operator+=()' into scope
 
 #include <boost/math/special_functions/fpclassify.hpp>
-using boost::math::isinf;
+#define isinf boost::math::isinf
 
 #define F_MINIMUM 0.01
 
diff --git a/src/value.cc b/src/value.cc
index af2a4b42..00249cc0 100644
--- a/src/value.cc
+++ b/src/value.cc
@@ -40,8 +40,6 @@
 #include <glib.h>
 
 #include <boost/math/special_functions/fpclassify.hpp>
-using boost::math::isnan;
-using boost::math::isinf;
 
 std::ostream &operator<<(std::ostream &stream, const Filename &filename)
 {
@@ -646,11 +644,11 @@ void Value::RangeType::normalize() {
 }
 
 uint32_t Value::RangeType::nbsteps() const {
-  if (isnan(step_val) || isinf(begin_val) || (isinf(end_val))) {
+  if (boost::math::isnan(step_val) || boost::math::isinf(begin_val) || (boost::math::isinf(end_val))) {
     return std::numeric_limits<uint32_t>::max();
   }
 
-  if ((begin_val == end_val) || isinf(step_val)) {
+  if ((begin_val == end_val) || boost::math::isinf(step_val)) {
     return 0;
   }