diff --git a/kinect2_viewer/src/viewer.cpp b/kinect2_viewer/src/viewer.cpp
index e6cef92d..10174cdf 100644
--- a/kinect2_viewer/src/viewer.cpp
+++ b/kinect2_viewer/src/viewer.cpp
@@ -447,7 +447,7 @@ class Receiver
       {
         register const float depthValue = *itD / 1000.0f;
         // Check for invalid measurements
-        if(isnan(depthValue) || depthValue <= 0.001)
+        if(std::isnan(depthValue) || depthValue <= 0.001)
         {
           // not valid
           itP->x = itP->y = itP->z = badPoint;