diff --git a/src/mlpack/methods/kmeans/kmeans_impl.hpp b/src/mlpack/methods/kmeans/kmeans_impl.hpp
index c3254b3..20681cc 100644
--- a/src/mlpack/methods/kmeans/kmeans_impl.hpp
+++ b/src/mlpack/methods/kmeans/kmeans_impl.hpp
@@ -175,7 +175,7 @@ Cluster(const MatType& data,
     iteration++;
     Log::Info << "KMeans::Cluster(): iteration " << iteration << ", residual "
         << cNorm << ".\n";
-    if (isnan(cNorm) || isinf(cNorm))
+    if (std::isnan(cNorm) || std::isinf(cNorm))
       cNorm = 1e-4; // Keep iterating.
 
   } while (cNorm > 1e-5 && iteration != maxIterations);