diff --git a/Utilities/otbossim/include/ossim/base/ossimCommon.h b/Utilities/otbossim/include/ossim/base/ossimCommon.h
index eb0ea7d95413f3225fec5188f45cb8c86ddf0851..3106b9efc1f9cd91ed87f5fe4ee8af7ec0a154f7 100644
--- a/Utilities/otbossim/include/ossim/base/ossimCommon.h
+++ b/Utilities/otbossim/include/ossim/base/ossimCommon.h
@@ -58,7 +58,7 @@ namespace ossim
      *
      * @see nan()
      */
-#if defined(WIN32) || defined(_MSC_VER) && !defined(__CYGWIN__) && !defined(__MWERKS__)
+#if (defined(WIN32) || defined(_MSC_VER)) && !defined(__CYGWIN__) && !defined(__MWERKS__)
     inline bool isnan(const float& v) { return _isnan(v); }
     inline bool isnan(const double& v) {return _isnan(v); }
 #elif defined(sun) || defined(__sun)