diff --git a/src/libCom/osi/os/posix/epicsMath.h b/src/libCom/osi/os/posix/epicsMath.h
index 13f25e520..a8e9b815f 100644
--- a/src/libCom/osi/os/posix/epicsMath.h
+++ b/src/libCom/osi/os/posix/epicsMath.h
@@ -15,12 +15,14 @@
 
 #ifdef __cplusplus
 
+#if __cplusplus>=201103L
 #include <cmath>
 
 using std::isfinite;
 using std::isinf;
 using std::isnan;
 using std::isnormal;
+#endif
 
 extern "C" {
 #endif