diff --git a/src/libCom/cxxTemplates/epicsSingleton.h b/src/libCom/cxxTemplates/epicsSingleton.h
index 0e1d0f9db..1c56fd41f 100644
--- a/src/libCom/cxxTemplates/epicsSingleton.h
+++ b/src/libCom/cxxTemplates/epicsSingleton.h
@@ -105,7 +105,7 @@ inline epicsSingleton<TYPE>::~epicsSingleton ()
 }
 
 // SUN PRO generates warnings unless it sees an implementation
-#ifdef _SUNPRO_C
+#ifdef _SUNPRO_CC
     template < class TYPE >
     inline epicsSingleton<TYPE>::epicsSingleton ( const epicsSingleton & )
     {