diff --git a/icu4c/source/test/intltest/datamap.cpp b/icu4c/source/test/intltest/datamap.cpp
index 8d0e0392df..77ca0b5169 100644
--- a/icu4c/source/test/intltest/datamap.cpp
+++ b/icu4c/source/test/intltest/datamap.cpp
@@ -21,10 +21,12 @@ DataMap::utoi(const UnicodeString &s) const
   return atoi(ch);
 }
 
-
-void deleteResBund(void *obj) {
+U_CDECL_BEGIN
+void U_CALLCONV
+deleteResBund(void *obj) {
   delete (ResourceBundle *)obj;
 }
+U_CDECL_END
 
 
 RBDataMap::~RBDataMap()