diff --git a/icu4c/source/test/cintltst/custrtst.c b/icu4c/source/test/cintltst/custrtst.c
index e790b19521..31d388e68f 100644
--- a/icu4c/source/test/cintltst/custrtst.c
+++ b/icu4c/source/test/cintltst/custrtst.c
@@ -33,6 +33,7 @@
 
 /* test setup --------------------------------------------------------------- */
 
+static void setUpDataTable(void);
 static void TestStringCopy(void);
 static void TestStringFunctions(void);
 static void TestStringSearching(void);