diff --git a/clib/h/wctype b/clib/h/wctype
index 3a5b45585797e661032ad965252e8c0dc944aafd..d1f14003369cb5e86f0be6252fa450a2cad236fb 100644
--- a/clib/h/wctype
+++ b/clib/h/wctype
@@ -72,7 +72,7 @@ wctype_t wctype(const char *);
 
 wint_t towlower(wint_t);
 wint_t towupper(wint_t);
-wint_t towctrans(wint_t, wtrans_t);
+wint_t towctrans(wint_t, wctrans_t);
 wctrans_t wctrans(const char *);
 
 #endif