diff --git a/libc/include/bits/wctype.h b/libc/include/bits/wctype.h
index 0015261e9..3abbf828f 100644
--- a/libc/include/bits/wctype.h
+++ b/libc/include/bits/wctype.h
@@ -54,12 +54,12 @@ wint_t towlower(wint_t __wc);
 wint_t towupper(wint_t __wc);
 
 typedef long wctype_t;
-wctype_t wctype(const char* __name);
+wctype_t wctype(const char* _Nonnull __name);
 int iswctype(wint_t __wc, wctype_t __type);
 
 typedef const void* wctrans_t;
-wint_t towctrans(wint_t __wc, wctrans_t __transform) __INTRODUCED_IN_NO_GUARD_FOR_NDK(26);
-wctrans_t wctrans(const char* __name) __INTRODUCED_IN_NO_GUARD_FOR_NDK(26);
+wint_t towctrans(wint_t __wc, wctrans_t _Nonnull __transform) __INTRODUCED_IN_NO_GUARD_FOR_NDK(26);
+wctrans_t _Nullable wctrans(const char* _Nonnull __name) __INTRODUCED_IN_NO_GUARD_FOR_NDK(26);
 
 __END_DECLS