diff --git a/libc/include/uchar.h b/libc/include/uchar.h
index ac0cf1d..e59d6a9 100644
--- a/libc/include/uchar.h
+++ b/libc/include/uchar.h
@@ -43,11 +43,11 @@
 #define __STD_UTF_16__ 1
 #define __STD_UTF_32__ 1
 
-size_t c16rtomb(char*, char16_t, mbstate_t*) __INTRODUCED_IN(21);
-size_t c32rtomb(char*, char32_t, mbstate_t*) __INTRODUCED_IN(21);
-size_t mbrtoc16(char16_t*, const char*, size_t, mbstate_t*) __INTRODUCED_IN(21);
-size_t mbrtoc32(char32_t*, const char*, size_t, mbstate_t*) __INTRODUCED_IN(21);
+size_t c16rtomb(char* __buf, char16_t __ch16, mbstate_t* __ps) __INTRODUCED_IN(21);
+size_t c32rtomb(char* __buf, char32_t __ch32, mbstate_t* __ps) __INTRODUCED_IN(21);
+size_t mbrtoc16(char16_t* __ch16, const char* __s, size_t __n, mbstate_t* __ps) __INTRODUCED_IN(21);
+size_t mbrtoc32(char32_t* __ch32, const char* __s, size_t __n, mbstate_t* __ps) __INTRODUCED_IN(21);
 
 __END_DECLS
 
-#endif /* _UCHAR_H_ */
+#endif