diff --git a/libc/include/wchar.h b/libc/include/wchar.h
index e2feb60..97e1b5c 100644
--- a/libc/include/wchar.h
+++ b/libc/include/wchar.h
@@ -100,6 +100,7 @@
 extern size_t            mbrlen(const char *, size_t, mbstate_t *);
 extern size_t            mbrtowc(wchar_t *, const char *, size_t, mbstate_t *);
 extern size_t            mbsrtowcs(wchar_t *, const char **, size_t, mbstate_t *);
+extern size_t            mbstowcs(wchar_t *, const char *, size_t);
 extern wint_t            putwc(wchar_t, FILE *);
 extern wint_t            putwchar(wchar_t);
 extern int               swprintf(wchar_t *, size_t, const wchar_t *, ...);
@@ -130,6 +131,7 @@
 extern double            wcstod(const wchar_t *, wchar_t **);
 extern wchar_t          *wcstok(wchar_t *, const wchar_t *, wchar_t **);
 extern long int          wcstol(const wchar_t *, wchar_t **, int);
+extern size_t            wcstombs(char *, const wchar_t *, size_t);
 extern unsigned long int wcstoul(const wchar_t *, wchar_t **, int);
 extern wchar_t          *wcswcs(const wchar_t *, const wchar_t *);
 extern int               wcswidth(const wchar_t *, size_t);