diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index ea9a6ef22..a951d0856 100644
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -1,3 +1,7 @@
+2009-05-14  Corinna Vinschen  <corinna@vinschen.de>
+
+	* wchar.h (sys_mbstowcs): Add missing __stdcall attribute.
+
 2009-05-14  Corinna Vinschen  <corinna@vinschen.de>
 
 	* cygheap.cc (cygheap_init): Set Cygwin default locale values.
diff --git a/winsup/cygwin/wchar.h b/winsup/cygwin/wchar.h
index 4c720cbc8..fc8eb3858 100644
--- a/winsup/cygwin/wchar.h
+++ b/winsup/cygwin/wchar.h
@@ -59,7 +59,7 @@ size_t __stdcall sys_wcstombs_alloc (char **, int, const wchar_t *,
 size_t __stdcall sys_cp_mbstowcs (mbtowc_p, char *, wchar_t *, size_t,
 				  const char *, size_t = (size_t) -1)
        __attribute__ ((regparm(3)));
-size_t sys_mbstowcs (wchar_t * dst, size_t dlen, const char *src,
+size_t __stdcall sys_mbstowcs (wchar_t * dst, size_t dlen, const char *src,
 		     size_t nms = (size_t) -1)
        __attribute__ ((regparm(3)));
 size_t __stdcall sys_mbstowcs_alloc (wchar_t **, int, const char *,