diff --git a/dlls/msvcr80/msvcr80.spec b/dlls/msvcr80/msvcr80.spec
index 02ecbfc..eb2f474 100644
--- a/dlls/msvcr80/msvcr80.spec
+++ b/dlls/msvcr80/msvcr80.spec
@@ -1054,9 +1054,9 @@
 @ cdecl _vsnprintf_s(ptr long long str ptr) msvcrt._vsnprintf_s
 @ cdecl _vsnprintf_s_l(ptr long long str ptr ptr) msvcrt._vsnprintf_s_l
 @ cdecl _vsnwprintf(ptr long wstr ptr) msvcrt._vsnwprintf
-@ stub _vsnwprintf_l
-@ stub _vsnwprintf_s
-@ stub _vsnwprintf_s_l
+@ cdecl _vsnwprintf_l(ptr long wstr ptr ptr) msvcrt._vsnwprintf_l
+@ cdecl _vsnwprintf_s(ptr long long wstr ptr) msvcrt._vsnwprintf_s
+@ cdecl _vsnwprintf_s_l(ptr long long wstr ptr ptr) msvcrt._vsnwprintf_s_l
 @ stub _vsprintf_l
 @ stub _vsprintf_p
 @ stub _vsprintf_p_l
diff --git a/dlls/msvcr90/msvcr90.spec b/dlls/msvcr90/msvcr90.spec
index 5814fb2..7ffb0b9 100644
--- a/dlls/msvcr90/msvcr90.spec
+++ b/dlls/msvcr90/msvcr90.spec
@@ -1041,9 +1041,9 @@
 @ cdecl _vsnprintf_s(ptr long long str ptr) msvcrt._vsnprintf_s
 @ cdecl _vsnprintf_s_l(ptr long long str ptr ptr) msvcrt._vsnprintf_s_l
 @ cdecl _vsnwprintf(ptr long wstr ptr) msvcrt._vsnwprintf
-@ stub _vsnwprintf_l
-@ stub _vsnwprintf_s
-@ stub _vsnwprintf_s_l
+@ cdecl _vsnwprintf_l(ptr long wstr ptr ptr) msvcrt._vsnwprintf_l
+@ cdecl _vsnwprintf_s(ptr long long wstr ptr) msvcrt._vsnwprintf_s
+@ cdecl _vsnwprintf_s_l(ptr long long wstr ptr ptr) msvcrt._vsnwprintf_s_l
 @ stub _vsprintf_l
 @ stub _vsprintf_p
 @ stub _vsprintf_p_l
diff --git a/dlls/msvcrt/msvcrt.h b/dlls/msvcrt/msvcrt.h
index 81b0f4b..8d66eef 100644
--- a/dlls/msvcrt/msvcrt.h
+++ b/dlls/msvcrt/msvcrt.h
@@ -738,7 +738,7 @@
 MSVCRT_FILE*   __cdecl MSVCRT__fdopen(int, const char *);
 MSVCRT_FILE*   __cdecl MSVCRT__wfdopen(int, const MSVCRT_wchar_t *);
 int            __cdecl MSVCRT_vsnprintf(char *str, MSVCRT_size_t len, const char *format, __ms_va_list valist);
-int            __cdecl MSVCRT_vsnwprintf(MSVCRT_wchar_t *str, unsigned int len,
+int            __cdecl MSVCRT_vsnwprintf(MSVCRT_wchar_t *str, MSVCRT_size_t len,
                                        const MSVCRT_wchar_t *format, __ms_va_list valist );
 int            __cdecl MSVCRT_raise(int sig);
 
diff --git a/dlls/msvcrt/msvcrt.spec b/dlls/msvcrt/msvcrt.spec
index a7070df..59ed3b3 100644
--- a/dlls/msvcrt/msvcrt.spec
+++ b/dlls/msvcrt/msvcrt.spec
@@ -983,9 +983,9 @@
 @ cdecl _vsnprintf_s(ptr long long str ptr) MSVCRT_vsnprintf_s
 @ cdecl _vsnprintf_s_l(ptr long long str ptr ptr) MSVCRT_vsnprintf_s_l
 @ cdecl _vsnwprintf(ptr long wstr ptr) MSVCRT_vsnwprintf
-# stub _vsnwprintf_l
-# stub _vsnwprintf_s
-# stub _vsnwprintf_s_l
+@ cdecl _vsnwprintf_l(ptr long wstr ptr ptr) MSVCRT_vsnprintf_l
+@ cdecl _vsnwprintf_s(ptr long long wstr ptr) MSVCRT_vsnprintf_s
+@ cdecl _vsnwprintf_s_l(ptr long long wstr ptr ptr) MSVCRT_vsnprintf_s_l
 # stub _vsprintf_l
 # stub _vsprintf_p
 # stub _vsprintf_p_l
diff --git a/dlls/msvcrt/wcs.c b/dlls/msvcrt/wcs.c
index 4ebb0e0..652cbd7 100644
--- a/dlls/msvcrt/wcs.c
+++ b/dlls/msvcrt/wcs.c
@@ -935,10 +935,11 @@
 }
 
 /*********************************************************************
- *		_vsnwsprintf (MSVCRT.@)
+ * vsnwsprintf_internal (INTERNAL)
  */
-int CDECL MSVCRT_vsnwprintf( MSVCRT_wchar_t *str, unsigned int len,
-                             const MSVCRT_wchar_t *format, __ms_va_list valist )
+static inline int vsnwprintf_internal(MSVCRT_wchar_t *str, MSVCRT_size_t len,
+        const MSVCRT_wchar_t *format, MSVCRT__locale_t locale, BOOL valid,
+        __ms_va_list valist)
 {
     pf_output out;
 
@@ -947,7 +948,65 @@
     out.used = 0;
     out.len = len;
 
-    return pf_vsnprintf( &out, format, NULL, FALSE, valist );
+    return pf_vsnprintf( &out, format, locale, valid, valist );
+}
+
+/*********************************************************************
+ *              _vsnwsprintf (MSVCRT.@)
+ */
+int CDECL MSVCRT_vsnwprintf(MSVCRT_wchar_t *str, MSVCRT_size_t len,
+        const MSVCRT_wchar_t *format, __ms_va_list valist)
+{
+    return vsnwprintf_internal(str, len, format, NULL, FALSE, valist);
+}
+
+/*********************************************************************
+ *              _vsnwsprintf_l (MSVCRT.@)
+ */
+int CDECL MSVCRT_vsnwprintf_l(MSVCRT_wchar_t *str, MSVCRT_size_t len,
+        const MSVCRT_wchar_t *format, MSVCRT__locale_t locale,
+        __ms_va_list valist)
+{
+        return vsnwprintf_internal(str, len, format, locale, FALSE, valist);
+}
+
+/*********************************************************************
+ *              _vsnwsprintf_s_l (MSVCRT.@)
+ */
+int CDECL MSVCRT_vsnwprintf_s_l( MSVCRT_wchar_t *str, MSVCRT_size_t sizeOfBuffer,
+        MSVCRT_size_t count, const MSVCRT_wchar_t *format,
+        MSVCRT__locale_t locale, __ms_va_list valist)
+{
+    int len, ret;
+
+    len = sizeOfBuffer/sizeof(MSVCRT_wchar_t);
+    if(count!=-1 && len>count+1)
+        len = count+1;
+
+    ret = vsnwprintf_internal(str, len, format, locale, TRUE, valist);
+
+    if(ret<0 || ret==len) {
+        if(count!=_TRUNCATE && count>sizeOfBuffer/sizeof(MSVCRT_wchar_t)) {
+            MSVCRT__invalid_parameter( NULL, NULL, NULL, 0, 0 );
+            *MSVCRT__errno() = MSVCRT_ERANGE;
+            memset(str, 0, sizeOfBuffer);
+        } else
+            str[len-1] = '\0';
+
+        return -1;
+    }
+
+    return ret;
+}
+
+/*********************************************************************
+ *              _vsnwsprintf_s (MSVCRT.@)
+ */
+int CDECL MSVCRT_vsnwprintf_s(MSVCRT_wchar_t *str, MSVCRT_size_t sizeOfBuffer,
+        MSVCRT_size_t count, const MSVCRT_wchar_t *format, __ms_va_list valist)
+{
+    return MSVCRT_vsnwprintf_s_l(str, sizeOfBuffer, count,
+            format, NULL, valist);
 }
 
 /*********************************************************************