diff --git a/include/syslevel.h b/include/syslevel.h
index 68039a0d8b4..3030183d87b 100644
--- a/include/syslevel.h
+++ b/include/syslevel.h
@@ -24,6 +24,7 @@ SEGPTR WINAPI GetpWin16Lock16(void);
 
 VOID WINAPI _EnterSysLevel(CRITICAL_SECTION *lock);
 VOID WINAPI _LeaveSysLevel(CRITICAL_SECTION *lock);
+DWORD WINAPI _ConfirmWin16Lock(void);
 
 VOID WINAPI ReleaseThunkLock(DWORD *mutex_count);
 VOID WINAPI RestoreThunkLock(DWORD mutex_count);
diff --git a/scheduler/syslevel.c b/scheduler/syslevel.c
index 297c6dfb928..5b3588eecec 100644
--- a/scheduler/syslevel.c
+++ b/scheduler/syslevel.c
@@ -123,8 +123,10 @@ VOID WINAPI _ConfirmSysLevel(CRITICAL_SECTION *lock)
  */
 DWORD WINAPI _ConfirmWin16Lock(void)
 {
-    FIXME(win32, "()\n");
-    return 1;
+    if ( Win16Mutex.OwningThread == GetCurrentThreadId() )
+        return Win16Mutex.RecursionCount;
+    else
+        return 0L;
 }
 
 /************************************************************************