diff --git a/cfg/windows.cfg b/cfg/windows.cfg
index 7ab06bf1b..3e27160a2 100644
--- a/cfg/windows.cfg
+++ b/cfg/windows.cfg
@@ -1752,6 +1752,17 @@
       <not-uninit/>
     </arg>
   </function>
+  <!-- BOOL GetCommMask(HANDLE  hFile, LPDWORD lpEvtMask);-->
+  <function name="GetCommMask">
+    <noreturn>false</noreturn>
+    <returnValue type="BOOL"/>
+    <arg nr="1" direction="in">
+      <not-uninit/>
+    </arg>
+    <arg nr="2" direction="out">
+      <not-null/>
+    </arg>
+  </function>
   <!-- BOOL PurgeComm(HANDLE hFile, DWORD  dwFlags);-->
   <function name="PurgeComm">
     <noreturn>false</noreturn>