diff --git a/dlls/cfgmgr32/cfgmgr32.spec b/dlls/cfgmgr32/cfgmgr32.spec
index 9551fc0108d..efc5dbbf645 100644
--- a/dlls/cfgmgr32/cfgmgr32.spec
+++ b/dlls/cfgmgr32/cfgmgr32.spec
@@ -43,7 +43,7 @@
 @ stub CM_Free_Res_Des_Ex
 @ stub CM_Free_Res_Des_Handle
 @ stdcall CM_Get_Child(ptr long long) setupapi.CM_Get_Child
-@ stub CM_Get_Child_Ex
+@ stdcall CM_Get_Child_Ex(ptr long long ptr) setupapi.CM_Get_Child_Ex
 @ stub CM_Get_Class_Key_NameA
 @ stub CM_Get_Class_Key_NameW
 @ stub CM_Get_Class_Key_Name_ExA
diff --git a/dlls/setupapi/setupapi.spec b/dlls/setupapi/setupapi.spec
index e77369b62b1..88476d6c4b4 100644
--- a/dlls/setupapi/setupapi.spec
+++ b/dlls/setupapi/setupapi.spec
@@ -54,7 +54,7 @@
 @ stub CM_Free_Res_Des_Ex
 @ stub CM_Free_Res_Des_Handle
 @ stdcall CM_Get_Child(ptr long long)
-@ stub CM_Get_Child_Ex
+@ stdcall CM_Get_Child_Ex(ptr long long ptr)
 @ stub CM_Get_Class_Key_NameA
 @ stub CM_Get_Class_Key_NameW
 @ stub CM_Get_Class_Key_Name_ExA
diff --git a/dlls/setupapi/stubs.c b/dlls/setupapi/stubs.c
index 9b71c1c1498..a738eec25a9 100644
--- a/dlls/setupapi/stubs.c
+++ b/dlls/setupapi/stubs.c
@@ -100,6 +100,16 @@ CONFIGRET WINAPI CM_Get_Child(
     return CR_SUCCESS;
 }
 
+/***********************************************************************
+ *             CM_Get_Child_Ex  (SETUPAPI.@)
+ */
+CONFIGRET WINAPI CM_Get_Child_Ex(
+    PDEVINST pdnDevInst, DEVINST dnDevInst, ULONG ulFlags, HMACHINE hMachine)
+{
+    FIXME("%p 0x%08x 0x%08x %p: stub\n", pdnDevInst, dnDevInst, ulFlags, hMachine);
+    return CR_SUCCESS;
+}
+
 /***********************************************************************
  *             CM_Get_Device_ID_ExA  (SETUPAPI.@)
  */
diff --git a/include/cfgmgr32.h b/include/cfgmgr32.h
index 4606389b9b3..857306712eb 100644
--- a/include/cfgmgr32.h
+++ b/include/cfgmgr32.h
@@ -210,6 +210,7 @@ CMAPI CONFIGRET WINAPI CM_Locate_DevNodeW(PDEVINST,DEVINSTID_W,ULONG);
 CMAPI CONFIGRET WINAPI CM_Open_DevNode_Key(DEVINST dnDevInst, REGSAM access, ULONG ulHardwareProfile,
                                            REGDISPOSITION disposition, PHKEY phkDevice, ULONG ulFlags);
 CMAPI CONFIGRET WINAPI CM_Get_Child(PDEVINST pdnDevInst, DEVINST dnDevInst, ULONG ulFlags);
+CMAPI CONFIGRET WINAPI CM_Get_Child_Ex(PDEVINST pdnDevInst, DEVINST dnDevInst, ULONG ulFlags, HMACHINE hMachine);
 
 #ifdef __cplusplus
 }