diff --git a/dlls/dinput/device.c b/dlls/dinput/device.c
index ead1052d0a2..a4052ea4e24 100644
--- a/dlls/dinput/device.c
+++ b/dlls/dinput/device.c
@@ -570,7 +570,7 @@ int find_property(const DataFormat *df, LPCDIPROPHEADER ph)
     return -1;
 }
 
-DWORD semantic_to_obj_id(IDirectInputDeviceImpl* This, DWORD dwSemantic)
+static DWORD semantic_to_obj_id(IDirectInputDeviceImpl* This, DWORD dwSemantic)
 {
     DWORD type = (0x0000ff00 & dwSemantic) >> 8;
     DWORD offset = 0x000000ff & dwSemantic;
diff --git a/dlls/dinput/device_private.h b/dlls/dinput/device_private.h
index 347c6420a97..660ebd73267 100644
--- a/dlls/dinput/device_private.h
+++ b/dlls/dinput/device_private.h
@@ -124,7 +124,6 @@ extern void _dump_OBJECTINSTANCEW(const DIDEVICEOBJECTINSTANCEW *ddoi)  DECLSPEC
 extern void _dump_DIDATAFORMAT(const DIDATAFORMAT *df)  DECLSPEC_HIDDEN;
 extern const char *_dump_dinput_GUID(const GUID *guid)  DECLSPEC_HIDDEN;
 
-extern DWORD semantic_to_obj_id(IDirectInputDeviceImpl* This, DWORD dwSemantic)  DECLSPEC_HIDDEN;
 extern LPDIOBJECTDATAFORMAT dataformat_to_odf_by_type(LPCDIDATAFORMAT df, int n, DWORD type)   DECLSPEC_HIDDEN;
 
 extern HRESULT _build_action_map(LPDIRECTINPUTDEVICE8W iface, LPDIACTIONFORMATW lpdiaf, LPCWSTR lpszUserName, DWORD dwFlags, DWORD devMask, LPCDIDATAFORMAT df)  DECLSPEC_HIDDEN;