diff --git a/dlls/sane.ds/capability.c b/dlls/sane.ds/capability.c
index 6b6867e02a6..615e4cb0b5f 100644
--- a/dlls/sane.ds/capability.c
+++ b/dlls/sane.ds/capability.c
@@ -31,6 +31,8 @@
 
 WINE_DEFAULT_DEBUG_CHANNEL(twain);
 
+static TW_UINT16 SANE_ICAPXferMech (pTW_CAPABILITY pCapability, TW_UINT16 action);
+
 TW_UINT16 SANE_SaneCapability (pTW_CAPABILITY pCapability, TW_UINT16 action)
 {
     TW_UINT16 twCC = TWCC_SUCCESS;
@@ -205,7 +207,7 @@ static TW_BOOL TWAIN_OneValueGet (pTW_CAPABILITY pCapability, TW_UINT32 *pValue)
 }
 
 /* ICAP_XFERMECH */
-TW_UINT16 SANE_ICAPXferMech (pTW_CAPABILITY pCapability, TW_UINT16 action)
+static TW_UINT16 SANE_ICAPXferMech (pTW_CAPABILITY pCapability, TW_UINT16 action)
 {
     TRACE("ICAP_XFERMECH\n");
 
diff --git a/dlls/sane.ds/sane_i.h b/dlls/sane.ds/sane_i.h
index c1f0bee1be6..badb4db980d 100644
--- a/dlls/sane.ds/sane_i.h
+++ b/dlls/sane.ds/sane_i.h
@@ -77,14 +77,6 @@ struct tagActiveDS
 /* Helper functions */
 extern TW_UINT16 SANE_SaneCapability (pTW_CAPABILITY pCapability, TW_UINT16 action);
 
-/*  */
-extern TW_UINT16 SANE_ControlGroupHandler (
-	pTW_IDENTITY pOrigin, TW_UINT16 DAT, TW_UINT16 MSG, TW_MEMREF pData);
-extern TW_UINT16 SANE_ImageGroupHandler (
-	pTW_IDENTITY pOrigin, TW_UINT16 DAT, TW_UINT16 MSG, TW_MEMREF pData);
-extern TW_UINT16 SANE_SourceManagerHandler (
-	pTW_IDENTITY pOrigin, TW_UINT16 DAT, TW_UINT16 MSG, TW_MEMREF pData);
-
 /* Implementation of operation triplets
  * From Application to Source (Control Information) */
 TW_UINT16 SANE_CapabilityGet (pTW_IDENTITY pOrigin, TW_MEMREF pData);
@@ -214,9 +206,6 @@ TW_UINT16 SANE_RGBResponseReset
 TW_UINT16 SANE_RGBResponseSet
     (pTW_IDENTITY pOrigin, TW_MEMREF pData);
 
-/* Implementation of TWAIN capabilities */
-TW_UINT16 SANE_ICAPXferMech (pTW_CAPABILITY pCapability, TW_UINT16 action);
-
 /* UI function */
 BOOL DoScannerUI(void);
 HWND ScanningDialogBox(HWND dialog, LONG progress);
diff --git a/dlls/sane.ds/sane_main.c b/dlls/sane.ds/sane_main.c
index 8c0e39feb37..ea1af0ea15e 100644
--- a/dlls/sane.ds/sane_main.c
+++ b/dlls/sane.ds/sane_main.c
@@ -372,7 +372,7 @@ static TW_UINT16 SANE_SourceControlHandler (
 }
 
 
-TW_UINT16 SANE_ImageGroupHandler (
+static TW_UINT16 SANE_ImageGroupHandler (
            pTW_IDENTITY pOrigin,
            TW_UINT16    DAT,
            TW_UINT16    MSG,