diff --git a/ext2spice/ext2hier.c b/ext2spice/ext2hier.c
index e2204ae8..7b817c7c 100644
--- a/ext2spice/ext2hier.c
+++ b/ext2spice/ext2hier.c
@@ -1325,12 +1325,16 @@ spccapHierVisit(
  *
  * ----------------------------------------------------------------------------
  */
+
+/*ARGUSED*/
+/* @typedef cb_extflat_hiervisitresists_t (UNUSED) */
 int
 spcresistHierVisit(
     HierContext *hc,
-    HierName *hierName1,
-    HierName *hierName2,
-    float res)
+    const HierName *hierName1,
+    const HierName *hierName2,
+    float res,
+    ClientData cdata)	// UNUSED
 {
     HashEntry *he;
     EFNodeName *nn;
@@ -2213,7 +2217,7 @@ esHierVisit(
 	EFHierVisitDevs(hcf, spcdevHierVisit, PTR2CD(NULL));
 
 	/* Output lumped parasitic resistors */
-	EFHierVisitResists(hcf, spcresistHierVisit, (ClientData)NULL);
+	EFHierVisitResists(hcf, spcresistHierVisit, PTR2CD(NULL));
 
 	/* Output coupling capacitances */
 	EFHierVisitCaps(hcf, spccapHierVisit, (ClientData)NULL);
diff --git a/extflat/EFhier.c b/extflat/EFhier.c
index 25e1abea..380ec3dc 100644
--- a/extflat/EFhier.c
+++ b/extflat/EFhier.c
@@ -559,13 +559,15 @@ efHierVisitSingleResist(hc, name1, name2, res, ca)
  * Visit all the resistors in the circuit.
  * For each resistor in the circuit, call the user-supplied procedure
  * (*resProc)(), which should be of the following form, where hn1 and
- * hn2 are the HierNames of the two nodes connected by the resistor.
+ * hn2 are the HierNames of the two nodes connected by the resistor
+ *   see also typedef cb_extflat_hiervisitresists_t:
  *
- *	(*resProc)(hc, hn1, hn2, resistance, cdata)
- *	    HierContext *hc;
- *	    HierName *hn1, *hn2;
- *	    int resistance;
- *	    ClientData cdata;
+ *	int (*resProc)(
+ *	    HierContext *hc,
+ *	    const HierName *hierName1,
+ *	    const HierName *hierName2,
+ *	    float resistance,
+ *	    ClientData cdata)
  *	{
  *	}
  *
@@ -586,15 +588,15 @@ efHierVisitSingleResist(hc, name1, name2, res, ca)
  */
 
 int
-EFHierVisitResists(hc, resProc, cdata)
-    HierContext *hc;
-    int (*resProc)();
-    ClientData cdata;
+EFHierVisitResists(
+    HierContext *hc,
+    const cb_extflat_hiervisitresists_t resProc,
+    ClientData cdata)
 {
     CallArg ca;
     int efHierVisitResists();	/* Forward reference */
 
-    ca.ca_proc = resProc;
+    ca.ca_proc = (int (*)()) resProc;
     ca.ca_cdata = cdata;
     return efHierVisitResists(hc, (ClientData) &ca);
 }
@@ -630,7 +632,7 @@ efHierVisitResists(hc, ca)
 			res, ca))
 		return 1;
 	}
-	else if (efHierSrArray(hc, res, efHierVisitSingleResist, (ClientData) ca))
+	else if (efHierSrArray(hc, res, efHierVisitSingleResist, PTR2CD(ca)))
 	    return 1;
     }
     return 0;
diff --git a/extflat/extflat.h b/extflat/extflat.h
index 6fd3ac81..a940ad48 100644
--- a/extflat/extflat.h
+++ b/extflat/extflat.h
@@ -130,7 +130,8 @@ extern int  EFVisitSubcircuits();
 extern int  EFHierVisitSubcircuits();
 typedef int (*cb_extflat_hiervisitdevs_t)(HierContext *hc, Dev *dev, float scale, ClientData cdata);
 extern int EFHierVisitDevs(HierContext *hc, const cb_extflat_hiervisitdevs_t devProc, ClientData cdata);
-extern int  EFHierVisitResists();
+typedef int (*cb_extflat_hiervisitresists_t)(HierContext *hc, const HierName *hierName1, const HierName *hierName2, float resistance, ClientData cdata);
+extern int EFHierVisitResists(HierContext *hc, const cb_extflat_hiervisitresists_t resProc, ClientData cdata);
 extern int  EFHierVisitCaps();
 extern int  EFHierVisitNodes();