diff --git a/libveriuser/veriusertfs.c b/libveriuser/veriusertfs.c
index 3c455b800..8807f6649 100644
--- a/libveriuser/veriusertfs.c
+++ b/libveriuser/veriusertfs.c
@@ -44,6 +44,7 @@ typedef struct t_pli_data {
 
 static PLI_INT32 compiletf(ICARUS_VPI_CONST PLI_BYTE8 *);
 static PLI_INT32 calltf(ICARUS_VPI_CONST PLI_BYTE8 *);
+static PLI_INT32 sizetf(ICARUS_VPI_CONST PLI_BYTE8 *);
 static PLI_INT32 callback(p_cb_data);
 
 /*
@@ -150,7 +151,7 @@ void veriusertfs_register_table(p_tfcell vtable)
 	    tf_data.tfname = tf->tfname;
 	    tf_data.compiletf = compiletf;
 	    tf_data.calltf = calltf;
-	    tf_data.sizetf = (PLI_INT32 (*)(ICARUS_VPI_CONST PLI_BYTE8 *))tf->sizetf;
+	    tf_data.sizetf = sizetf;
 	    tf_data.user_data = (char *)data;
 
 	    if (pli_trace) {
@@ -283,6 +284,32 @@ static PLI_INT32 calltf(ICARUS_VPI_CONST PLI_BYTE8*data)
       return rc;
 }
 
+/*
+ * This function is the wrapper for the veriusertfs sizetf routine.
+ */
+static PLI_INT32 sizetf(ICARUS_VPI_CONST PLI_BYTE8*data)
+{
+      int rc = 32;
+      p_pli_data pli;
+      p_tfcell tf;
+
+      /* cast back from opaque */
+      pli = (p_pli_data)data;
+      tf = pli->tf;
+
+      /* execute sizetf */
+      if (tf->sizetf) {
+	    if (pli_trace) {
+		  fprintf(pli_trace, "Call %s->sizetf(%d, %d)\n",
+			  tf->tfname, tf->data, reason_sizetf);
+	    }
+
+	    rc = tf->sizetf(tf->data, reason_sizetf);
+      }
+
+      return rc;
+}
+
 /*
  * This function is the wrapper for all the misctf callbacks
  */
diff --git a/veriuser.h b/veriuser.h
index 7e061c16f..7614673db 100644
--- a/veriuser.h
+++ b/veriuser.h
@@ -1,7 +1,7 @@
 #ifndef VERIUSER_H
 #define VERIUSER_H
 /*
- * Copyright (c) 2002-2014 Stephen Williams (steve@icarus.com)
+ * Copyright (c) 2002-2018 Stephen Williams (steve@icarus.com)
  *
  *    This source code is free software; you can redistribute it
  *    and/or modify it in source code form under the terms of the GNU
@@ -159,6 +159,7 @@ extern void veriusertfs_register_table(p_tfcell vtable);
 
 /* callback reasons */
 #define reason_checktf 1
+#define reason_sizetf  2
 #define reason_calltf  3
 #define reason_paramvc 7
 #define reason_synch   8