diff --git a/vvp/vvp_net.cc b/vvp/vvp_net.cc
index 366b19667..c181e2fb1 100644
--- a/vvp/vvp_net.cc
+++ b/vvp/vvp_net.cc
@@ -1463,8 +1463,8 @@ void vvp_fun_signal_base::recv_long(vvp_net_ptr_t ptr, long bit)
       }
 }
 
-vvp_fun_signal::vvp_fun_signal(unsigned wid)
-: bits4_(wid)
+vvp_fun_signal::vvp_fun_signal(unsigned wid, vvp_bit4_t init)
+: bits4_(wid, init)
 {
 }
 
diff --git a/vvp/vvp_net.h b/vvp/vvp_net.h
index db46c5746..31fb40509 100644
--- a/vvp/vvp_net.h
+++ b/vvp/vvp_net.h
@@ -836,7 +836,7 @@ class vvp_fun_signal_vec : public vvp_fun_signal_base {
 class vvp_fun_signal  : public vvp_fun_signal_vec {
 
     public:
-      explicit vvp_fun_signal(unsigned wid);
+      explicit vvp_fun_signal(unsigned wid, vvp_bit4_t init=BIT4_X);
 
       void recv_vec4(vvp_net_ptr_t port, const vvp_vector4_t&bit);
       void recv_vec8(vvp_net_ptr_t port, vvp_vector8_t bit);