diff --git a/util/ddv_socket.cpp b/util/ddv_socket.cpp
index e7b6c099..0f26d36c 100644
--- a/util/ddv_socket.cpp
+++ b/util/ddv_socket.cpp
@@ -94,7 +94,7 @@ int DDV_Accept(int sock, bool nonblock = false){
   return r;
 }
 
-bool DDV_write(void * buffer, int todo, int sock){
+bool DDV_write(const void * buffer, int todo, int sock){
   int sofar = 0;
   socketBlocking = false;
   while (sofar != todo){