diff --git a/winsup/cygwin/include/netdb.h b/winsup/cygwin/include/netdb.h
index e46e34169..91e91720d 100644
--- a/winsup/cygwin/include/netdb.h
+++ b/winsup/cygwin/include/netdb.h
@@ -228,7 +228,7 @@ void		endnetent (void);
 void		endprotoent (void);
 void		endservent (void);
 void		endrpcent  (void);
-struct hostent	*gethostbyaddr (const char *, int, int);
+struct hostent	*gethostbyaddr (const void *, socklen_t, int);
 struct hostent	*gethostbyname (const char *);
 #if __MISC_VISIBLE
 struct hostent	*gethostbyname2 (const char *, int);
diff --git a/winsup/cygwin/net.cc b/winsup/cygwin/net.cc
index fd903b112..8969e7c6f 100644
--- a/winsup/cygwin/net.cc
+++ b/winsup/cygwin/net.cc
@@ -1152,13 +1152,13 @@ cygwin_gethostbyname (const char *name)
 
 /* exported as gethostbyaddr: standards? */
 extern "C" struct hostent *
-cygwin_gethostbyaddr (const char *addr, int len, int type)
+cygwin_gethostbyaddr (const void *addr, socklen_t len, int type)
 {
   hostent *res = NULL;
 
   __try
     {
-      res = dup_ent (gethostbyaddr (addr, len, type));
+      res = dup_ent (gethostbyaddr ((const char *) addr, len, type));
       if (res)
 	debug_printf ("h_name %s", res->h_name);
       else