diff --git a/libmariadb/ma_net.c b/libmariadb/ma_net.c
index 3451bf70..31e30352 100644
--- a/libmariadb/ma_net.c
+++ b/libmariadb/ma_net.c
@@ -292,7 +292,7 @@ static int ma_net_write_buff(NET *net,const char *packet, size_t len)
   return 0;
 }
 
-unsigned char *mysql_net_store_length(unsigned char *packet, size_t length);
+unsigned char *mysql_net_store_length(unsigned char *packet, ulonglong length);
 
 /*  Read and write using timeouts */
 
diff --git a/plugins/auth/my_auth.c b/plugins/auth/my_auth.c
index ce3bdd59..215f3136 100644
--- a/plugins/auth/my_auth.c
+++ b/plugins/auth/my_auth.c
@@ -12,7 +12,7 @@ static int dummy_fallback_auth_client(MYSQL_PLUGIN_VIO *vio, MYSQL *mysql __attr
 extern void read_user_name(char *name);
 extern char *ma_send_connect_attr(MYSQL *mysql, unsigned char *buffer);
 extern int ma_read_ok_packet(MYSQL *mysql, uchar *pos, ulong length);
-extern unsigned char *mysql_net_store_length(unsigned char *packet, size_t length);
+extern unsigned char *mysql_net_store_length(unsigned char *packet, ulonglong length);
 
 typedef struct {
   int (*read_packet)(struct st_plugin_vio *vio, uchar **buf);