diff --git a/zcancmder_protocol_basic.hpp b/zcancmder_protocol_basic.hpp
index be897fe..1752634 100644
--- a/zcancmder_protocol_basic.hpp
+++ b/zcancmder_protocol_basic.hpp
@@ -30,7 +30,7 @@
     auto* cmd = rxcmd->get_data_as<ordername##_##cmd##_t>();             \
     auto* ack = (ordername##_##ack##_t*)m_txbuf;                         \
     static_assert(sizeof(*ack) < sizeof(m_txbuf), "ack size too large"); \
-    auto     cmdheader = rxcmd->get_cmdheader();                         \
+    auto   __attribute__((unused))  cmdheader = rxcmd->get_cmdheader();                         \
     uint32_t errorcode = 0;                                              \
     if (cmd->id == varid) {                                              \
       ack->id = cmd->id;