adding modbus_send_raw_request_tid

Author: cedricboudinet

src/modbus.c

@@ -220,7 +220,7 @@ static int send_msg(modbus_t *ctx, uint8_t *msg, int msg_length)
     return rc;
 }
 
-int modbus_send_raw_request(modbus_t *ctx, const uint8_t *raw_req, int raw_req_length)
+int modbus_send_raw_request_tid(modbus_t *ctx, const uint8_t *raw_req, int raw_req_length, long tid)
 {
     sft_t sft;
     uint8_t req[MAX_MESSAGE_LENGTH];
@@ -242,7 +242,7 @@ int modbus_send_raw_request(modbus_t *ctx, const uint8_t *raw_req, int raw_req_l
     sft.slave = raw_req[0];
     sft.function = raw_req[1];
     /* The t_id is left to zero */
-    sft.t_id = 0;
+    sft.t_id = tid;
     /* This response function only set the header so it's convenient here */
     req_length = ctx->backend->build_response_basis(&sft, req);
 
@@ -255,6 +255,11 @@ int modbus_send_raw_request(modbus_t *ctx, const uint8_t *raw_req, int raw_req_l
     return send_msg(ctx, req, req_length);
 }
 
+int modbus_send_raw_request(modbus_t *ctx, const uint8_t *raw_req, int raw_req_length)
+{
+    return modbus_send_raw_request_tid(ctx, raw_req, raw_req_length, 0);
+}
+
 /*
  *  ---------- Request     Indication ----------
  *  | Client | ---------------------->| Server |

src/modbus.h

@@ -257,6 +257,9 @@ MODBUS_API void modbus_mapping_free(modbus_mapping_t *mb_mapping);
 MODBUS_API int
 modbus_send_raw_request(modbus_t *ctx, const uint8_t *raw_req, int raw_req_length);
 
+MODBUS_API int
+modbus_send_raw_request_tid(modbus_t *ctx, const uint8_t *raw_req, int raw_req_length, long tid);
+
 MODBUS_API int modbus_receive(modbus_t *ctx, uint8_t *req);
 
 MODBUS_API int modbus_receive_confirmation(modbus_t *ctx, uint8_t *rsp);