> For the complete documentation index, see [llms.txt](https://mwx.twelite.info/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mwx.twelite.info/latest_en/api-reference/sys_callbacks/on_tx_comp.md).

# on\_tx\_comp()

Called when transmission is complete.

```cpp
void on_tx_comp(mwx::packet_ev_tx& ev, bool_t &b_handled) 
```

This function is called from within the MWX library with data stored in `ev` as `packet_ev_tx` when the wireless packet transmission is finished. If this function is not defined in the application, a weak function that does nothing is linked.

`ev.u8CbId` is the ID at the time of transmission and `ev.bStatus` is a flag indicating success (1) or failure (0) of the transmission.

Setting `b_handled` to *true* in this function tells the MWX library that the incoming packet has been processed in the application. If set to *processed*, it suppresses unnecessary processing. (Do not call event callback functions for `the_twelite.app`, `.board`, or `.settings`)