Question About Handling the Reception of STOP_SENDING frame

[LiangLouise]

I wonder if there is any way to know the event of receiving a STOP_SENDING frame and retrieve the app_error_code.

When receiving a STOP_SENDING frame, conn_recv_stop_sending would do a lot of internal jobs, however, it doesn't have any callbacks to tell the user that some stream's sending part got shut down and provide the app_error_code.

By reading the doc and code, it seems the only way to know if a stream's sending part is shut down is by calling ngtcp2_conn_writev_stream() and getting the error value NGTCP2_ERR_STREAM_SHUT_WR. But I cannot get what the app_error_code is in STOP_SENDING in this way since it won't be provided to the user until the stream_close callback is called.

Did I miss anything?

[tatsuhiro-t]

That is the correct explanation of the current state of the art.

[LiangLouise]

Thank you for the quick reply and confirmation!

Then I guess the easiest way for me would be adding a callback to be called in conn_recv_stop_sending so it doesn't have to wait until calling ngtcp2_conn_writev_stream next time and the user code can also get back the app_error_code meanwhile.