how to use nghttp3_conn_read_stream correctly?

[taikulawo]

nghttp3_conn_read_stream docs said.

This function returns the number of bytes consumed. Error means that conn encountered a connection error, and the connection must be closed. Calling nghttp3 API other than nghttp3_conn_del causes undefined behavior.

which means If nghttp3_conn_read_stream returns Error, we MUST stop all call to nghttp3 api in every thread except nghttp3_conn_del

But It's hard to implement in multple thread.

We do have async support for nghttp3, share Arc<Mutex<Nghttp3Connection>> to every request_stream, so every request_stream can try lock nghttp3 connection in order to call its API.

let's assume there two request_stream A,B, in different thread T1, T2

If nghttp3_conn_read_stream throw error in A|T1, it's hard to tell B/T2 to stop everything right now, never call ANY api, just return to avoid UB.

How we can nicely avoid UB on call nghttp3_conn_read_stream return error?

[tatsuhiro-t]

I had to say this is the issue of your architecture, not nghttp3. Even without nghttp3, you most likely need to stop threads or something that belong to the same connection if something bad happens with the connection.