Suggest, try to run you same application with this issue on Linux. I'm expecting at least a similar error on Linux.
BR, Alan On 6/18/23, Alan C. Assis <acas...@gmail.com> wrote: > Hi Fotis, > > On 6/18/23, Fotis Panagiotopoulos <f.j.pa...@gmail.com> wrote: >> Hello, >> >> Due to a bug in my application, the code tried to use sendfile() with >> zero >> size. >> >> As I see, sendfile() will happily proceed, and it will block here: >> https://github.com/apache/nuttx/blob/master/net/tcp/tcp_sendfile.c#L523 >> >> Obviously, it will never manage to send any data (as the requested size >> is >> 0), >> and after the timeout expires, it will return EAGAIN. >> > > Good finding! > > BTW, that is the default timeout value? > > I think conn->sconn.s_sndtimeo is only defined when people enable the > CONFIG_NET_SOCKOPTS. > >> This seems a bit wrong to me. >> Why not return immediately, but instead wait for the (inevitable) >> timeout? >> Why not return a more meaningful error code, or maybe just 0? >> > > I was going to suggest avoid sending a packet with 0 byte, but it is > supported: > https://www.quora.com/Can-TCP-send-0-byte-packets > https://github.com/golang/go/issues/10940 > > See, technically it is not an error! :-) > >> I couldn't find what the standards dictate for this edge case, so maybe >> the >> current behavior is correct. >> >> What do you think? >> > > I think it is correct, but most servers will just ignore it and you > will end-up with a timeout. > > BR, > > Alan >
