On 2022-04-13, Ian Abbott <[email protected]> wrote: > On 13/04/2022 15:45, Grant Edwards wrote: > >> Where are the definitions for other SOL_xxxxx values (e.g. SOL_TCP) >> supposed to come from? > > Use IPPROTO_TCP instead of SOL_TCP as the "level".
Thanks, that is indeed the right answer. It appears that the other SOL_xxx values (like SOL_TCP) are a Linux feature intended to insulate the setsockopt() "level" value from the actual IP protocol numbers (e.g. IPPROTO_TCP). On Linux SOL_foo is currently the same value as IPPROTO_foo, but somebody wanted to allow for some future case where that wasn't true. Initially all of the example code Google found (and all of my old application code) used SOL_TCP. After I knew to search for setsockopt using IPPROTO_TCP, I did find a few examples (apparently for Mac OSes) that used IPPROTO_TCP instead of SOL_TCP. -- Grant _______________________________________________ lwip-users mailing list [email protected] https://lists.nongnu.org/mailman/listinfo/lwip-users
