When trying to send as many SCTP messages as possible (on Debian GNU/Linux) from TTCN3 via SCTPasp, I'm running into many log messages like this: `Warning: Sendmsg error! Strerror=Success` So "success" of course is not an err. Digging into this, it shows that 'errno' is evaluated way too late, after calling complex code that might modify errno compared to the original error. I have a patch for this specific instance (will submit a PR), but the problem seems more frequent in this codebase, so it would be good if somebody could review that. So now I see that the real error is EAGAIN (Resource temporarily unavailable). So there seems to be another bug. On a non-blocking socket, the send/sendmsg/sendto/write/... calls should of course only be called when the file descriptor is actually marked as write-able. If it is not, then -EAGAIN is returned by the kernel. So I somehow have the feeling that SCTPasp doesn't seem to handle the non-blocking sockets correctly.