Em 07-04-2016 12:19, Volker escreveu: ...
select(8, [3 7], [], [], NULL) = 1 (in [7]) recvfrom(7, 0x7ffdf3072e1b, 1, 2, 0x7ffdf3072e20, 0x7ffdf3072e1c) = -1
^--- I think that's why
EAGAIN (Resource temporarily unavailable) select(8, [3 7], [], [], NULL [...]
RHEL7 still doesn't have this patch: https://patchwork.ozlabs.org/patch/561746/
As test/workaround while that patch isn't out, please make that buffer as big as your payload, even if you're going to use only one byte. It will copy more but it's MSG_PEEK, it's not discarding/removing anything from the queue anyway. It will probably work then.
Marcelo