Re: Question on select() and sockets

David Schwartz <davids@xxxxxxxxxxxxx> writes:
On Jun 9, 10:28 am, Rick Jones <rick.jon...@xxxxxx> wrote:
David Schwartz <dav...@xxxxxxxxxxxxx> wrote:
The standard does not prohibit a UDP datagram from being dropped
after it triggers a 'select' hit and before that program manages to
call 'recvmsg'.

Which standard is that?

rick jones

All of the relevant standards. POSIX, UDP, and quite a few others.

POSIX/ SUS doesn't contain definitions of particular transport
protocols. UDP is defined as a thin layer above IP, just adding a
'datagram body' with a length field, support for checksumming that,
and source and destination ports so that different applications using
UDP on a single host can as easily be supported as for TCP. This means
that UDP has all the 'transport characteristics' of IP, meaning each
datagram travels indepedently and involved devices are supposed to
make a 'best effort' attempt to further delivery. Nothing is specified
regarding behaviour of the end system after a datagram was delivered
to it.
.

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