Daniel Stenberg wrote:
>> Right - because send(), unlike write(), doesn't return short.
>
> Nope, that's wrong. See below.
>
>> Why is it desirable to use send()/recv() rather than write()/read()?
>
> Let me quote another piece of the man page:
>
> "The only difference between send() and write(2) is the presence of flags."
Aha. But then send() will also succeed (and possibly return short) on
a socket which was predicted by select() to be writable.
Also interesting:
--8<-- Linux send(2)
If the message is too long to pass atomically through the underlying
protocol, the error EMSGSIZE is returned, and the message is not trans‐
mitted.
-->8--
This suggests that send() might have closer ties to the system TCP
parameters, while write() is more of an automated thing?
> ... and it also explains why we want to use send() and not write().
> We want the flags.
Which ones?
MSG_DONTWAIT could allow use of send() without select()ing. But if
there is a select(), there's no need for MSG_DONTWAIT.
I saw a note about MSG_NOSIGNAL in your portability notes. Is this
it? If so, why is it important?
Thanks for helping me understand better! :)
//Peter
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