[ace-users] ACE_OS::sendv() behavior question concerning partial writes

Olivier Langlois Olivier.Langlois at streamtheworld.com
Fri Aug 24 11:11:58 CDT 2007


Hi Douglas,

Wow thank you for the extremely fast reply! I have not filled the problem report form because my question is not really a problem but more how ACE works in general.
>
> > My understanding of what an atomic operation is, is that it either
> > writes all the data or it does not write anything but obviously in the
> > writev() context, atomic operation means something else.
>
> Can you please provide the quote from the UNPv1 book that you're
> referring to?
>
It does not say much but here it is:

The readv and writev functions can be used with any descriptor, not just sockets. Also, writev is an atomic operation. For a record-based protocol such as UDP, one call to writev generates a single UDP datagram.

After having read the links that you have provided, I guess that "atomic operation" refers to what happens when calling writev with a datagram socket.

Thank you for the clarification!
Olivier Langlois
http://www.olivierlanglois.net



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