From: "Iain K. Hanson" <ikh@hansons.demon.co.uk>
On Tue, Apr 26, 2005 at 02:31:43AM +0300, Boris wrote:
However I withdraw the idea of non-blocking I/O support in socket streams anyway as we can't know with the standard interface if "s << a" fails partially.
Whether it is non-blocking or not is AFAICS is irrelevant. if is sizeof char then a is not in the buffer and the failure is because of buffer write. if a is > size of char then some part of a is in the buffer upto the point that the buffer overflows. If you know the sizeof the buffer, where you are in the buffer and the size of a then you know how much of a is in the buffer.
Async is an issue because you have to deal with the EWOULDBLOCK condition. However, you are raising a new issue regarding the possibility that an internal buffer of the data to be written on the socket can't be written. That can mean that a portion of an object written with << will be in the buffer, but there's no way to know which portion. Have I got your point right?
However, only a fool would allow the buffer to overflow across a single <<.
Statements like this aren't helpful. Try, "The mistake is allowing the buffer to overflow across a single <<." And then follow it up with guidance on the approach that should be taken. -- Rob Stewart stewart@sig.com Software Engineer http://www.sig.com Susquehanna International Group, LLP using std::disclaimer;