Hi Dick, --- BRIDGES Dick <Dick.Bridges@us.thalesgroup.com> wrote:
<use_case truncated="yes"> I have done some message passing over TCP where the message headers can be fairly elaborate and there is considerable variation in message size (e.g., DIAMETER RFC 3588). Every time some traffic arrives, one of two questions get asked: "Did we get enough of the header to determine the message length?" or "Given we know the length, do we have the entire message yet?". It would be nice to move this code (and all of the associated anomaly handling) out of the application and *down* into the library. read_at_least_n would certainly be handy. </use_case>
As a generalization, I'd say that those two questions get asked almost anytime discrete messages are passed over a stream protocol.
Your comments resulted in a small amount of inspiration :) The _at_least_n functionality has been retained in 0.3.5 through an additional function object argument to asio::read()/write() etc. In practice this means that where you used to write: asio::read_at_least_n(s, bufs, 42, handler); you now write: asio::read(s, bufs, asio::transfer_at_least(42)); Cheers, Chris