Is there a way to block on a socket send() until we get the ack for that packet?

Question

Or do I have to implement it at the application level?

Answer 1

Why not just use a blocking socket?

This may be a bit dated, but here is some explanation on blocking/non-blocking and overlapping IO.

http://support.microsoft.com/kb/181611

It would help if we knew which language and OS you were using, BTW, to better show code snippets.