The only exception I can think of is if the data is to be 'multicast' down 2 TCP connections...

Another exception for you: In place messaging with a "fast message" format would be nice for support. Some network hardware, including TCP via TOE cards and infiniband and the like, support very low latency messaging, e.g. < 10 microseconds. You don't want to copy, but also you don't want to serialize. In fact, for many applications you are prepared to sacrifice architecture portability on the altar of speed and you might send a contiguous c++ object, padding from alignment and all, directly as a message block. The CPU never has to see the whole object. A diminutive $0.02, Matt Hurd. IMPORTANT: The information contained in this email and/or its attachments is confidential. If you are not the intended recipient, please notify the sender immediately by reply and immediately delete this message and all its attachments. Any review, use, reproduction, disclosure or dissemination of this message or any attachment by an unintended recipient is strictly prohibited. Neither this message nor any attachment is intended as or should be construed as an offer, solicitation or recommendation to buy or sell any security or other financial instrument. Neither the sender, his or her employer nor any of their respective affiliates makes any warranties as to the completeness or accuracy of any of the information contained herein or that this message or any of its attachments is free of viruses.