Windows System Programming Third Edition

354

CHAPTER 12 NETWORK PROGRAMMING WITH WINDOWS SOCKETS

The return value is the actual number of bytes transmitted. An error is

indicated by the value

.

can be used to indicate urgency (such as out-of-band data), and

can be used to look at incoming data without read ing it.

The most important fact to remember is that

and are not atomic,

and there is no assurance that all the requested data has been received or sent.

“ Short sends” are extremely rare but possible, as are “short receives.” There is no

concept of a message as with named pipes; therefore, you need to test the return

value and resend or transmit until all data

has been transmitted.