How to send a file using IOCP?

Question

When using blocking sockets, all I had to do to send a file was to open the file and loop through it and send it in chunks.

But I find sending a file using overlapped sockets to be more challenging. I can think of the following approach to do it:

1. I open the file and send the first chunk, and I keep track of the file handle and file position (I store these data somewhere in memory).
2. Now when I get a completion packet indicating that some data has been sent, I retrieve the file handle and file position and send the next chunk.
3. I repeat step 2 until I reach the last chunk in the file, and then I close the file.

Is this approach correct?

Note: I don't want to use TransmitFile().

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Edit: I have updated my question.

Answer 1

Easiest way: look up 'TransmitFile' on MSDN. This functionality is so common, (eg. serving up web pages), that there is a specific API for it.

Answer 2

If you don't want to use TransmitFile() then you can use overlapped file I/O using IOCP where the completion of a file read is used to trigger a socket write and the completion of a socket write is used to trigger a file read. You then decide how much data you want in transit and issue that many file reads and wait for EOF...