you should call GetOverlappedResult or inspect the now documented members of the OVERLAPPED struct to determine the result of your request
Thanks
Mr. Tim_Roberts and Mr. MBond2. What do you think. Will writing the driver in assembly language (instead of C) will increase the performance?. In 1995 we compared and got about 1.5 (Turbo C and assembler).
Now on my computer I have about 27 for upload and the same for download without my driver. When I push my filter driver into the network stack it is 26.26. It’s good or try to write on assembler.
No. Optimizing compilers have improved to the point that they can outperform all but the most elite assembler experts. I consider myself to be an expert, but I haven’t written an assembler module in more than a decade.
if your code is expected to run on one specific hardware configuration, and you have a LOT of time on your hands, you might be able to hand craft assembly code that out performs the MSVC emitted code. But you need both the certainty of the hardware platform and the sublime skill of a savant to do better. And even if you do, it will not represent an order of magnitude gain, but at most a few percentage points
Certianty of hardware is a VERY important factor. Hardly anyone ever has this. Aerospace and medical applications might, but any commodity hardware never does. And the averages built into optimizers are usually better than hand crafted solutions - especially since the hardware guys optimize the hardware for the commonly emitted patterns
Thank You Mr. Tim_Roberts and Mr. MBond2. I’ve stopped thinking about writing a driver in a lower level language and will try to write a driver for a USB “data converter” to call it from the NDIS Filter driver, instead of sending the data to the user mode and calling the convert function on the USB device there. I think, it will increase performance significantly.