Immediate IO in ReadFile / WriteFile

[Dan Kegel]

Mike McCormack wrote:
> As Lawson said, some programs use WaitForComm event to wait for data,
> then GetCommError to check how many bytes arrived, then ReadFile to
> read it. They then expect ReadFile to return TRUE.
> 
> One such program is VBTerm, the visual basic terminal program, or at
> least the VBX in it.
> 
> Testing applications that use serial ports is difficult, and debugging
> often must be done remotely. (eg. send me a trace like this, apply
> this patch and send me another trace, etc.)

For what it's worth, I documented some overlapped serial I/O quirks
some time ago at 
http://www.alumni.caltech.edu/~dank/overlap.htm
I also have a little running sample code there.

- Dan