ReadFile behaviour on COMs

[Uwe Bonnes]

Hallo,

somebody showed me an application speaking to a device connected to the
serial port. The application failed after some successfull communication
steps. As the protocoll is available in some other (open source programm) we
could see that the program requested two bytes from the device , but
ReadFile only delivered one byte (with that byte beeing the right one of the
expected two byte sequence).

I suspect ReadFile to be the culprit. While the api description tells to
read all requested bytes ( beside of real errors), our implementation
happilies returns fewer bytes than requested. In the case of COM devices,
all timeouts of the SetCommTimeout structure should be checked two.

Anyone with an implementaion for that?

Bye