Re: WaitCommEvent questions
"Dave Cullen" <email@example.com> wrote in message
Does WaitCommEvent only trigger when the control lines change in one
direction, or both directions?
It triggers whenever the value of the line changes from 0 to 1 or from 1
to 0, as far as I know.
I need to count pulses comming in on comport control lines DSR and
CTS. If the event triggers in either direction then I need a way to
determine if the line is "1" or "0". Is there a function to read
their current value?
Also, does WaitCommEvent time out if no change happens or will it hang
forever waiting for a change?
It doesn't support a timeout. But you can open a file in overlapped mode
and have WaitCommEvent run asynchronously. Then you can cancel it with
With best wishes,
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