Port Scans

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#8259

From: Max Blank
Date: Mon, 08 Nov 2004 00:21

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I need to automatically find a device connected to one of a computer's 
serial ports. This is no big deal: Simply create a file handle for each 
com port (using CreateFile), try to connect, pass the key phrase and 
wait for the correct response.

Some systems, unfortunately, use USB<->Serial adapters that work with 
19200 instead of 9600 baud. So I have to scan each port twice, don't I ?

I first try to connect at 19200 baud and fail, because no device is 
attached to this port and no handle is being created. If I try to 
connect again at 9600 baud, CreateFile cannot create a handle; however, 
if I do not try to connect at 19200, or - even more strange - when I set 
a breakpoint, stop the program's execution for less than a second, and 
continue the program, the handle is being created and the port can be 
opened !!!

So where's the problem ??


Max

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Date: Mon, 08 Nov 2004 01:21:31 +0100
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