Serial port problems.

[George Kulz]

Hi all.

I have a program set up that simply monitors the serial port, with no timeout.
Every time it receives 7 bytes in succession, it parses the "message" received
and displays the data in appropriate fields on the screen. I have a class
called CSerialIO which is derived from the CFile class. A function called
OpenCOM sets up communication on the port and then kicks off a thread which
sits in a read loop. Everything runs fine until I go to close the dialog
box. When attempting to close the communication, however, the application
hangs because the read thread is sitting at the Read command waiting for
input from the serial port. It is unable to process any thread messages
while it is sitting there, so it cannot shut itself down. Does anyone know
how I might be able to force the thread to process messages? Or somehow
force a return from the Read command? Any help would be appreciated.

-George Kulz, Senior Software Engineer
PowerSmart Inc.

----------------------

The views expressed here are mine and do not reflect the official position
of my employer, or the organization through which the Internet was accessed.

[Patrick Toohey]

George,

The thread can be terminated in four different ways. The best method is for
the thread to return on its own. This ensures all objects within the thread
have called their destructors, as well as other OS cleanup. If this is not
possible, the thread can kill itself with the ExitThread function or another
thread can kill it with the TerminateThread function. Finally if the process
containing the thread terminates, the thread itself will also be terminated.
This sounds like your case, so I don't see why the thread is not terminated
unwillingly. If you are terminating the application all together, windows
will perform any clean up for you, so killing the thread is the quick and
dirty way to exit.

"George Kulz" <gkulz@powersmart.com> wrote:
>
>Hi all.
>
>I have a program set up that simply monitors the serial port, with no timeout.
> Every time it receives 7 bytes in succession, it parses the "message" received
>and displays the data in appropriate fields on the screen. I have a class
>called CSerialIO which is derived from the CFile class. A function called
>OpenCOM sets up communication on the port and then kicks off a thread which
>sits in a read loop. Everything runs fine until I go to close the dialog
>box. When attempting to close the communication, however, the application
>hangs because the read thread is sitting at the Read command waiting for
>input from the serial port. It is unable to process any thread messages
>while it is sitting there, so it cannot shut itself down. Does anyone know
>how I might be able to force the thread to process messages? Or somehow
>force a return from the Read command? Any help would be appreciated.
>
>-George Kulz, Senior Software Engineer
> PowerSmart Inc.
>
>----------------------
>
>The views expressed here are mine and do not reflect the official position
>of my employer, or the organization through which the Internet was accessed.
>