Re: Multi Threading Issue

I have an MFC app developed in VS2005 that uses a thread to receive data from
external devices (using serial comm api). These devices may be connected via
straight serial or usb which is then converted to serial for my app.
 
The reader thread uses WaitCommEvent to wait for a char to be placed in the
receive buffer, then it processes the data in that buffer. This thread
reports back to the app data received from the device connected to the port.
This is usually acknowledges sent by the device in response to data sent from
the app.

The app also uses another thread to "ping" the device, using the same
connection, at fixed intervals (2 secs). The device sends acks back to the
app when the "ping" is received.

The problem I am encountering is that the reader thread is not reading the
data in the port buffer until the ping thread sends a "ping" out the port.

I've played with thread priority to see if that made a difference - but it
doesn't.
Any idea why these threads seem to be interlocked?