Threading tips.

[Gordon McMillan]

Arinté wrote: 

>Its me again with questions about my embedded python app.  My scripts
>are primarily to talk to devices.  

I read this as saying App calls Python reads device.

>If a script is running and the device
>does something, then I want the app to call the py script callback if
>one was set.  

I read this as saying Python calls extension-that-read-devices calls back 
into Python.

>Do I need to block the Python threads?  What other steps
>do I need to take?

If that's an extension reading the device, it needs to 
Py_BEGIN_ALLOW_THREADS and Py_END_ALLOW_THREADS so it doesn't block Python 
while waiting on the device. If the callback is made on the same thread 
that sent the extension off to read the device, everything should be fine.

If, however, you extension has created it's own thread, you need to create 
a valid Python thread object for that new thread before it can call back 
into Python. That is very advanced stuff.

- Gordon