On 2013-01-21 16:52, Steve Simmons wrote:
Mike,
Thanks for your response - I was puzzled by one part of it though...
On 21/01/2013 15:14, Mike C. Fletcher wrote:
That's because you've just discarded the object you created
I (mis?)understood from the ctypes documentation that '>>> initResult =
c_short(0)' would result in the creation of a ctypes 'short' called
initResult and that this object would be mutable. On that basis, I
expected the following statement '>>> initResult = initScanLib( ... )'
would assign the result of the call to initResult.
So, I can understand that I am not using the correct approach but I
don't understand how I discarded the object I created. Can you clarify
please?
This:
initResult = initScanLib( ... )
will make initResult refer to whatever initScanLib(...) returned, just
as this:
initResult = c_short(0)
will make initResult refer to whatever c_short(0) returned.
What you were doing was this:
1. You created a c_short object and bound initResult to it.
2. You called a function and bound initResult to its result, unbinding
the c_short object in the process.
3. There were no other references to the c_short object, therefore it
could be discarded by the garbage collector.
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