Re: Function References

squishywaffle@xxxxxxxxx wrote:
Greetings,

I'm trying to wrap a function in a C library as a compiled C Python
module. Everything is going great, but I've hit a snag. There's a
function in the form of this:

First the typedef:
typedef void(*FPtr_DeviceMessageHandler) (const DeviceMessage, const
char*);

Then the actual function prototype:
FPtr_DeviceMessageHandler
RegisterDeviceMessageHandler(FPtr_DeviceMessageHandler);
[...]
[I] can't figure out how to cast the function reference from Python into
something the C RegisterDevice... function can handle.

Mere casting won't do the trick. The function reference from Python is basically just an object that contains byte-code to be executed by the Python Virtual Machine. There is no way you can magically transform that into a C function by casting the Python object pointer to anything.

You'll need a write a C function that will call a given Python function, and then you need to supply the pointer to that C function as your DeviceMessageHandler callback function, and somehow communicate to your C function which Python function it should call.

Good luck.

--
Carsten Haese
http://informixdb.sourceforge.net
.

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