cimport results in struct declaration being copied into another location

[Colin Pattison]

Hey Guys - 

I’ve just started using Cython after having handwritten extensions for a while. I’ve run into an issue and would appreciate any insight you guys have - I have a common pxd which wraps our standard data representation. I then have module B built separately that cimports the data representation. This then results in a redefinition error as the struct DataPy appears in the header for the common module and then is redefined in the cpp of module B. Is there any way around this?

A replication of this is attached - build the common module first using the setup.sh, then build the session module using the setup.sh. DataPy will be declared in common.h and then redeclared in session.cpp.

Is there any way to avoid this happening?

Cheers

C

[Robert Bradshaw]

The problem is that you're using "include."

Just define your Data class in common.pxd/common.pyx, and cimport them
from everywhere else.

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[Colin Pattison]

Thanks Rob - the problem is I needed to get access to the function from a pure C++ class to convert the C++ data representation into a Python one. 

I got around the issue by returning a PyObject* rather than my extension type which meant it wasn't duplicated into the header. At this point however I was not correctly using the "public api" declaration, I suspect if I had declared the function properly as an api one and included the _api.h file this would have been fine

C