How to receive and return Windows data types in cython

[vinod kc]

Hi all,

I am writing a windows gui program in python. I am using ctypes to handle windows special data types and calling api functions. Recently I found that Cython will speedup certain areas of my program. So I am planning to move some work load of this program to a cython function where it takes windows data types like HDC, RECT etc and returns an HBRUSH. HDC & HBRUSH are void pointers. Ctypes will provide these types in python. But the problem is Cython can't return an HBRUSH from a function. How do I do it in Cython ? Thanks in advance.

[da-woods]

I'm slightly unclear what the exact problem is, but I guess your issue is returning these types to Python code, since Cython believes that functions returning pointers can only be used from Cython code.

If that's correct, I think you have two options:

1. Convert the handles to/from integers (by casting to uintptr_t before you return them). This isn't hugely type-safe since it lets you mix up different types of handle.

2. Create a cdef class that wraps each type of handle and return that.

On 06/01/2024 13:26, vinod kc wrote:

Hi all,

I am writing a windows gui program in python. I am using ctypes to handle windows special data types and calling api functions. Recently I found that Cython will speedup certain areas of my program. So I am planning to move some work load of this program to a cython function where it takes windows data types like HDC, RECT etc and returns an HBRUSH. HDC & HBRUSH are void pointers. Ctypes will provide these types in python. But the problem is Cython can't return an HBRUSH from a function. How do I do it in Cython ? Thanks in advance.

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[vinod kc]

@D Woods,

Thank you for the reply. You guessed it right. I want to return windows data types as well as I want to receive windows data types as function parameters. From your suggestions, I like the option 2. Even though I didn't know how to do it, but I hope I can find it out from the web.