Getting data from ctypes array into numpy

Question

I am using a Python (via ctypes) wrapped C library to run a series of computation. At different stages of the running, I want to get data into Python, and spec

Answer 1

If you are ok with creating arrays in python, the following example with 2d array works in python3:

import numpy as np
import ctypes

OutType = (ctypes.c_float * 4) * 6
out = OutType()
YourCfunction = ctypes.CDLL('./yourlib.so').voidreturningfunctionwithweirdname
YourCfunction.argtypes = [ctypes.POINTER(ctypes.c_float)]*3, ctypes.POINTER(ctypes.c_float)]*5, OutType]
YourCfunction(input1, input2, out)
out = np.array(out) # convert it to numpy

print(out)

numpy and ctypes versions are 1.11.1 and 1.1.0