python ctypes数组将无法正确返回

Question

This does not work:

def CopyExportVars(self, n_export):
    export_array = (ctypes.c_double * n_export)()
    self.dll_handle.vs_copy_export_vars(ctypes.cast(export_array,  ctypes.POINTER(ctypes.c_double)))
    return export_array().contents

I get this error ( n_export is 3):

TypeError: 'c_double_Array_3' object is not callable

Answer 1

Error is pretty self-explainatory. export_array is not a callable object, but you try to call it in last line of function. Also, you try to use pointer-related interface ('.contents') to retrieve value from array, not pointer to it.

Simplest way to make it work would be to convert ctypes result array to pure Python object and return it:

def CopyExportVars(self, n_export):
    export_array = (ctypes.c_double * n_export)()
    self.dll_handle.vs_copy_export_vars(ctypes.cast(export_array,  ctypes.POINTER(ctypes.c_double)))
    return list(export_array)