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To retrieve the identical object through pass by reference when invoking C++ code from Python using ctypes, you can use the ctypes.pointer() function to create a pointer to the object in memory. Then, you can pass this pointer as a parameter to the C++ function.

For example, suppose you have a C++ function called "modifyObject" that takes a pointer to an object and modifies it in place:

void modifyObject(MyObject* obj) {
    obj->someProperty = 42;
}

To call this function from Python using ctypes and retrieve the same object instance, you can do the following:

import ctypes

class MyObject(ctypes.Structure):
    _fields_ = [('someProperty', ctypes.c_int)]

# Create an instance of the object
obj = MyObject()

# Call the C++ function with a pointer to the object
ctypes.cdll.mylibrary.modifyObject(ctypes.pointer(obj))

# The object has been modified in place
print(obj.someProperty)  # Outputs 42