创建一个Python类，在python宣布的情况下，与C API [英] Create instance of a python class , declared in python, with C API

问题描述

我想创建中定义的Python类的实例 __与C API主要__ 范围。

I want to create an instance of a Python class defined in the __main__ scope with the C API.

例如，该类称为 MyClass的键，定义如下：

For example, the class is called MyClass and is defined as follows:

class MyClass:
    def __init__(self):
        pass

类的类型住在 __ __主要范围。

在C应用程序，我想创建这个类的一个实例。这可能是简单地可能的 PyInstance_New ，因为它需要的类名。然而，这功能不可用在Python3。

Within the C application, I want to create an instance of this class. This could have been simply possible with PyInstance_New as it takes class name. However this function is not available in Python3.

任何帮助或建议的替代品是AP preciated。

Any help or suggestions for alternatives are appreciated.

谢谢，保罗

推荐答案

我相信最简单的方法是：

I believe the simplest approach is:

/* get sys.modules dict */
PyObject* sys_mod_dict = PyImport_GetModuleDict();
/* get the __main__ module object */
PyObject* main_mod = PyMapping_GetItemString(sys_mod_dict, "__main__");
/* call the class inside the __main__ module */
PyObject* instance = PyObject_CallMethod(main_mod, "MyClass", "");

当然，错误检查加。你只需要DECREF 实例当你用它做，另外两个是借来的引用。

plus of course error checking. You need only DECREF instance when you're done with it, the other two are borrowed references.

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