如何从C访问Python全局变量？

I have some global variables in a Python script. Some functions in that script call into C - is it possible to set one of those variables while in C and if so, how?

我在Python脚本中有一些全局变量。该脚本中的某些函数调用C - 是否可以在C中设置其中一个变量，如果是，如何？

I appreciate that this isn't a very nice design in the first place, but I need to make a small change to existing code, I don't want to embark on major refactoring of existing scripts.

我很欣赏这首先不是一个非常好的设计，但是我需要对现有代码进行一些小改动，我不想对现有脚本进行重大的重构。

4 个解决方案

#1

I'm not a python guru, but I found this question interesting so I googled around. This was the first hit on "python embedding API" - does it help?

我不是一个蟒蛇大师，但我发现这个问题很有趣所以我google了一下。这是“python嵌入API”的第一个热门 - 它有帮助吗？

If the attributes belong to the global scope of a module, then you can use "PyImport_AddModule" to get a handle to the module object. For example, if you wanted to get the value of an integer in the main module named "foobar", you would do the following:

如果属性属于模块的全局范围，则可以使用“PyImport_AddModule”来获取模块对象的句柄。例如，如果要在名为“foobar”的主模块中获取整数的值，则执行以下操作：
PyObject *m = PyImport_AddModule("__main__");
PyObject *v = PyObject_GetAttrString(m,"foobar");

int foobar = PyInt_AsLong(v);

Py_DECREF(v);

#2

For anyone coming here from Google, here's the direct method:

对于来自谷歌的任何人来说，这是直接的方法：

PyObject* PyEval_GetGlobals()

https://docs.python.org/2/c-api/reflection.html

https://docs.python.org/3/c-api/reflection.html

The return value is accessed as a dictionary.

返回值作为字典访问。

#3

I recommend using pyrex to make an extension module you can store the values in in python, and cdef a bunch of functions which can be called from C to return the values there.

我建议使用pyrex创建一个扩展模块，你可以将值存储在python中，并cdef一堆函数，可以从C调用它们返回值。

Otherwise, much depends on the type of values you're trying to transmit.

否则，很大程度上取决于您尝试传输的值的类型。

#4

Are you willing to modify the API a little bit?

您是否愿意稍微修改API？

You can make the C function return the new value for the global, and then call it like this:

你可以让C函数返回全局的新值，然后像这样调用它：

my_global = my_c_func(...)

my_global = my_c_func（...）
If you're using Robin or the Python C API directly, you can pass the globals dictionary as an additional parameter and modify it

如果您直接使用Robin或Python C API，则可以将全局字典作为附加参数传递并进行修改
If your global is always in the same module, Sherm's solution looks great
如果您的全局总是在同一个模块中，那么Sherm的解决方案看起来很棒

#1