Question

我正在学习一下Sharma-C的延伸,并对为何必须用关键词来对待PyC的功能感到迷惑。

我对《常设机构》的理解是,它需要两点人来看待PyObjects,并将单一点人归为PyObject,例如。

 PyObject* myFunc(PyObject* self, PyObject* args)

如果我会利用一个使用关键词句的功能,那么这一功能将有三个点人去标语,并将一位点人带回一个PyObject——例如。

 PyObject* myFunc(PyObject* self, PyObject* args, PyObject* keywordArgs)

然而,当我设立单元功能阵列时(关于称为“添加器”的职能):

{ "adder", (PyCFunction)adder, METH_VARARGS | METH_KEYWORDS, "adder method" }

罚款。它感到,像我这样一片浮舟,现在仍然不得不使用浮体中的非排他性部分。如果我看不到这项工作的话,我会认为它不会奏效。我在这里不理解什么?

此外,我还看到有人提到“PyCFunctionWithKeywords”,这似乎有我认为需要的职能签字,但我的汇编者抱怨说(发出警告)存在不一致之处。

Was PyCFunctionWithKeywords deprecated? If not, is there a time when I should/must use it?

Answer 1

If your function handles keyword arguments, then it must correspond to a PyCFunctionWithKeywords. However, C doesn’t do overloading, and the structure built by PyMethodDef is defined to expect a PyCFunction, rather than, say, a completely unchecked void *. So you must cast your PyCFunctionWithKeywords to a PyCFunction to stop the compiler complaining, that’s all.

认为你还必须通过悬挂国旗的ESTH_KEYWORDS,以示你的职责是签署一份PyCFunctionWithKeywords,而不是一个PyC函数。

Answer 2

D Olveiro is 100% correct, but (depending on your compiler) you may still get a "cast-function-type" warning, which you can safely ignore. Or (if using a gcc varient) surround with pragma to temporarily turn off that warning:

#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wcast-function-type"
static PyMethodDef MyPythonMethods[] = {
    {"myMethod", (PyCFunction)MyMethodFunction, METH_VARARGS, "doc string"},
    ...
    {NULL, NULL, 0, NULL}
};
#pragma GCC diagnostic pop

友情链接