ctypes的 - 通过一个结构的指针另一个结构 [英] ctypes - passing a struct with a pointer to another struct

问题描述

在我的C code我有：

In my C code I have:

typedef struct{
    int info1;
    int info2;
    MoreData* md;
} BasicData;

typedef struct{
    int extinfo[100];
    char stuff[100];
} MoreData;

现在我有一个C库函数，它接受BasicData作为参数，我想从Python中调用它。
要做到这一点，我建立一个ctypes类：

Now I have a C library function which takes BasicData as argument and I want to call it from Python. To do this I construct a ctypes class:

class BasicData(Structure):
    _fields_ = [("info1", c_int),
                ("info2", c_int),
                ("md", ??????)]

我的问题是我该怎么补进????空间，能够通过这个结构为C函数（或者我需要完全不同的东西？）。 MOREDATA计算过程中只是用来和我不需要从它在我的Python $ C $阅读℃，它就会从C库级别处理，以便分配内存。我只需要通过使用正确的指针类型BasicData结构。

My question is what do I fill into ???? space to be able to pass this struct to C function (or do I need something completely different?). MoreData is just used during computations and I don't need to read from it in my Python code so allocating memory for it will be handled from C library level. I just need to pass a BasicData struct with correct pointer type.

推荐答案

如果您不需要分配或使用 MOREDATA 结构，那么 MD 只是一个普通的指针就ctypes的关注。使用无效* - 即 c_void_p

If you don't need to allocate or use the MoreData struct, then md is just a generic pointer as far as ctypes is concerned. Use a void * -- i.e. c_void_p.

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