SWIG C到Python的int数组 [英] SWIG C-to-Python Int Array

问题描述

我试图从Python的使用痛饮用以下原型访问C函数：

I am trying to access a C function with the following prototype from python using swig:

int cosetCoding(int writtenDataIn, int newData, const int memoryCells, int *cellFailure, int failedCell);

痛饮创建没有问题中的.so，我可以将其导入到蟒蛇，但是当我尝试用下面的访问它：

Swig creates the .so with no problems and I can import it into python, but when I try to access it with the following:

 cosetCoding.cosetCoding(10,11,8,[0,0,0,0,0,0,0,0],0)

我得到以下回溯：

I get the following traceback:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: in method 'cosetCoding', argument 4 of type 'int *'

指针应该是一个int数组的大小由memoryCells定义

The pointer is supposed to be an int array with size defined by memoryCells

推荐答案

如果你可以使用ctypes的。它更简单。不过，既然你问SWIG，你需要的是描述如何处理为int *类型映射一个。痛饮不知道有多少整数可能指向。下面是一个例子痛饮文档中砍死在<一个href=\"http://www.swig.org/Doc2.0/SWIGDocumentation.html#Typemaps_multi_argument_typemaps\">multi-argument typemaps ：

Use ctypes if you can. It is simpler. However, since you asked for SWIG, what you need is a typemap describing how to handle the int*. SWIG doesn't know how many integers may be pointed to. Below is hacked from an example in the SWIG documentation on multi-argument typemaps:

%typemap(in) (const int memoryCells, int *cellFailure) {
  int i;
  if (!PyList_Check($input)) {
    PyErr_SetString(PyExc_ValueError, "Expecting a list");
    return NULL;
  }
  $1 = PyList_Size($input);
  $2 = (int *) malloc(($1)*sizeof(int));
  for (i = 0; i < $1; i++) {
    PyObject *s = PyList_GetItem($input,i);
    if (!PyInt_Check(s)) {
        free($2);
        PyErr_SetString(PyExc_ValueError, "List items must be integers");
        return NULL;
    }
    $2[i] = PyInt_AsLong(s);
  }
}

%typemap(freearg) (const int memoryCells, int *cellFailure) {
   if ($2) free($2);
}

请注意，这个定义，从Python中调用时离开了 memoryCells 参数，只传递一个数组，如 [1,2,3 4] 为 cellFailure 。类型映射将生成 memoryCells 参数。

Note that with this definition, when called from Python leave out the memoryCells parameter and just pass an array such as [1,2,3,4] for cellFailure. The typemap will generate the memoryCells parameter.

P.S。我可以发布一个完全工作示例（适用于Windows），如果你想要它。

P.S. I can post a fully working example (for Windows) if you want it.

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