Question

我正在尝试使用SWIG在C和Python之间传递结构。我是Python和C的新手。我搜索了passing structure using SWIG，没有成功。

我的代码来自SWIG Python tutorial，第55页和第56页的示例。它应该从Python获取输入值，在C中将它们乘以2并将结果返回给Python。我收到错误AttributeError: 'module' object has no attribute 'new_info。

sample.c文件

#include <stdio.h>
#include "sample.h"

struct info sample;

void getstruct (struct info *sample);

void getstruct (struct info *sample) {

   int i = 0;
   int j = 0;
   int k = 0;
   int l = 0;

   i = 2 * sample->i;
   j = 2 * sample->j;
   k = 2 * sample->k;
   l = 2 * sample->l;

   sample->i = i;
   sample->j = j;
   sample->k = k;
   sample->l = l;

   return(&sample);

}

sample.i

%module sample
%{
typedef struct
{
   int i;
   int j;
   int k;
   int l;
} info;

extern void getstruct (struct info *sample);

info *new_info(int i, int j, int k, int l) {
    info *in = (info *) malloc(sizeof(info));
    in->i = i;
    in->j = j;
    in->k = k;
    in->l = l;
    return in;
}

void delete_info(info *in) {
    free(in);
}
%}

extern void getstruct (struct info *sample);
typedef struct
{
   int i;
   int j;
   int k;
   int l;
} info;

执行构建包装器的命令：

swig -python sample.i
gcc -fPIC -c sample.c sample_wrap.c -I/usr/include/python2.7
ld -shared sample.o sample_wrap.o -o _sample.so

Python错误：

[GCC 4.8.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import sample
>>>
>>> print sample
<module 'sample' from 'sample.pyc'>
>>> print sample.getstruct(1,2,3,4)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: getstruct() takes exactly 1 argument (4 given)
>>> v = new_info(1,2,3,4)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'new_info' is not defined
>>> v = sample.new_info(1,2,3,4)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'module' object has no attribute 'new_info'
>>>

Answer 1

在sample.i文件中，您已通过在new_info和{{1}内声明，将delete_info和%{函数直接添加到包装器代码中但是没有告诉SWIG为这些函数生成包装器。在%} / %{之外再次重复代码，或使用%} / %inline %{。后者将代码直接添加到包装器中，并告诉SWIG将其包装起来。

使用SWIG在Python和C之间传递结构

1 个答案: