如何使用 SWIG 类型映射使用 P/Invoke 将结构成员从 C++ 编组到 C#?

问题描述

给定以下 SWIG 接口定义:

Given the following SWIG interface definition:

%module example

%include "arrays_csharp.i"
%apply int INOUT[] {int *x}

struct mystruct
{
        int *x;
}

SWIG 生成以下内容(来自 mystruct.cs 的片段):

SWIG produces the following (snippet from mystruct.cs):

  public int[] x {
    set {
      examplePINVOKE.mystruct_x_set(swigCPtr, value);
    }
    get {
      IntPtr cPtr = examplePINVOKE.mystruct_x_get(swigCPtr); // Error 1
      SWIGTYPE_p_int ret = (cPtr == IntPtr.Zero) ? null : new SWIGTYPE_p_int(cPtr, false);
      return ret; //Error 2
    }
  }

这会导致 VS2010 产生以下两个错误:

This causes VS2010 to produce the following two errors:

Error   1   Cannot implicitly convert type 'int[]' to 'System.IntPtr'
Error   2   Cannot implicitly convert type 'LibLinear.SWIG.SWIGTYPE_p_int' to 'int[]'

在上面代码片段中标记的区域.

at the areas marked in the above code snippet.

我根据http://www.swig.org/开发了界面Doc1.3/CSharp.html#CSharp_arrays_pinvoke_default_array_marshalling ，只讨论函数而不讨论结构.结构成员的接口定义应该不同吗?

I developed the interface according to http://www.swig.org/Doc1.3/CSharp.html#CSharp_arrays_pinvoke_default_array_marshalling , which only talks about functions but not structures. Should the interface definition for structure members be different?

推荐答案

可能是因为内存中的大小/布局未知(这对 int/double/等等...).您可以使用结构向量代替吗?通过简单地包含 std_vector.i 和相关的类型映射，我在传递结构向量或自定义对象方面没有问题，例如:

It might be that it can't handle an array of structs because of the unknown size/layout in memory (which is not a problem for int/double/etc...). Is it possible for you to use a vector of structs instead? I've had no problems passing vectors of structs or custom objects by simply including std_vector.i and relevant typemaps, eg:

%include "std_vector.i"

%typemap(MyClassVec) std::vector<MyClass>;

这篇关于如何使用 SWIG 类型映射使用 P/Invoke 将结构成员从 C++ 编组到 C#?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！