Question

我在使用Marsolling C DLL结构时遇到麻烦这是C DLL中的代码

// cbool.h

#ifndef CBOOL_H
#define CBOOL_H

#define false         0
#define true          !false
typedef unsigned char boolean; /* false=0, otherwise true */

#endif


// test.h
#include "cbool.h"

typedef struct
{
    bool a;
    bool b;
  float c;

} BoolStruct;

extern BoolStruct BStruct;
__declspec(dllexport) void  GetBStruct  (BoolStruct* bs);
__declspec(dllexport) void  SetBStruct  (BoolStruct* bs);

// test.c
#include "test.h"

BoolStruct BStruct;
void    GetBStruct  (BoolStruct* bs)
{
*bs = BStruct;
}

void    SetBStruct  (BoolStruct* bs)
{
BStruct = *bs; 
}

和C＃

public struct BoolStruct
{
    public bool a;
    public bool b;
  public float c;

}

BoolStruct bs;

[DllImport(DLL_NAME, EntryPoint = "GetBStruct")]
public static extern void GetBStruct(ref BoolStruct bs);

[DllImport(DLL_NAME, EntryPoint = "SetBStruct")]
public static extern void SetBStruct(ref BoolStruct bs);


bs.a = true;
bs.c = 0.5F;

... set
...get

但是使用float类型设置并且获取值是正确的，而当我设置boll（例如true）时，我总是收到错误你能救我吗？

Answer 1

我尝试了您的代码和建议，但不能工作...... 我通过编辑文件CBool暂时解决了

typedef int boolean; /* false=0, otherwise true */

它有效！在另一个类似的情况下

typedef struct {

    // don't work!
    //char TestString[5];

    // work!
    int TestString[5];

} MyStruct;

和C＃

[StructLayout(LayoutKind.Sequential, CharSet=CharSet.Ansi)]
public struct MyStruct
{
  public MyStruct(uint i)
  {
     // ......
    TestString = new char[5];
  }

  [MarshalAs(UnmanagedType.ByValArray, SizeConst=5)]
  public char[] TestString;  

}

似乎char和unsigned是问题，或者我做错了什么，否则，但不知道是什么

Answer 2

尝试：

[StructLayout(LayoutKind.Sequential)]
public struct BoolStruct
{
    [MarshalAs(UnmanagedType.U1)]
    public bool a;

    [MarshalAs(UnmanagedType.U1)]
    public bool b;

    public float c;
}

By default the bool is marshaled as an Int32 in .NET.

您应该在执行PInvoke时指定StructLayout（但请注意struct it isn't necessary：要减少与自动值相关的布局相关问题，请执行C＃，Visual Basic和C ++编译器为值类型指定顺序布局。）

啊，你忘记了CallingConvention：对于C函数通常是Cdecl：

[DllImport("CPlusPlusSide.dll", EntryPoint = "GetBStruct", CallingConvention = CallingConvention.Cdecl)]
public static extern void GetBStruct(ref BoolStruct bs);

[DllImport("CPlusPlusSide.dll", EntryPoint = "SetBStruct", CallingConvention = CallingConvention.Cdecl)]
public static extern void SetBStruct(ref BoolStruct bs);

（测试x86和x64）

C＃Marshaling C DLL struct bool

2 个答案: