# c++ c#结构体调用

> 来源：梦飞idc云平台 | 原文：https://www.mfisp.com/21890.html | 发布：2023-07-07 | 更新：2023-07-07 | 分类：建站教程

**1、最近做项目遇到，C#调用C++dll里的函数需要传递结构体参数，发现这个并不是简单的在C#里定义相应的结构体就可以的，下面以一个例子来说明解决的办法，C++中的函数和结构体如下：**

 

uint msec_set_igr_gen_cfg(int port, IGR_GEN_T *igr_gen)  
{

 

return 0;  
}

 

typedef struct {  
 int aa_disable; /*/< authentiation adjust checking disable */  
 int badtag_rej; /*/< reject packet if it is bypassed due to badtag */  
 int pad_en; /*/< pad non-rejected packets up to 64B */  
 int byp_ctl_sl; /*/< bypass packet if SL field does not correspond to packet len */  
 int byp_ctl_v; /*/< bypass packet if V bit is set */  
 int byp_ctl_sc; /*/< bypass packet if SC bit and either ES or SCB bits are set */  
 int byp_ctl_ec; /*/< bypass packet if DC bits are not 00 or 11 */  
 int sectag_flag; /*/< select which flag bit indicates that a SEC tag was present in pkt */  
} IGR_GEN_T;

 

在C#中 首先需要使用Dllimport将相应的C++dll load进来，然后定义相应的结构体，具体如下：

 

[DllImport("..\\debug\\mgd_MacSec.dll")]  
 private static extern UInt32 msec_set_igr_gen_cfg(int port, IntPtr igr_gen);

  

结构体定义：

 

[StructLayout(LayoutKind.Sequential)]  
 public class IGR_GEN_T   
 {  
 int aa_disable; /*/< authentiation adjust checking disable */  
 int badtag_rej; /*/< reject packet if it is bypassed due to badtag */  
 int pad_en; /*/< pad non-rejected packets up to 64B */  
 int byp_ctl_sl; /*/< bypass packet if SL field does not correspond to packet len */  
 int byp_ctl_v; /*/< bypass packet if V bit is set */  
 int byp_ctl_sc; /*/< bypass packet if SC bit and either ES or SCB bits are set */  
 int byp_ctl_ec; /*/< bypass packet if DC bits are not 00 or 11 */  
 int sectag_flag; /*/< select which flag bit indicates that a SEC tag was present in pkt */  
 public IGR_GEN_T()  
 {  
 aa_disable = 0;  
 badtag_rej = 0;  
 pad_en = 0;  
 byp_ctl_ec = 0;  
 byp_ctl_sc = 0;  
 byp_ctl_sl = 0;  
 byp_ctl_v = 0;  
 sectag_flag = 0;  
 }  
 } ;

 

在代码中具体引用函数时如下所示，

 

IntPtr ptr = Marshal.AllocHGlobal(Marshal.SizeOf(igr_gen));  
 Marshal.StructureToPtr(igr_gen, ptr, false);  
 UInt32 ret = _msec_set_igr_gen_cfg(port, ptr);  
 igr_gen = (IGR_GEN_T)Marshal.PtrToStructure(ptr, typeof(IGR_GEN_T));  
 Marshal.FreeHGlobal(ptr);  
 return ret;

 

从以上步骤可以看出，结构体参数的传递需要marshal做辅助做相应的转化，以intptr的方式传输结构体参数。

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