我写周围写在C ++ \ CLI的托管组件的本机包装。

我在管理code以下功能：

 阵列和LT;字节＆GT; ^类::函数（）;
 

我想从一个本地C暴露该功能++类具有以下签名：

  shared_array＆LT; unsigned char型＆GT;类::函数（）;
 

我已经得到了尽可能调用从本地code中的管理功能，但我不知道如何安全地复制管理的阵列到非托管的。

  gcroot＆LT; CLI ::数组＆lt;系统::字节＆GT; ^＆GT; managedArray = _managedObject-＆GT;功能（）;
 

解决方案

有两种常用的方法：

执行与本机code，这需要使用的 pin_ptr＆LT;＆GT; ：

 的boost :: shared_array＆LT; unsigned char型＆GT;转换（阵列＆LT; unsigned char型＆GT; ^ ARR）
{
    提高:: shared_array＆LT; unsigned char型＆GT; DEST（新的无符号的char [arr-＆GT;长度]）;
    pin_ptr＆LT; unsigned char型＆GT;钉扎=安培;常用3 [0];
    无符号字符* SRC =固定;
    性病::复制（SRC，SRC + arr-＆GT;长度，dest.get（））;
    返回DEST;
}
 

执行与管理code，这就要求使用的元帅类：

 的boost :: shared_array＆LT; unsigned char型＆GT;转换（阵列＆LT; unsigned char型＆GT; ^ ARR）
{
    使用系统：运行时:: InteropServices ::元帅;

    提高:: shared_array＆LT; unsigned char型＆GT; DEST（新的无符号的char [arr-＆GT;长度]）;
    元帅::复制（ARR，0，IntPtr的（dest.get（）），arr-＆GT;长度）;
    返回DEST;
}
 

一般来说，我会preFER后一种方式，因为前者会阻碍GC的有效性，如果数组是很大的。

I'm writing a native wrapper around a managed component written in C++\CLI.

I have the following function in managed code:

array<Byte>^ Class::Function();

I want to expose this function from a native C++ class with the following signature:

shared_array<unsigned char> Class::Function();

I've gotten as far as calling the managed function from native code, but I'm not sure how to safely copy the managed array into an unmanaged one.

gcroot<cli::array<System::Byte>^> managedArray = _managedObject->Function();

There are two usual approaches:

Perform the marshaling with native code, which requires use of pin_ptr<>:

boost::shared_array<unsigned char> convert(array<unsigned char>^ arr)
{
    boost::shared_array<unsigned char> dest(new unsigned char[arr->Length]);
    pin_ptr<unsigned char> pinned = &arr[0];
    unsigned char* src = pinned;
    std::copy(src, src + arr->Length, dest.get());
    return dest;
}

Perform the marshaling with managed code, which requires use of the Marshal class:

boost::shared_array<unsigned char> convert(array<unsigned char>^ arr)
{
    using System::Runtime::InteropServices::Marshal;

    boost::shared_array<unsigned char> dest(new unsigned char[arr->Length]);
    Marshal::Copy(arr, 0, IntPtr(dest.get()), arr->Length);
    return dest;
}

Generally I would prefer the latter approach, as the former can hinder the GC's effectiveness if the array is large.