从C#中不受管理的C DLL获取字节数组上的指针

在C我有这样的功能

extern "C" _declspec(dllexport) uint8* bufferOperations(uint8* incoming, int size)

我正在尝试像这样从c#调用它

[DllImport("MagicLib.DLL", CallingConvention = CallingConvention.Cdecl)]
//[return: MarshalAs(UnmanagedType.ByValArray)]//, ArraySubType=UnmanagedType.SysUInt)]
public static extern byte[] bufferOperations(byte[] incoming, int size);

但是我得到了
无法封送“返回值”：无效的托管/非托管类型组合

(((问题是-如何正确编组？
感谢您阅读我的问题

解决方法:

byte []是长度已知的.Net数组类型.您无法将字节*封送给它,因为.Net不知道输出数组的长度.您应该尝试手动编组.用byte *替换byte [].然后,这样做：

[DllImport("MagicLib.DLL", CallingConvention = CallingConvention.Cdecl)]
public static extern byte* bufferOperations(byte* incoming, int size);

public void TestMethod()
{
    var incoming = new byte[100];
    fixed (byte* inBuf = incoming)
    {
        byte* outBuf = bufferOperations(inBuf, incoming.Length);
        // Assume, that the same buffer is returned, only with data changed.
        // Or by any other means, get the real lenght of output buffer (e.g. from library docs, etc).
        for (int i = 0; i < incoming.Length; i++)
            incoming[i] = outBuf[i];
    }
}

标签：c,dll,unmanaged,marshalling,c-2
来源： https://codeday.me/bug/20191012/1897223.html