从 Intptr 到 Double[] 执行 marshal.copy 时出现访问冲突错误

Question

这不是实际代码。但我想在我的实际代码中做类似的事情。即将从 C# 获取双指针，并将 vaules 填充到 cpp 代码中，并将 marshal.copy 从 IntPtr 到 double [] 到 C# 代码中。这就是我尝试过的。但它会导致访问冲突。

C++代码：

__declspec(dllexport) void FillDoubleValues(IN UInt64 _NumSamplesToCapture, OUT double* pSamples)
{
    for (int i = 0; i < _NumSamplesToCapture; i++)
    {
        pSamples[i] = (double)rand() / RAND_MAX;
    }
}

C#:

[DllImport("LibOperation.dll", CallingConvention = CallingConvention.Cdecl)]
static public extern voi FillDoubleValues( [IN] UInt64 _NumSamplesToCapture, out IntPtr pSamples);
   

void main(){

UInt64 NumSamplesToCapture = 5000;

Intptr Sample;

FillDoubleValues(NumSamplesToCapture, out Sample);

double[] ys1 = new double[NumSamplesToCapture];

Marshal.Copy(Samples, ys1, 0, ys1.Length);

// ys1 wil be used to plot values

}

Marshal.Copy 给出错误 "System.AccessViolationException: 'Attempted to read or write protected memory. This is often indication that other memory is corrupt."

我在这里犯的任何错误。

提前致谢。

Answer 1

只需使用常规数组编组，无需自己编组

[DllImport("LibOperation.dll", CallingConvention = CallingConvention.Cdecl)]
static public extern void FillDoubleValues(UInt64 _NumSamplesToCapture, [Out, MarshalAs(UnmanagedType.LPArray, SizeParamIndex = 0)] double[] pSamples);
   

void main()
{
    UInt64 NumSamplesToCapture = 5000;
    double[] ys1 = new double[NumSamplesToCapture];
    FillDoubleValues(NumSamplesToCapture, ys1);
}

从 Intptr 到 Double[] 执行 marshal.copy 时出现访问冲突错误

Access Violation Error while doing marshal.copy from Intptr to Double[]

c#

pinvoke