Question

I have a function in C++ written as:

MyFunc(const double* pArray, int length);

I need to pass a non-constant array into it:

//C#
double[] myDoubleArray = new double[] { 1, 2, 3, 4, 5 };

MyFunc(myDoubleArray, 5);

The program is breaking when I do this.

edit:

//C# declaration

[DllImport(@"RTATMATHLIB.dll", EntryPoint = "?MyFunc@@YANPBNHHHH@Z")]
public static extern double MyFunc(double[] data, int length);

//C# usage
public static double MyFunc(double[] data)
{
    return MyFunc(data, data.Length);
}

//C++ export
__declspec(dllexport) double MyFunc(const double* data, int length);


//C++ signature
double MyFunc(const double* data, int length)
{
    return 0; //does not quite matter what it returns...
}

Answer 1

You can always pass a non-constant array to a function requiring a constant array. The const qualifier to the array implies that the function will not modify the contents of the array. The array does not need to be constant before passing to the function; the function will not modify the contents, due to the const in the declaration