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yoavhacohen

Joined: 20 Dec 2008
Posts: 2
Location: Israel

Posted: Thu Dec 25, 2008 12:03 pm Post subject: Array of arrays (float**)

Hi,

I have a native function that gets an array of pointers to arrays:

Code:

extern __declspect(dllexport) void foo(float**);

And I have a 2D managed array which I want to give the function as a parameter, *WITHOUT* copy its data.

I wrote this code, but sometimes I get an AccessViolationException when I call to the function (in other cases it works fine):

Code:

[DllImport(DLL_NAME)]
internal static extern void foo(IntPtr ptr);

public void FooWrapper(float[,] array)
{
int dim = array.GetLength(1);
int nRows = array.GetLength(0);

GCHandle _pinnedArray = GCHandle.Alloc(array, GCHandleType.Pinned);
unsafe
{
fixed (float* fixedFirstRow = &array[0,0])
{
float* rowPtr = (float*)(new IntPtr(fixedFirstRow).ToPointer());
// Allocate an array of float* pointers
int[] pointersToRows = new int[nRows];
for (int row = 0; row < nRows; ++row, rowPtr += dim)
{
pointersToRows[row] = new IntPtr(rowPtr).ToInt32;
}
GCHangle _rowPtrPinned = GCHandle.Alloc(pointersToRows, GCHanfleType.Pinned);
fixed (int* pointersToRowsHandle = &pointersToRows[0])
{
FooWrapper(new IntPtr(pointersToRowsHandle));
}
}
}

What am I doing wrong?
Is there a better way to do this?

Thanks in advance,
Yoav
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www.YoavHaCohen.com

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