public static void UseCasePassPointer()
{
long[] inputArray = new long[] { 2, 4, 6, 8, 10, 12 };
long[] outputArray = new long[inputArray.Length];
int batchSize = inputArray.Length;
// copy to unmanaged memory to call unmanaged function
GCHandle handle = GCHandle.Alloc(inputArray, GCHandleType.Pinned);
IntPtr inputBatch = handle.AddrOfPinnedObject();
// allocate memory in unmanaged heap for result
IntPtr resultBatch = Marshal.AllocHGlobal(sizeof(long) * batchSize);
// call the unmanaged function
InteropFunc.CalcFactorialInBatch(inputBatch, resultBatch, batchSize);
// copy result to managed memory
Marshal.Copy(resultBatch, outputArray, 0, batchSize);
// free allocated memory from unmanaged heap
// note that a production app should consider catching
// exceptions and freeing allocated unmanaged memory
handle.Free();
Marshal.FreeHGlobal(resultBatch);
for (int i = 0; i < batchSize; ++i)
{
Console.WriteLine("Batch factorial of {0} is {1}", inputArray [i], outputArray [i]);
}
}
public static void UseCaseSimplest()
{
for (int i = 1; i < 10; ++i)
{
Console.WriteLine("Factorial of {0} is {1}", i, InteropFunc.CalcFactorial(i));
}
}