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CComSafeArray Class 

This class is a wrapper for the SAFEARRAY structure.


template <
   typename T,
   VARTYPE _vartype = _ATL_AutomationType< T >::type
>
class CComSafeArray

Parameters

T

The type of data to be stored in the array.

CComSafeArray provides a wrapper for the SAFEARRAY Data Type class, making it a simple matter to create and manage single- and multidimensional arrays of almost any of the VARIANT-supported types.

CComSafeArray simplifies passing arrays between processes, and in addition provides extra security by checking array index values against upper and lower bounds.

The lower bound of a CComSafeArray can start at any user-defined value; however, arrays that are accessed through C++ should use a lower bound of 0. Other languages such as Visual Basic may use other bounding values (for example, -10 to 10).

Use CComSafeArray::Create to create a CComSafeArray object, and CComSafeArray::Destroy to delete it.

A CComSafeArray can contain the following subset of VARIANT data types:

VARTYPE Description

VT_I1

char

VT_I2

short

VT_I4

int

VT_I4

long

VT_I8

longlong

VT_UI1

byte

VT_UI2

ushort

VT_UI4

uint

VT_UI4

ulong

VT_UI8

ulonglong

VT_R4

float

VT_R8

double

VT_DECIMAL

decimal pointer

VT_VARIANT

variant pointer

VT_CY

Currency data type

Header: atlsafe.h

// Create a multidimensional array, 
// then write and read elements

#include "stdafx.h"
#include "atlsafe.h"

int main(int argc, char* argv[])
{
   // Define an array of character pointers
   CComSafeArray<char> *pSar;

   char cElement;
   char cTable[2][3] = {'A','B','C','D','E','F'};

   // Declare the variable used to store the
   // array indexes
   LONG aIndex[2];

   // Define the array bound structure
   CComSafeArrayBound bound[2];
   bound[0].SetCount(3);
   bound[0].SetLowerBound(0);
   bound[1].SetCount(3);
   bound[1].SetLowerBound(0);   
   
   // Create a new 2 dimensional array
   // each dimension size is 3
   pSar = new CComSafeArray<char>(bound,2); 

   // Use MultiDimSetAt to store characters in the array
   for (int x = 0; x < 2; x++)
   {
      for (int y = 0; y < 3; y++)
      {
         aIndex[0] = x;
         aIndex[1] = y;
         HRESULT hr = pSar->MultiDimSetAt(aIndex,cTable[x][y]);
         ATLASSERT(hr == S_OK);
      }
   }
   // Use MultiDimGetAt to retrieve characters in the array
   for (int x = 0; x < 2; x++)
   {
      for (int y = 0; y < 3; y++)
      {
         aIndex[0]=x;
         aIndex[1]=y;
         HRESULT hr = pSar->MultiDimGetAt(aIndex,cElement);
         ATLASSERT(hr == S_OK);
         ATLASSERT(cElement == cTable[x][y]);
      }   
   }
   return 0;
}

Only the following VARTYPEs are fully supported: VT_BSTR, VT_VARIANT, VT_UNKNOWN, and VT_DISPATCH.

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