variants and freeing bstr memory (C++)
 

I am having a problem with Excel 2003 running out of "memory
handles" on my Windows 7 x64 box after creating several hundred
excel spreadsheets. I am explicitly releasing all of my Dispatch
pointers. Do I need to explicitly release my variants after I
store a bstr in them ? For instance, the following code converts
a cell range string into a bstr and gets excel to return a Dispatch
pointer for putting stuff into that range.

VARIANT range;
VariantInit ( & range);
range.vt = VT_BSTR;
_bstr_t address = _bstr_t (cellAddress.c_str ());
range.bstrVal = address;
std::string errorMsg = "Select a range in the active spreadsheet, " + cellAddress +
" (PutStringInServer)";
OLEMethod (DISPATCH_PROPERTYGET, & result1, pExcelSheet, L"Range", errorMsg, 1, range);
if (result1.vt == VT_DISPATCH)
{
....

So, do I need to release the range variant variable ?

Thanks,
Lynn

variants and freeing bstr memory (C++)
 

On 11/30/2010 2:40 PM, Lynn McGuire wrote:
I am having a problem with Excel 2003 running out of "memory
handles" on my Windows 7 x64 box after creating several hundred
excel spreadsheets. I am explicitly releasing all of my Dispatch
pointers. Do I need to explicitly release my variants after I
store a bstr in them ? For instance, the following code converts
a cell range string into a bstr and gets excel to return a Dispatch
pointer for putting stuff into that range.

VARIANT range;
VariantInit ( & range);
range.vt = VT_BSTR;
_bstr_t address = _bstr_t (cellAddress.c_str ());
range.bstrVal = address;
std::string errorMsg = "Select a range in the active spreadsheet, " + cellAddress +
" (PutStringInServer)";
OLEMethod (DISPATCH_PROPERTYGET, & result1, pExcelSheet, L"Range", errorMsg, 1, range);
if (result1.vt == VT_DISPATCH)
{
...

So, do I need to release the range variant variable ?

Thanks,
Lynn

I've been looking at VariantClear
http://msdn.microsoft.com/en-us/library/ms221165.aspx
and it appears that VariantClear should always be called for
any variant containing a dispatch pointer or a bstr pointer.

Lynn

variants and freeing bstr memory (C++)
 

On 11/30/2010 5:42 PM, Lynn McGuire wrote:
On 11/30/2010 2:40 PM, Lynn McGuire wrote:
I am having a problem with Excel 2003 running out of "memory
handles" on my Windows 7 x64 box after creating several hundred
excel spreadsheets. I am explicitly releasing all of my Dispatch
pointers. Do I need to explicitly release my variants after I
store a bstr in them ? For instance, the following code converts
a cell range string into a bstr and gets excel to return a Dispatch
pointer for putting stuff into that range.

VARIANT range;
VariantInit ( & range);
range.vt = VT_BSTR;
_bstr_t address = _bstr_t (cellAddress.c_str ());
range.bstrVal = address;
std::string errorMsg = "Select a range in the active spreadsheet, " + cellAddress +
" (PutStringInServer)";
OLEMethod (DISPATCH_PROPERTYGET, & result1, pExcelSheet, L"Range", errorMsg, 1, range);
if (result1.vt == VT_DISPATCH)
{
...

So, do I need to release the range variant variable ?

Thanks,
Lynn

I've been looking at VariantClear
http://msdn.microsoft.com/en-us/library/ms221165.aspx
and it appears that VariantClear should always be called for
any variant containing a dispatch pointer or a bstr pointer.

OK, I now know that you cannot VariantClear any variant that
you have added to a SafeArray using SafeArrayPutElement.
I thought that SafeArrayPutElement does a deep copy on the
variant containing a BStr being added to SafeArray but I was
wrong. That is a sure way to lose your string headed to Excel.

Lynn