Using CString into static method

[mesajflaviu]

I am stuck into a strange problem. I have MDI app, which has a struct into CDocument:

class CMyDoc : public CDocument
{
...

struct SRecord
{
    SRecord(){}
    virtual ~SRecord(){}
    CString sName;
    CString sState;
    CString sDateu;
    CString sDatec;
};

CTypedPtrArray<CPtrArray, SRecord*> m_arrRecord;

and somewhere in document I load this struct with data:

    SRecord* pItem = new SRecord;
    pItem->sName        = saItem.GetAt(ML_ASSETNAME);
    pItem->sState       = saItem.GetAt(ML_STATE);
    pItem->sDateu       = saItem.GetAt(ML_DATEU;
    pItem->sDatec       = saItem.GetAt(ML_DATEC);
    m_arrRecord.Add(pItem);

ok by now. I am trying to sort data:

void CMyDoc::SortData(int nColumn, BOOL bAscending)
{
switch(nColumn)
{
case 9:
    if(bAscending)qsort((void*)m_arrRecord.GetData(), m_arrRecord.GetSize(), sizeof(SRecord), CompareDateUAscending);
    else qsort((void*)m_arrRecord.GetData(), m_arrRecord.GetSize(), sizeof(SRecord), CompareDateUDescending);
    break;
...
}

but the problem occur when data is access in static method:

//static method:
int CMyDoc::CompareDateUDescending(const void* arg1, const void* arg2)
{
SRecord* Record1 = *(SRecord**)arg1;    // <-- OK
SRecord* Record2 = *(SRecord**)arg2;    // <-- Unhandled exception* see note below

if(Record1->sDateu.IsEmpty() || Record2->sDateu.IsEmpty())
    return 0;

COleDateTime dL, dR;
dL.ParseDateTime(Record1->sDateu);
dR.ParseDateTime(Record2->sDateu);

return (dL == dR ? 0 : (dL < dR ? 1 : -1));
}

*and the crash told me:
"An unhandled exception was encountered during a user callback."

What could be the problem ? Can you help me ? Thank you.

[2kaud]

What is the value of arg2 when it is attempted to be dereferenced - and is it valid? If you single step through this code with the debugger what happens?

What is the type of m_arrRecord.GetData() ?

Assuming .GetData() returns a pointer to an array of SRecord, then shouldn't the code be ??

    SRecord* Record1 = (SRecord*)arg1;
    SRecord* Record2 = (SRecord*)arg2;

PS in light of ovidiucucu's post #3 stating that the elements of m_arrRecord are pointers to SRecord and not objects of SRecord, then my above assumption re what .Getdata() returns isn't right.

[ovidiucucu]

The elements of m_arrRecord are pointers and not objects of SRecord type.
So, you have to pass sizeof(SRecord*) and not sizeof(SRecord).

[mesajflaviu]

"What is the type of m_arrRecord.GetData() ?"
void**
"then shouldn't the code be ??"
I have already tried that, doesn't worked, crash the program here:

SRecord* Record1 = (SRecord*)arg1;

and led me here:

CStringData* GetData() const throw()
{
    return( reinterpret_cast< CStringData* >( m_pszData )-1 );  // the crash lead me on this line 
}

[mesajflaviu]

The elements of m_arrRecord are pointers and not objects of SRecord type.
So, you have to pass sizeof(SRecord*) and not sizeof(SRecord).

Ovidiu, it works now !! Kindly thank you again !!!