[Qt-interest] error

[Yves Bailly]

Sujan Dasmahapatra wrote:
> I am writing like this for this error
> 
> Error:
> *** glibc detected *** double free or corruption (out):
> 0x0000000000768340 ***
> 
> ////////////////////////////////////////////////////////////////////////
> ////////
> //In the header file(tablewidget.h)
> QList <QTableWidgetIem *> item;
> QList <Geometry *> geometry;
> QList <QString> filenames;
> int count;
> 
> ////////////////////////////////////////////////////////////////////////
> //////////
> //In the source file (tablewidget.cpp)
> Void TableWidget::~TableWidget()
> {
> 	if(count>0) 
> 	{
> 		for(int i=0; i<count; i++)
> 		{
> 			delete item[count];
> 			delete geometry[count];
> 		}
> 
> 		count = 0;
> 	}
> 	
> }
> 
> 
> Void TableWidget::fileNameUpdate(QString filename, Geometry *geometry)
> {
> 	item[count] = new QTbaleWidgetItem(filename,0);
> 	filenames.append(filename);
> 	setItem(count,0,item[count]);
> 	geometry[count] = new Geometry;
> 	geometry[count] = geometry;
> 	count ++;
> }
> ////////////////////////////////////////////////////////////////////////
> ///////////////////
> 
> Can anyone plss tell whats the reason I am getting this error.

Because the code you posted is simply horrible.
- what is this type "Void"? I'm only aware of "void"... yes, C++ is
   case-sensitive ;
- in ~TableWidget(), why use a loop when you're deleting only
   one item, the one having index "count" (which is probably invalid,
   as valid indices for an array of size N are between [0, N-1]) ;
- can you explain what the hell you intended to do with
   geometry[count] = geometry ??? does it even compiles? if yes,
   which compiler are you using?

Today is a good day... let's try this:

void TableWidget::~TableWidget()
{
    foreach(QTableWidgetIem* one_item, item)
    {
       if ( one_item != 0 )
       {
          delete one_item;
       }
    }
}

void TableWidget::fileNameUpdate(QString filename,
                                  Geometry* geometry_param)
{
   item.append(new QTableWidgetIem(filename, 0));
   filenames.append(filename);
   setItem(item.size()-1, 0, item.last());
   geometry.append(geometry_param);
}

Beware of not naming functions parameters using names already used
before, as you did here... also, there's no need to keep an extra
"count" variable, the QList<> has its own.

Hope this helps.

-- 
     /- Yves Bailly - Software developper  -\
     \- Sescoi France http://www.sescoi.fr -/
"The possible is done. The impossible is being done. For miracles,
thanks to allow a little delay."