code: function _fnGetCellData( oSettings, iRow, iCol, sSpecific )
  	{
  		var oCol = oSettings.aoColumns[iCol];
  		var oData = oSettings.aoData[iRow]._aData;
  		var sData = oCol.fnGetData( oData, sSpecific );
  	
  		if ( sData === undefined )
  		{
  			if ( oSettings.iDrawError != oSettings.iDraw && oCol.sDefaultContent === null )
  			{
  				_fnLog( oSettings, 0, "Requested unknown parameter "+
  					(typeof oCol.mData=='function' ? '{function}' : "'"+oCol.mData+"'")+
  					" for row "+iRow, 4 );
  				oSettings.iDrawError = oSettings.iDraw;
  			}
  			return oCol.sDefaultContent;
  		}
  	
  		/* When the data source is null, we can use default column data */
  		if ( (sData === oData || sData === null) && oCol.sDefaultContent !== null )
  		{
  			sData = oCol.sDefaultContent;
  		}
  		else if ( typeof sData === 'function' )
  		{
  			// If the data source is a function, then we run it and use the return
  			return sData();
  		}
  	
  		if ( sData === null && sSpecific == 'display' )
  		{
  			return '';
  		}
  		return sData;
  	}
docs: Get the data for a given cell from the internal cache, taking into account data mapping
  @param {object} oSettings dataTables settings object
  @param {int} iRow aoData row id
  @param {int} iCol Column index
  @param {string} sSpecific data get type ('display', 'type' 'filter' 'sort')
  @returns {*} Cell data
  @memberof DataTable#oApi