Libraries: CDictionary class - page 2

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nicholi shen:

I've discovered a bug in CDictionary. When you use the Reset Method it deletes the CList object in m_data. Subsequent calls to other methods that fetch the point from the dictionary receive a bad pointer in return. Example:



I would propose the following fix for all methods which use the key hash to access a CList object from the m_data array. 


Thanks nicoli shen. Your solution is the 'safer' one. However, I cannot reproduce the issue.

Another thing that bothers me related to this: an object pointer should be able to accept a null value. m_data is a dynamic array, so it should return null when an unfilled index from the array is retrieved, or the item stored is deleted. Storing data from m_data to CList* without checking the pointer beforehand is also done on other methods like Get() and Delete(), so the test scripts above should also fail if this issue exists. A simple assignment between one pointer and another can be done without any pointer access errors, even if the object the lvalue points to is already deleted:

#include <Object.mqh>
//+------------------------------------------------------------------+
//| Script program start function                                    |
//+------------------------------------------------------------------+
void OnStart()
  {
//---
   CObject *obj = new CObject();
   delete obj;
   CObject *obj1 = obj; //no invalid pointer access errors
  }
//+------------------------------------------------------------------+

The issue can be reduced to the example above. But in this case, there are no pointer errors. I am curious because I remember encountering this same problem in an earlier build, which was quickly patched.

I am currently using MT5 build 1932, but let me know if I am missing something.

 

I have these error:


'Key' - unexpected token, probably type is missing? Dictionary.mqh 39 23

'Key' - function already defined and has different type Dictionary.mqh 39 23

   see declaration of 'CDictionaryEntryBase::Key' Dictionary.mqh 20 22



trying to complie on build 3320

 
Sunfire #:

I have these error:


'Key' - unexpected token, probably type is missing? Dictionary.mqh 39 23

'Key' - function already defined and has different type Dictionary.mqh 39 23

   see declaration of 'CDictionaryEntryBase::Key' Dictionary.mqh 20 22



trying to complie on build 3320

Try putting the keyword "void" before the class method
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