MT5/mql5 reported and confirmed bugs. - page 10

I found a spelling error, not sure, if this is considered a bug, but I would guess it exists already quite a while.

if(GetLastError() == ERR_RESOURCE_UNSUPPOTED_TYPE)
{
        printf("%s", "Unsupported resource type");
}

The constant "ERR_RESOURCE_UNSUPPOTED_TYPE" sould be spelled ERR_RESOURCE_UNSUPPORTED_TYPE.

Nether the less, there are quie some constants which are not declared/defined, but documented...

List of not defined/declared constants, but documented in docs here:

https://www.mql5.com/en/docs/constants/errorswarnings/errorcodes

ERR_FTP_CLOSED
ERR_DATABASE_INTERNAL_DB
ERR_DATABASE_INTERRUPT
ERR_DATABASE_NOTFOUND
ERR_DATABASE_EMPTY
ERR_DATABASE_NOLFS
ERR_DATABASE_FORMAT
TRADE_RETCODE_FIFO_ONLY

Without restarting the terminal.

#define PRINT(A) Print(#A + " = " + (string)(A))
 
void OnStart()
{
  const string Name = "Name";
  
  ObjectCreate(0, Name, OBJ_VLINE, 0, D'2023.01.02', 0);
  ObjectSetString (0, Name, OBJPROP_TOOLTIP, "This is a tooltip");
  
  Print("\nCurrent Chart:");
  PRINT((datetime)ObjectGetInteger(0, Name, OBJPROP_TIME));
  PRINT(ObjectGetString(0, Name, OBJPROP_TOOLTIP));
  
  const ulong Chart = ChartOpen(_Symbol, _Period);
  const string FileName = "\\Files\\FileName.tpl";
  
  if (ChartSaveTemplate(0, FileName) && ChartApplyTemplate(Chart, FileName))
  {    
    ChartGetInteger(Chart, CHART_WINDOW_HANDLE);
    
    Print("\nNew Chart:");
    PRINT((datetime)ObjectGetInteger(Chart, Name, OBJPROP_TIME));
    PRINT(ObjectGetString(Chart, Name, OBJPROP_TOOLTIP));
  }
}

Current Chart:
(datetime)ObjectGetInteger(0,Name,OBJPROP_TIME) = 2023.01.02 00:00:00
ObjectGetString(0,Name,OBJPROP_TOOLTIP) = This is a tooltip

New Chart:
(datetime)ObjectGetInteger(Chart,Name,OBJPROP_TIME) = 2023.01.02 00:00:00
ObjectGetString(Chart,Name,OBJPROP_TOOLTIP) = 

Metaquotes developer answer :

The generic libraries don't allow to cover all situations (primitive,structs,objects) in one template class.

I think the reason is this:

template<typename T>
class MyStack
  {
private:
   T                 m_arr[];
   int               m_index;
public:
   void              MyStack(const int size=16)
     {
      ArrayResize(m_arr,size);
      m_index=WRONG_VALUE;
     }
   bool              Push(T const &item)
     {
      m_index++;
      m_arr[m_index]=item;
      return true;
     }
  };
MyStack<int> stki;
//+------------------------------------------------------------------+
//| Script program start function                                    |
//+------------------------------------------------------------------+
void OnStart()
  {

//---
   stki.Push(5);
  }

The compile says:

Because the variable is declared by reference, there's a possibility that the Push method will change it's value, which should reflect in the caller side and for this reason it does not allow to pass '5' by reference. But as you can see I added 'const' to the parameter definition in the Push method, which takes the sting out of the reason to not allow that (in C++ it's allowed).

That's not really a bug but an mql limitation.

Anyway, I do agree with you it would be good to be able to create really generic code.

Unfortunately, this is far from the only problem in doing so.