Errors, bugs, questions - page 1838

[Renat Fatkhullin]

This is normal and absolutely correct. You asked for the internal size (no payload) of a dynamic object.

Use ArraySize for dynamic objects and apply sizeof to static objects only. Sizeof is counted at compile time and is always a constant.

[fxsaber]

Renat Fatkhullin:

This is normal and absolutely correct.

Use ArraySize for dynamic objects and apply sizeof only to static objects.

Thank you! Please bring the Help to conform to this recommendation.

[Slava]

Read the documentation all the way through

Вычисления размера происходит на этапе компиляции.

[fxsaber]

I'm asking for help, I'm stumped myself. I've written this script to explain.

struct STRUCT 
{
  int a;
};

class CLASS
{
public:
  int a;
};

STRUCT f1()
{  
  static int i = 0;
  
  STRUCT Res;
  
  Res.a = i++;   
  
  return(Res);
}

CLASS* f2()
{
  static int i = 0;
  
  CLASS* Res = new CLASS;
  
  Res.a = i++;
  
  return(Res);
}

void OnStart()
{
  int i1 = f1().a + f1().a;  
  int i2 = f2().a + f2().a;
}

There is a structure and there is a similar class. I need, that after i2 calculation, the corresponding class objects will be deleted spontaneously, as it happens with structure objects, when the same i1 calculation is performed. How to do this?

[TheXpert]

fxsaber:

How do I do this?

Wrap it in a smart pointer, not sure it can be done with mql

[fxsaber]

Комбинатор:
Wrap it up in a smart pointer, not sure it can be done by mql

The problem itself is caused by the inability to return a complex structure. For example, if in the code above instead of int a; make string a;, then f1() will fail on return. That's why my eyes fell on classes, but there the described trap awaited.

[TheXpert]

Generally, you can override the constructor copy and operator=

This won't work for classes, they are supposed to be returned by pointer only, structures can be returned by value.

[fxsaber]

Комбинатор:

Generally, you can override the constructor copy and operator=

This won't work for classes, they are supposed to be returned by pointer only, structures can be returned by value.

Thank you! I was prevented from this solution by a recently removed restriction. Now it works

struct STRUCT
{
  string Str;

  template <typename T>
  void operator =( const T Value )
  {
    Print(__FUNCTION__);
  }
  
  void operator =( const STRUCT &Struct )
  {
    this.Str = Struct.Str;
  }
};

STRUCT f()
{
  STRUCT Res;
  
  return(Res);
}

void OnStart()
{
  f() = 1;
}

[pivomoe]

During optimization of the Expert Advisor I get the following error

The (0, 3) tested with error "critical runtime error 512 in OnTimer function (sleep function reaches end of test)" at 0:37:20.429 + history synchronization 0:00:43.395

Single test passes without errors.

Version of MT5 and MetaEditor is 1571.

[fxsaber]

pivomoe:

During optimization of the Expert Advisor I get the following error

The "critical runtime error 512 in OnTimer function (sleep function reaches end of test)" error at 0:37:20.429 + history synchronization 0:00:43.395

Remove the maximum amount of code from the Expert Advisor, so that the error is reproducible. And publish the remaining code.