Volume Check and Adjust

[anuj71]

Article URL : https://www.mql5.com/en/articles/2555#invalid_lot

I am getting Error 131

To resolve this, I am trying something like Volume Error Handling. It update value automatically.

   Buy_Lot_Size = MathMax(SymbolInfoDouble(buy_random_symbol, SYMBOL_VOLUME_MIN), MathMin(Buy_Lot_Size, SymbolInfoDouble(buy_random_symbol, SYMBOL_VOLUME_MAX)));
   Sell_Lot_Size = MathMax(SymbolInfoDouble(sell_random_symbol, SYMBOL_VOLUME_MIN), MathMin(Sell_Lot_Size, SymbolInfoDouble(sell_random_symbol, SYMBOL_VOLUME_MAX)));

or

   Buy_Lot_Size = MathMax(MarketInfo(buy_random_symbol, MODE_MINLOT), MathMin(Buy_Lot_Size, MarketInfo(buy_random_symbol, MODE_MAXLOT)));
   Sell_Lot_Size = MathMax(MarketInfo(sell_random_symbol, MODE_MINLOT), MathMin(Sell_Lot_Size, MarketInfo(sell_random_symbol, MODE_MAXLOT)));

Instead of

//+------------------------------------------------------------------+
//| Check the correctness of the order volume                        |
//+------------------------------------------------------------------+
bool CheckVolumeValue(double volume,string &description)
  {
//--- minimal allowed volume for trade operations
   double min_volume=SymbolInfoDouble(Symbol(),SYMBOL_VOLUME_MIN);
   if(volume<min_volume)
     {
      description=StringFormat("Volume is less than the minimal allowed SYMBOL_VOLUME_MIN=%.2f",min_volume);
      return(false);
     }

//--- maximal allowed volume of trade operations
   double max_volume=SymbolInfoDouble(Symbol(),SYMBOL_VOLUME_MAX);
   if(volume>max_volume)
     {
      description=StringFormat("Volume is greater than the maximal allowed SYMBOL_VOLUME_MAX=%.2f",max_volume);
      return(false);
     }

//--- get minimal step of volume changing
   double volume_step=SymbolInfoDouble(Symbol(),SYMBOL_VOLUME_STEP);

   int ratio=(int)MathRound(volume/volume_step);
   if(MathAbs(ratio*volume_step-volume)>0.0000001)
     {
      description=StringFormat("Volume is not a multiple of the minimal step SYMBOL_VOLUME_STEP=%.2f, the closest correct volume is %.2f",
                               volume_step,ratio*volume_step);
      return(false);
     }
   description="Correct volume value";
   return(true);
  }

But my both of the code is not working. What wrong with my code. it does exact same and even better than article URL. it also adjust the Volume size after comparison.

[Miguel Angel Vico Alba]

anuj71:

What you are raising has already been answered hundreds of times in the forum:

https://www.mql5.com/en/search#!keyword=error%20131