CopyBuffer() error

Nekad Prob 2022.09.13 18:03

hello,

i tried to use copybuffer function, that every new bar, it will copy totalbars numbers.

and when not new bar, it only copy the last bar data.

but it give me out of range error.

how to fix it?

here is my code, please check it for me.

thanks in advance.

//+------------------------------------------------------------------+
//|                                                        Tanya.mq5 |
//|                                                                  |
//|                                                                  |
//+------------------------------------------------------------------+
#property copyright ""
#property link      ""
#property version   "1.00"
#define  TOTALBARS   200
double maArray[];
int handle=iMA(_Symbol,_Period,21,0,MODE_EMA,PRICE_CLOSE);
string comstring="";
//+------------------------------------------------------------------+
//| Expert initialization function                                   |
//+------------------------------------------------------------------+
int OnInit()
  {
//---
   
//---
   return(INIT_SUCCEEDED);
  }
//+------------------------------------------------------------------+
//| Expert deinitialization function                                 |
//+------------------------------------------------------------------+
void OnDeinit(const int reason)
  {
//---
   
  }
//+------------------------------------------------------------------+
//| Expert tick function                                             |
//+------------------------------------------------------------------+
void OnTick()
  {
//---
   int j,toCopy;
   if(isNewBar()) toCopy=TOTALBARS;
   else toCopy=1;
   
   if(CopyBuffer(handle,0,0,toCopy,maArray)<=0) return;
   
   for(j=0;j<10;j++)
      comstring+="\n"+DoubleToString(maArray[j],_Digits);
   
   Comment(comstring);
  }
//+------------------------------------------------------------------+
bool isNewBar()
  {
   static datetime prevTime=0;
   datetime currTime=(datetime)SeriesInfoInteger(_Symbol,_Period,SERIES_LASTBAR_DATE);
   if(prevTime!=currTime)
     {
      prevTime=currTime;
      return(true);
     }
   return(false);
  }

Tobias Johannes Zimmer 2022.09.13 21:16 #1

You should run debug, it will show you for example

"out of range (138,28)"

Which means the error happened in line 138, letter 28 (counting the letters from the line beginning).

Maybe when you do this you will already have an idea what is the problem. If not post a screenshot of the error here with line and letter.

What are these 2 Any rookie question, so MQ5 Indicator - Array

Nekad Prob 2022.09.14 02:50 #2

thanks to reply.

the problem is when i use maArray to displayed on comment

on this line:

      comstring+="\n"+DoubleToString(maArray[j],_Digits);

even i tried to call maArray[1], the error is still there..

Nekad Prob 2022.09.14 04:22 #3

ok fiexed..
have to use static array..

double maArray[TOTALBARS];

thankyou for help me..

Tobias Johannes Zimmer 2022.09.14 10:45 #4

Yes that works too, but with a dynamic array you can also just ArrayResize() the array to TOTALBARS in OnInit.

It had no fields to store information in.

William Roeder 2022.09.14 13:25 #5

double maArray[];
int handle=iMA(_Symbol,_Period,21,0,MODE_EMA,PRICE_CLOSE);

That is not an assignment; it's initialization of a common (globally declared), or static variable with a constant. They work exactly the same way in MT4/MT5/C/C++.
1. They are initialized once on program load.
2. They don't update unless you assign to them.
3. In C/C++ you can only initialize them with constants, and they default to zero. In MTx you should only initialize them with constants. There is no default in MT5, or MT4 with strict (which you should always use).
  
  MT4/MT5 actually compiles with non-constants, but the order that they are initialized is unspecified and don't try to use any price (or indicator) or server related functions in OnInit (or on load or in OnTimer before you've received a tick), as there may be no connection/chart yet:
  1. Terminal starts.
  2. Indicators/EAs are loaded. Static and globally declared variables are initialized. (Do not depend on a specific order.)
  3. OnInit is called.
  4. For indicators OnCalculate is called with any existing history.
  5. Human may have to enter password, connection to server begins.
  6. New history is received, OnCalculate called again.
  7. A new tick is received, OnCalculate/OnTick is called. Now TickValue, TimeCurrent, account information and prices are valid.
4. Unlike indicators, EAs are not reloaded on chart change, so you must reinitialize them, if necessary.
  external static variable - MQL4 programming forum #2 (2013)
Perhaps you should read the manual, especially the examples.
   How To Ask Questions The Smart Way. (2004)
      How To Interpret Answers.
         RTFM and STFW: How To Tell You've Seriously Screwed Up.

They all (including iCustom) return a handle (an int). You get that in OnInit. In OnTick/OnCalculate (after the indicator has updated its buffers), you use the handle, shift and count to get the data.
          Technical Indicators - Reference on algorithmic/automated trading language for MetaTrader 5
          Timeseries and Indicators Access / CopyBuffer - Reference on algorithmic/automated trading language for MetaTrader 5
          How to start with MQL5 - General - MQL5 programming forum - Page 3 #22 (2020)
          How to start with MQL5 - MetaTrader 5 - General - MQL5 programming forum - Page 7 #61 (2020)
          MQL5 for Newbies: Guide to Using Technical Indicators in Expert Advisors - MQL5 Articles (2010)
          How to call indicators in MQL5 - MQL5 Articles (2010)

"access to non-static member My Error : { Cannot preload bollingers data

Nekad Prob 2022.09.23 04:24 #6

William Roeder #:

That is not an assignment; it's initialization of a common (globally declared), or static variable with a constant. They work exactly the same way in MT4/MT5/C/C++.
1. They are initialized once on program load.
2. They don't update unless you assign to them.
3. In C/C++ you can only initialize them with constants, and they default to zero. In MTx you should only initialize them with constants. There is no default in MT5, or MT4 with strict (which you should always use).
  
  MT4/MT5 actually compiles with non-constants, but the order that they are initialized is unspecified and don't try to use any price (or indicator) or server related functions in OnInit (or on load or in OnTimer before you've received a tick), as there may be no connection/chart yet:
  1. Terminal starts.
  2. Indicators/EAs are loaded. Static and globally declared variables are initialized. (Do not depend on a specific order.)
  3. OnInit is called.
  4. For indicators OnCalculate is called with any existing history.
  5. Human may have to enter password, connection to server begins.
  6. New history is received, OnCalculate called again.
  7. A new tick is received, OnCalculate/OnTick is called. Now TickValue, TimeCurrent, account information and prices are valid.
4. Unlike indicators, EAs are not reloaded on chart change, so you must reinitialize them, if necessary.
  external static variable - MQL4 programming forum #2 (2013)
Perhaps you should read the manual, especially the examples.
   How To Ask Questions The Smart Way. (2004)
      How To Interpret Answers.
         RTFM and STFW: How To Tell You've Seriously Screwed Up.

They all (including iCustom) return a handle (an int). You get that in OnInit. In OnTick/OnCalculate (after the indicator has updated its buffers), you use the handle, shift and count to get the data.
          Technical Indicators - Reference on algorithmic/automated trading language for MetaTrader 5
          Timeseries and Indicators Access / CopyBuffer - Reference on algorithmic/automated trading language for MetaTrader 5
          How to start with MQL5 - General - MQL5 programming forum - Page 3 #22 (2020)
          How to start with MQL5 - MetaTrader 5 - General - MQL5 programming forum - Page 7 #61 (2020)
          MQL5 for Newbies: Guide to Using Technical Indicators in Expert Advisors - MQL5 Articles (2010)
          How to call indicators in MQL5 - MQL5 Articles (2010)

ok...
many thanks for your correction..
next i'll try to code properly...

thank you very much...
i really appreciate it..

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