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Standard Errors

30 March 2018, 11:31

Ziheng Zhuang

120

The mqh library for MQL5 includes two functions for obtaining error information.

string ErrorDescription(int code) : the function returns the description of error code.
string ErrorConstant(int code) : the function returns the string of the enum constant.

//+------------------------------------------------------------------+
//|                                           test_standarderros.mq5 |
//|                        Copyright 2018, MetaQuotes Software Corp. |
//|                                             https://www.mql5.com |
//+------------------------------------------------------------------+
#property copyright "Copyright 2018, MetaQuotes Software Corp."
#property link      "https://www.mql5.com"
#property version   "1.00"
#include <StandardErrors.mqh>
//+------------------------------------------------------------------+
//| Script program start function                                    |
//+------------------------------------------------------------------+

void OnStart()
  {
//---
   int code; //=GetLastError();
   code=10010;
   printf("error code = %d, description = %s",code,ErrorDescription(code));
   printf("error code = %d, constant string = %s",code,ErrorConstant(code));

   SetUserError(100);
   code=GetLastError();

   Print("error code =",code,"  ---  ",ErrorDescription(code));
   Print("error code =",code,"  ---  ",ErrorConstant(code));
  }
//+------------------------------------------------------------------+
//test result:
//error code = 10010, description = Only part of the request was completed
//error code = 10010, constant string = TRADE_RETCODE_DONE_PARTIAL
//error code =65636  ---  User error 100
//error code =65636  ---  USER ERROR 100

Trade error from trade server:

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

Runtime error:

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

Files:

StandardErrors.mqh 67 kb

test_StandardErros.mq5 2 kb

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Ziheng Zhuang 2018.03.30 09:40 #1

The identical library has been published recently https://www.mql5.com/en/code/20305

Also, there is another one by MetaQuotes Software Corp. published long ago https://www.mql5.com/en/code/79

coachklso 2018.05.30 20:17 #2

I am trying to run an EA on my mt4 platform. When I load it and go to the dependencies it shows that there is a string error description (int)

How do I fix this

Ziheng Zhuang 2018.05.31 02:31 #3

coachklso:

I am trying to run an EA on my mt4 platform. When I load it and go to the dependencies it shows that there is a string error description (int)

How do I fix this

Hello, this library is for MT5 instead of MT4.

for MT4 EA,an example as below:

//+------------------------------------------------------------------+
//|                                                  test_stdlib.mq4 |
//|                                          Copyright 2018,fxMeter. |
//|                            https://www.mql5.com/en/users/fxmeter |
//+------------------------------------------------------------------+
#property copyright "Copyright 2018,fxMeter."
#property link      "https://www.mql5.com/en/users/fxmeter"
#property version   "1.00"
#property strict
#include <stdlib.mqh>
//+------------------------------------------------------------------+
//| Expert initialization function                                   |
//+------------------------------------------------------------------+
int OnInit()
  {
//---
   
//---
   return(INIT_SUCCEEDED);
  }
//+------------------------------------------------------------------+
//| Expert deinitialization function                                 |
//+------------------------------------------------------------------+
void OnDeinit(const int reason)
  {
//---
   
  }
//+------------------------------------------------------------------+
//| Expert tick function                                             |
//+------------------------------------------------------------------+
void OnTick()
  {
//---
      int error = GetLastError();
      string str = ErrorDescription(error);   
  }
//+------------------------------------------------------------------+