ErrorDescription - libreria per MetaTrader 5

La libreria contiene le seguenti funzioni:

• TradeServerReturnCodeDescription - restituisce la descrizione di codici di ritorno del server di trading;
• ErrorDescription - restituisce la descrizione di runtime errors.

//+------------------------------------------------------------------+
//|                                             ErrorDescription.mqh |
//|                        Copyright 2010, MetaQuotes Software Corp. |
//|                                              http://www.mql5.com |
//+------------------------------------------------------------------+
#property copyright "2010, MetaQuotes Software Corp."
#property link      "http://www.mql5.com"
#property version   "1.00"
//+------------------------------------------------------------------+
//| returns trade server return code description                     |
//+------------------------------------------------------------------+
string TradeServerReturnCodeDescription(int return_code)
//+------------------------------------------------------------------+
//| returns runtime error code description                           |
//+------------------------------------------------------------------+
string ErrorDescription(int err_code)

Esempio:

(Non dimenticare di copiare il file ErrorDescription.mq5 nella directory \MetaTrader 5\MQL5\Include)

//+------------------------------------------------------------------+
//|                                               ErrorDescrTest.mq5 |
//|                        Copyright 2010, MetaQuotes Software Corp. |
//|                                              http://www.mql5.com |
//+------------------------------------------------------------------+
#property copyright "2010, MetaQuotes Software Corp."
#property link      "http://www.mql5.com"
#property version   "1.00"
#include <ErrorDescription.mqh>
//+------------------------------------------------------------------+
//| Example of use of the ErrorDescription.mqh library               |
//+------------------------------------------------------------------+
void OnStart()
  {
   Print("----- Description of trade server return codes -----");
   for(int i=10004;i<=10034;i++)
     {
      Print("Trade server return code:",i,TradeServerReturnCodeDescription(i));
     }
   Print("-------- Description of runtime error codes ---------");
   for(int i=4001;i<=4014;i++)
     {
      Print("Runtime error code:",i,ErrorDescription(i));
     }
  }
//+------------------------------------------------------------------+

In alcuni casi è necessario lavorare con errori definiti dall'utente. Nel MQL5 c'è una funzione SetUserError, che imposta la variabile predefinita _LastError nel valore di ERR_USER_ERROR_FIRST + user_error.

I codici di errore definiti dall'utente partono dal codice ERR_USER_ERROR_FIRST. In questi casi potete usare la funzione ErrorDescriptionExt per restituire la descrizione degli errori, compresi gli errori definiti dall'utente:

//+------------------------------------------------------------------+
//|                                               UserErrorDescr.mq5 |
//|                        Copyright 2010, MetaQuotes Software Corp. |
//|                                              http://www.mql5.com |
//+------------------------------------------------------------------+
#property copyright "2010, MetaQuotes Software Corp."
#property link      "http://www.mql5.com"
#property version   "1.00"
#include <ErrorDescription.mqh>
//+------------------------------------------------------------------+
//|  returns runtime error code description,                         |
//|  with user defined errors                                        |
//+------------------------------------------------------------------+
string ErrorDescriptionExt(int err_code,string&user_errors[])
  {
   if(err_code>=0 && err_code<ERR_USER_ERROR_FIRST) return(ErrorDescription(err_code));
//--- user defined runtime errors
   err_code-=ERR_USER_ERROR_FIRST;
   if(err_code<=ArraySize(user_errors)) return(user_errors[err_code]);
//---
   return("Unknown error");
  };

// an array with description of the user defined runtime errors
string MyErrors[]=
  {
   "User error №1",
   "User error №2",
   "User error №3"
  };
//+------------------------------------------------------------------+
//| Script program start function                                    |
//+------------------------------------------------------------------+
void OnStart()
  {
//---
   for(int i=0;i<=2;i++)
     {
      SetUserError(i);
      Print("User defined error code:",i,ErrorDescriptionExt(GetLastError(),MyErrors));
     }
  }
//+------------------------------------------------------------------+