MQL Plus Enhanced Error Handler Support - library for MetaTrader 5

Change-Log 4.2

• Bugfixes, compatibilitishues resolved.
• Fixed error in UserErrorHandler function signature.

Change-Log 4.0

• Recreated the whole code structure to support shared library compilation as wel las header include compilation
• Supports external CSV-File as supply for mql error codes
• Is MQL4 compatible
• All MQL4 and MQL5 Languages are included
• Supports MQL API function shadowing to be turned on or off

From now on the project is distributed as shared project over MQL cloud storage. You are welcome to contribute to the code.

You will need "MQLplus Include Library Collection" Project. optionally add the "MQLplus Enhanced Error Handler Library" Project to your files to have the shared binary library compiled as well as get an example project, showing the usage of the library.

Change-Log 3.12

• Massive improvements to all aspects of the errror code generation and handling
• Compatibility with MQL4 integrated
• Support for user supplied OnError() function definition, see beginning of lib_error.mql-file
• Overwrite Built-In function SetUserError()
• Translation of error messages to almost all supported languages by MQL

Current Version 3.12

Encapsulates error code and text handling.

Supported features:

• User defined error codes
• Error code groups
• Customizable output string
• Seemless integration

Error code handling and error code resolving to text messages is a pain. This include file will solve some of the daily issues of handling error codes.

Example output:

This output was produced by ObjectGetInteger() in exaple code below.

Example code:

/////////////////////////////////////////
//
//  Handle user specified warning codes 
//  as errors.
//
#define LIB_ERR_LEVEL_WARNING_AS_ERROR
#include <mqlplus/lib_error.mqh>


/*
*********************************************************************************************************
*  Provider return codes                                                                                *
*********************************************************************************************************
*/

// Define error group id
#define EA_ERRGROUP_CODE_EA_CORE            0x01

// Defined return codes
#define CORE_SUCCESS                            LIB_ERROR_CODE(EA_ERRGROUP_CODE_EA_CORE, 0x00)
#define CORE_INFO_CORE_READY                    LIB_ERROR_CODE_HANDLED(EA_ERRGROUP_CODE_EA_CORE, 0x01)
#define CORE_WARN_PENDING_OPERATION             LIB_ERROR_CODE_WARNING(EA_ERRGROUP_CODE_EA_CORE, 0x01)

// Define message resolver
LIB_ERR_REGISTER_RESOLVER_BEGIN(EA_ERRGROUP_CODE_EA_CORE)
    LIB_ERR_REGISTER_RESOLVER_MSGCODE(CORE_SUCCESS,                     "CORE_SUCCESS",                     "Operation success. An order has been processed.")
    LIB_ERR_REGISTER_RESOLVER_MSGCODE(CORE_INFO_CORE_READY,             "CORE_INFO_CORE_READY",             "Expert advisor: Core ready.")
    LIB_ERR_REGISTER_RESOLVER_MSGCODE(CORE_WARN_PENDING_OPERATION,      "CORE_WARN_PENDING_OPERATION",      "A pending operation is awaiting confirmation.")
LIB_ERR_REGISTER_RESOLVER_END(EA_ERRGROUP_CODE_EA_CORE)








//+------------------------------------------------------------------+
//| Expert initialization function                                   |
//+------------------------------------------------------------------+
int OnInit()
  {
//---

    // Set a user defined error code
    SetUserError(CORE_INFO_CORE_READY);

   
//---
   return(INIT_SUCCEEDED);
  }




//+------------------------------------------------------------------+
//| Expert deinitialization function                                 |
//+------------------------------------------------------------------+
void OnDeinit(const int reason)
  {
//---

    // Perform some check    
    check_for_pending_orders();

    // Retrieve error code and display its text
    OnError();
    



//---
   return;
  }



//+------------------------------------------------------------------+
//| Expert tick function                                             |
//+------------------------------------------------------------------+
void OnTick()
  {
//---

    // Retrieve the error code
    int err_code = NULL;

    // Update some state by function
    if( (!some_function())
     && (OnError(err_code)) )   // Display error message in journal and retrieve its corresponding error number
    {
        // Last error code is saved in err_code

        return;
    }


    // Continue processing


//---
    return;   
  }
//+------------------------------------------------------------------+




//+------------------------------------------------------------------+
//| check_for_pending_orders()                                       |
//+------------------------------------------------------------------+
void check_for_pending_orders()
  {
//---

    // Set a user defined error code
    SetUserError(CORE_WARN_PENDING_OPERATION);


//---
   return;
  }



//+------------------------------------------------------------------+
//| some_function()                                                  |
//+------------------------------------------------------------------+
bool some_function()
  {
//---
    // Error status
    bool err = false;


    // Perform some eventually failing operation
    err |= (!err) && !ObjectGetInteger(ChartID(), "", OBJPROP_COLOR) && OnError(__LINE__);


    // Set a user defined error code
    err |= (!err) && SetUserError(CORE_SUCCESS);

//---
   return(!err);
  }