MQL4 Reference Constants, Enumerations and Structures Named Constants Predefined Macro Substitutions

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Predefined Macro Substitutions

To simplify the debugging process and obtain information about operation of a mql4-program, there are special macro constant, values of which are set at the moment of compilation. The easiest way to use these constants is outputting values by the Print() function, as it's shown in the example.

Constant

Description

__DATE__

File compilation date without time (hours, minutes and seconds are equal to 0)

__DATETIME__

File compilation date and time

__LINE__

Line number in the source code, in which the macro is located

__FILE__

Name of the currently compiled file

__PATH__

An absolute path to the file that is currently being compiled

__FUNCTION__

Name of the function, in whose body the macro is located

__FUNCSIG__

Signature of the function in whose body the macro is located. Logging of the full description of functions can be useful in the identification of overloaded functions

__MQLBUILD__, __MQL4BUILD__

Compiler build number

Example:

#property copyright "Copyright © 2009, MetaQuotes Software Corp."
#property link      "https://www.metaquotes.net"
//+------------------------------------------------------------------+
//| Expert initialization function                                   |
//+------------------------------------------------------------------+
void OnInit()
  {
//--- an example of information output at Expert Advisor initialization
   Print(" __FUNCTION__ = ",__FUNCTION__,"  __LINE__ = ",__LINE__);
//--- set the interval between the timer events
   EventSetTimer(5);
//---
  }
//+------------------------------------------------------------------+
//| Expert deinitialization function                                 |
//+------------------------------------------------------------------+
void OnDeinit(const int reason)
  {
//--- an example of information output at Expert Advisor deinitialization
   Print(" __FUNCTION__ = ",__FUNCTION__,"  __LINE__ = ",__LINE__);
//---
  }
//+------------------------------------------------------------------+
//| Expert tick function                                             |
//+------------------------------------------------------------------+
void OnTick()
  {
//--- information output at tick receipt
   Print(" __MQLBUILD__ = ",__MQLBUILD__,"  __FILE__ = ",__FILE__);
   Print(" __FUNCTION__ = ",__FUNCTION__,"  __LINE__ = ",__LINE__);
   test1(__FUNCTION__);
   test2();
//---
  }
//+------------------------------------------------------------------+
//| test1                                                            |
//+------------------------------------------------------------------+
void test1(string par)
  {
//--- information output inside the function
   Print(" __FUNCTION__ = ",__FUNCTION__,"  __LINE__ = ",__LINE__," par = ",par);
  }
//+------------------------------------------------------------------+
//| test2                                                            |
//+------------------------------------------------------------------+
void test2()
  {
//--- information output inside the function
   Print(" __FUNCTION__ = ",__FUNCTION__,"  __LINE__ = ",__LINE__);
  }
//+------------------------------------------------------------------+
//| OnTimer event handler                                            |
//+------------------------------------------------------------------+
void OnTimer()
  {
//---
   Print(" __FUNCTION__ = ",__FUNCTION__,"  __LINE__ = ",__LINE__);
   test1(__FUNCTION__);
  }
//+------------------------------------------------------------------+