MQL debug

mql_debug is additional instrument for code debugging for mql language. With mql_debug you can save result of your function and code of call function like a string to file or print to MetaTrader: Terminal\Experts

Installing

Download repo and copy mql_debug/Include/debug.mqh folder to <TERMINAL DIR>/MQL(4/5)/Include

Usage

Add include <debug/debug.mqh> and use _d wrapper to save result of function call:

#include <debug/debug.mqh>

int OnInit(){
    _d(MathPow(2, 1) + MathAbs(-10) / 2);
    _d(StringFormat("Length of 1234567890 = %d", StringLen("1234567890")));
}

Compile and run this your expert in terminal in a window of any trading pair and look debug result in <TERMINAL DIR>/Files/debug/<ACCOUNT NUMBER>/debug.txt. You can see something like:

MyExpert.mq4: int OnInit(), line 3:
    MathPow(2,1)+MathAbs(-10)/2 :: 7
MyExpert.mq4: int OnInit(), line 4:
    StringFormat(Length of 1234567890 = %d,StringLen(1234567890)) :: Length of 1234567890 = 10

In log file you can see next information:

• file, function and line of _d call,
• string of function call and its result after ::,

You can use any nesting _d calls:

#include <debug/debug.mqh>

int OnInit(){
    _d(_d(MathPow(2, 1)) + _d(MathAbs(-10) / 2));
}

Result of run this code:

TestDebug.mq4: int OnInit(), line 3:
    MathPow(2,1) :: 2
TestDebug.mq4: int OnInit(), line 3:
    MathAbs(-10)/2 :: 5
TestDebug.mq4: int OnInit(), line 3:
    MathPow(2,1)+MathAbs(-10)/2 :: 7

First, the _d() run with the deepest nesting, and then higher.

In any time in code you can change a name of debug log file with method _d_set_log_path():

#include <debug/debug.mqh>

int OnInit(){
    _d(MathPow(2, 1));
    _d_set_log_path("example_debug.txt");
    _d(MathAbs(-10));
}

After run code you get two result files:

1. <TERMINAL DIR>/Files/debug/<ACCOUNT NUMBER>/debug.txt:
TestDebug.mq4: int OnInit(), line 3:
    MathPow(2,1) :: 2

2. <TERMINAL DIR>/Files/example_debug.txt:
TestDebug.mq4: int OnInit(), line 3:
    MathAbs(-10) :: 10

To clear debug file, use method _d_clear():

#include <debug/debug.mqh>

int OnInit(){
    _d(MathPow(2, 1));
    _d_clear();
    _d(MathAbs(-10));
}

It is useful when you debug your code in MetaEditor and want to clear result file.

Debug to terminal journal

In most cases, the saving of results to file is better case, but you can print debug result to terminal journal (section: Terminal\Experts) using _dp():

#include <debug/debug.mqh>

int OnInit(){
    _dp(MathPow(2, 3));
}

After run code you can see result in journal like:

2021.02.28 13:50:25.956	MyExpert EURUSD,H1: MyExpert.mq4: int OnInit(), line 43:    MathPow(2,3) :: 8

Usage of some debugs

Using _d and _dp you work with default debug.
You can define some debug for flex usage, adding Debug object and calling d and df methods:

#include <debug/debug.mqh>

int OnInit(){
    // first debug
    Debug d_1("debug_1.txt");

    d(d_1, MathPow(4, 1));
    dp(d_1, MathPow(4, 2));
    
    // second debug
    Debug d_2("debug_2.txt");

    d(d_2, MathPow(4, 1));
    dp(d_2, MathPow(4, 2));
}

You can use a default and custom debugs at the same time.

To change path to result file, use d_set_log_path(d_object, log_path).

To clear result file, use d_clear(d_object).

Synonyms

Instead of usage _d you can use _df - they are equivalent. _df is added for common code style, if anybody wants to write so. In most cases it is used the saving to file, so _d is used for brevity.

For your custom debug objects there is appropriate df.

Run tests

1. Copy mql_debug/Experts/TestDebug.mq4 to <TERMINAL DIR>/MQL(4/5)/Experts
2. Compile TestDebug.mq4 and run TestDebug.ex4 in terminal in a window of any trading pair.
3. Look test result in <TERMINAL DIR>/Files/TestDebug_unit_test_log.txt

CONTRIBUTING

To reporting bugs or suggest improvements, please use the issue tracker.

Thank you very much, that you would like to contribute to mql_debug. Thanks to the present, past and future contributors.

If you think you have discovered a security issue in our code, please do not create issue or raise it in any public forum until we have had a chance to deal with it. For security issues use [email protected]

LINKS

• Project's home: https://github.com/vivazzi/mql_debug
• Report bugs and suggest improvements: https://github.com/vivazzi/mql_debug/issues
• Author's site, Artem Maltsev: https://vivazzi.pro

LICENCE

Copyright © 2021 Artem Maltsev and contributors.

MIT licensed.