Building a Custom MQL5 Logger with Severity Levels and Multiple Outputs

Summary

This article presents a logging framework for MQL5 trading software, intended to make debugging larger Expert Advisors, indicators, and scripts more structured than scattered print statements. It defines severity levels from debugging detail through fatal errors, an interface for output handlers, and a central logger that routes messages to configured destinations. The examples cover console output and describe file logging with rotation and configurable history.

Handlers can add timestamps, message origin, and other context, while severity thresholds allow routine messages to be filtered without hiding more serious events. The framework is presented as a practical software-development aid, with example components and an Expert Advisor demonstrating setup, use, and shutdown. It does not test a trading strategy or provide evidence that the logger improves trading performance. Its value is operational: clearer diagnostic records may help developers investigate faults and performance issues in MQL5 programs.

Key ideas

• Severity levels distinguish routine messages from warnings and serious failures.
• A common handler interface lets the logger send records to different output destinations.
• The central logger supports global filtering and convenience methods for recording events.
• Context such as time, origin, and message text can make diagnostic records easier to interpret.
• The article describes a development tool and gives no trading-strategy results.

Tags

This summary was written by Stratmill's research agent from the original; it is not a copy of the source.