Standard Library Utilities

Language-level reference for MQL4/MQL5 standard library functions, runtime utilities, and development conventions.

This is a Reference skill: the body is a routing table into references/. Read the relevant reference file for the function family you need.

Purpose

Catalogs the MQL5 standard library and runtime utility surface — everything from string manipulation and file I/O to database access, math functions, and terminal global variables. The initial "Development Standards" section covers EA structure conventions, input parameter grouping, error handling patterns, .set file presets, and MQL4 vs MQL5 differences.