Stdlib (Standard Library)
Official MetaQuotes MQL4 foundation library · Ships with MT4 · Free
About Stdlib (Standard Library)
The Stdlib library, published officially by MetaQuotes (the creator of MetaTrader itself) on the MQL5 Code Base, is a foundational MQL4 library that ships as a natural part of every MetaTrader 4 installation, included via files such as stdlib.mqh, stderror.mqh, and WinUser32.mqh using the #include directive.
It's not always necessary to include every file — for example, stderror.mqh only needs to be included if a program actually handles error-code processing. It serves as an example/reference library demonstrating standard MQL4 library functionality and error-code definitions, forming part of the core foundation many custom EAs and indicators are built on top of.
- Platform: MetaTrader 4
- Type: Official standard library (foundational EA/indicator building block)
- Included files: stdlib.mqh, stderror.mqh, WinUser32.mqh
- Publisher: MetaQuotes (official)
- Price: Free, ships with MT4
- Source: mql5.com Code Base · Stdlib library by MetaQuotes
Key Features
✓ Officially published by MetaQuotes — maximum authenticity and reliability as a foundation library
✓ Ships automatically with every MT4 installation — no separate download needed for most users
⚠ This is a developer-facing library, not a trading strategy — it's a building block other EAs/indicators use, not something you attach to a chart directly for signals