mruby Documentation

Getting Started

New to mruby? Start here:

Document	Description
Getting Started	Build mruby and run your first program
Language Features	Ruby subset supported by mruby
Limitations	Behavioral differences from CRuby

Guides (for embedders and gem authors)

Embedding mruby in C

Document	Description
C API Reference	Values, classes, methods, error handling, fibers
GC Arena	Managing temporary objects in C extensions
Linking	Linking with libmruby
Amalgamation	Single-file build for easy integration
Precompiled Symbols	Compile-time symbol allocation

Building and Configuring

Document	Description
Compilation	Build system, cross-compilation, toolchains
Build Configuration	Compile-time macros (MRB_* flags)
mrbgems	Creating and managing gems
Memory	Allocator customization and heap regions

Tools

Document	Description
Debugger	Using mrdb for debugging
ROM Method Tables	Read-only method tables for constrained devices

Reference

Document	Description
Directory Structure	Source tree layout

Internals (for mruby contributors)

Start with Architecture for an overview, then dive into the subsystem you need:

Document	Description
Architecture	Overview of object model, VM, GC, compiler
Virtual Machine	Dispatch loop, call frames, method lookup, fibers
Garbage Collector	Tri-color marking, write barriers, generational GC
Compiler Pipeline	Parser, code generator, IRep, binary format
Opcodes	VM instruction set reference
Value Boxing	How mrb_value encodes types

Release Notes

• mruby 3.4
• mruby 3.3
• mruby 3.2
• mruby 3.1
• mruby 3.0