Packages

Packages are directories with a Cplus.toml, source modules, and optional tests, documentation, link metadata, and platform variants. Add a package with cpc pm add; see Modules and packages and Package manager for resolution and manifest rules.

Core library and data

• stdlib — collections, text, I/O, concurrency, async runtime pieces, files, networking, and platform shims.
• json — JSON parsing and serialization.
• sqlite — Connection and Statement; raw bindings are available as sqlite/raw.
• arena — growable bump allocator.
• static_arena — fixed-capacity allocator stored in the value itself, with no heap allocation.
• uuid and log — identifiers and structured logging.

Facet applications

• facet — platform-neutral UI tree, elements, components, screens, services, and navigation vocabulary.
• facet_runtime — application entry point, named windows, routes, history, and backend installation.
• facet_appkit — macOS backend.
• facet_uikit — iOS backend.
• facet_android — Android backend.
• facet_gtk — GTK 4 backend for Linux.
• facet_win32 — native Win32 backend.
• flex_layout — shared Flexbox and Grid layout engine.
• inspector — mounted-tree inspection and editing for development.

Agent surface

• agent_core — identities, exposure, capability grants, sensitivity tiers, outcomes, events, and backend interface.
• facet_agent — optional agent integration for Facet applications.
• agent_mcp and agent_inapp — external JSON-RPC/MCP and in-process access.
• agent_appkit, agent_uikit, agent_android, agent_gtk, and agent_win32 — platform tree adapters.
• agent_jwt — token verification for grant policies.

See Agent surface for the shared authorization model.

Native capabilities

• notifications and applinks
• camera, location, and sensors
• biometrics, securestore, and permissions
• filepicker, haptics, and share
• http and fswatch
• terminal — terminal screen model and native widgets on macOS and Linux.

Each package page records its platform coverage and explicit unsupported outcomes.

Platform bindings

• Apple: appkit, uikit, foundation, quartzcore, metal, avfoundation, corelocation, coremotion, coreml, localauthentication, mapkit, and vision.
• Linux/GTK: gtk4, adwaita, gobject, and their GLib/GIO/Cairo/Pango support packages.
• Windows: win32.
• Android: android_view and jni.
• Embedded: espidf.

Numerics, GPU, and AI

• simd, cblas, and accelerate
• metal and cuda
• llama_cpp and coreai

Real-time

• rt — fixed pools, rings, and other primitives used with the compiler's real-time contracts.
• rt_darwin — Darwin-specific real-time support.