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Architecture Overview

A typed binding (C, C++, Rust, or Zig) sits on top of a portable C API that resolves to the selected RTOS at compile time — CONFIG_OVE_RTOS_FREERTOS / ..._NUTTX / ..._ZEPHYR / ..._POSIX picks the backend, the preprocessor selects the corresponding source tree, and the compiler sees exactly one implementation per function. No vtables, no runtime branch on the backend identity.

flowchart TD
    A["<b>Application Code</b><br>C · C++ · Rust · Zig"]
    B["<b>oveRTOS API Layer</b><br>thread · sync · queue · timer · audio · fs · lvgl …"]
    C["<b>CONFIG_OVE_RTOS_*</b><br>compile-time dispatch via Kconfig"]

    A --> B --> C

    C --> D & E & F & G

    subgraph backends [" "]
        direction LR
        D["FreeRTOS<br>backend"] --> H["FreeRTOS<br>kernel"]
        E["NuttX<br>backend"] --> I["NuttX<br>kernel"]
        F["Zephyr<br>backend"] --> J["Zephyr<br>kernel"]
        G["POSIX<br>backend"] --> K["pthreads<br>sim"]
    end

    style A fill:#5c6bc0,stroke:#3949ab,color:#fff
    style B fill:#1e88e5,stroke:#1565c0,color:#fff
    style C fill:#f57c00,stroke:#e65100,color:#fff
    style D fill:#43a047,stroke:#2e7d32,color:#fff
    style E fill:#43a047,stroke:#2e7d32,color:#fff
    style F fill:#43a047,stroke:#2e7d32,color:#fff
    style G fill:#43a047,stroke:#2e7d32,color:#fff
    style H fill:#546e7a,stroke:#37474f,color:#fff
    style I fill:#546e7a,stroke:#37474f,color:#fff
    style J fill:#546e7a,stroke:#37474f,color:#fff
    style K fill:#546e7a,stroke:#37474f,color:#fff
    style backends fill:none,stroke:none

Two allocation modes

Every primitive has a heap-mode constructor (_create() / _destroy()) and a static-storage constructor (_init() / _deinit() with caller-owned ove_*_storage_t, or the OVE_*_DEFINE_STATIC one-step macro).

Constructor Heap mode (default) Zero-heap (CONFIG_OVE_ZERO_HEAP=y)
_create() / _destroy() Allocate / free from RTOS heap Symbol not declared — calling is a link error
_init() / _deinit() Caller-supplied storage Caller-supplied storage
OVE_*_DEFINE_STATIC() File-scope static + auto-init Same — portable across both modes

Apps that need both modes pick OVE_*_DEFINE_STATIC because that macro alone compiles identically in either configuration. The link-error in zero-heap mode is intentional — no silent fallback.

See also