oveRTOS C API Reference

oveRTOS is an embedded RTOS framework that provides a unified build system, configuration, and portable C API across FreeRTOS, Apache NuttX, Zephyr RTOS, and POSIX. This reference documents the C API. The correct backend implementation is selected at compile time via Kconfig preprocessor symbols, with no virtual dispatch and minimal runtime overhead over the native API.

Include every module at once with the umbrella header:

#include <ove/ove.h>

API Modules

Core kernel primitives

Module	Header	Description
Types	ove/types.h	Common types and error codes
Application lifecycle	ove/app.h	Application entry point and scheduler start
Thread management	ove/thread.h	Thread lifecycle, sleep, yield, priority
Synchronisation primitives	ove/sync.h	Mutexes, semaphores, events, condition variables
Message queue	ove/queue.h	Fixed-size item FIFO message queues
Software timer	ove/timer.h	Software timers
Event Group	ove/eventgroup.h	Multi-bit event flags
Work Queue	ove/workqueue.h	Deferred work on a dedicated thread
Stream	ove/stream.h	Byte-stream ring buffers
Time	ove/time.h	Monotonic clock and delays

Board, hardware I/O, and bus drivers

Module	Header	Description
Board Initialization	ove/board.h	Board initialisation and identification
Board Type Definitions	ove/board_types.h	Board descriptor and LED descriptor struct definitions
GPIO	ove/gpio.h	General-purpose I/O
LED	ove/led.h	On-board LED control
Watchdog	ove/watchdog.h	Hardware watchdog timer
Console	ove/console.h	Serial console I/O
UART	ove/uart.h	UART serial bus driver
SPI	ove/spi.h	SPI master bus driver
I2C	ove/i2c.h	I2C master bus driver
I2S	ove/i2s.h	I2S / SAI audio bus driver with DMA double buffering

Storage, filesystem, and NVS

Module	Header	Description
File System	ove/fs.h	Filesystem abstraction (VFS)
Non-Volatile Storage	ove/nvs.h	Non-volatile key-value storage

Audio and ML

Module	Header	Description
Audio graph engine	ove/audio.h	Audio graph engine (sources, processors, sinks)
Audio node types and built-in factories	ove/audio_node.h	Node types, vtable, and built-in processing nodes
Audio device node factories	ove/audio_device.h	Transport abstraction and device node factories
ML Inference	ove/infer.h	ML inference engine (LiteRT / TensorFlow Lite Micro)

Networking

Module	Header	Description
Networking	ove/net.h	BSD-like sockets, DNS, network interface
TLS	ove/net_tls.h	TLS sessions over TCP (mbedTLS)
HTTP Client	ove/net_http.h	HTTP/1.1 client
MQTT Client	ove/net_mqtt.h	MQTT 3.1.1 client
HTTP Server	ove/net_httpd.h	Embedded HTTP server with routing and WebSocket
SNTP Client	ove/net_sntp.h	Simple NTP time synchronisation

Power management

Module	Header	Description
Power Management	ove/pm.h	Sleep states, wake sources, power domains, statistics

User interface and diagnostics

Module	Header	Description
Shell	ove/shell.h	Interactive command shell
Logging	ove/log.h	Compile-time filtered logging macros
LVGL Display Integration	ove/lvgl.h	Unified LVGL display include
LVGL Internal Helpers	ove/lvgl_internal.h	LVGL display integration hooks

Framework internals

Module	Header	Description
oveRTOS Umbrella Header	ove/ove.h	Umbrella header that pulls in every subsystem
Storage Types	ove/storage.h	Backend-specific opaque storage types
OVE_*_DEFINE Macros	ove/storage.h	OVE_*_DEFINE() instance macros
OVE_*_DEFINE_STATIC Macros	ove/storage.h	OVE_*_DEFINE_STATIC() file-scope declarations
Heap Gates	ove/storage.h	OVE_HEAP_* gates selecting heap vs. zero-heap bodies
BSP Compatibility Shim	ove/bsp.h	Legacy BSP compatibility shim

Allocation Strategies

Every object-bearing module supports two allocation modes:

• Heap mode (default) – _create() / _destroy() with dynamic allocation.
• Zero-heap mode (CONFIG_OVE_ZERO_HEAP) – _init() / _deinit() with caller-supplied static buffers. The OVE_*_DEFINE_STATIC() macros combine storage declaration and init into a single file-scope declaration.

Further Documentation

For setup, build, configuration, and example walkthroughs, see the oveRTOS documentation site.