FreeRTOS

Setup

Platform/FreeRtos/ wraps FreeRTOS kernel primitives (FreeRTOS documentation). Networking comes from a separate platform; the platform × capability matrix shows which fill it.

Fills the Mutex role, plus a sysUpTime callback.

What it ships

Header	What it is
SolidSyslogFreeRtosMutex.h	A Mutex wrapping a statically-allocated FreeRTOS mutex semaphore, for thread-safe buffers and pools on a FreeRTOS target.
SolidSyslogFreeRtosMutexErrors.h	Source identity for the FreeRtosMutex adapter; the detail codes it reports are the portable ones in SolidSyslogMutexErrors.h.
SolidSyslogFreeRtosSysUpTime.h	The FreeRTOS SolidSyslogSysUpTimeFunction, for the MetaSd structured-data element.

Requirements

configSUPPORT_STATIC_ALLOCATION=1 - the mutex uses static allocation.

FreeRTOS kernel V10.6.0 or later. The uptime callback selects its implementation on configTICK_TYPE_WIDTH_IN_BITS, which that release introduced. An older kernel defines neither it nor the TICK_TYPE_WIDTH_* constants, and the preprocessor reads an undefined name as zero, so both implementations compile in and the link fails on the duplicate definition. The pack is tested against V11.1.0.

Security behaviour and obligations

The mutex guards a buffer shared between tasks

The circular buffer uses it when the task calling Log is not the task calling Service. Where both run on one task, the Null mutex is the correct choice and costs nothing.

Static allocation is required, and is the point

configSUPPORT_STATIC_ALLOCATION=1 is not a convenience: the kernel object is created from storage inside the library's own pool, so the adapter allocates nothing at run time and cannot fail for want of heap.

Uptime is a tick count, not a clock

The sysUpTime callback reports kernel ticks since boot. It is not wall-clock time and carries no timezone or synchronisation quality - the clock callback is a separate injection point.

SolidSyslogFreeRtos_GetSysUpTime meets the sysUpTime contract on a 32- or 64-bit TickType_t, wrapping at about 497 days as RFC 3418 requires. A 16-bit one resolves to no implementation and will not link; supply your own SolidSyslogSysUpTimeFunction there.

The wraps are counted on a 32-bit counter, because above 100 Hz it reaches its own wrap first - ten times sooner at 1000 Hz. That costs two things. The callback must be reached once per wrap, roughly 50 days at 1000 Hz, which formatting any message does. And it takes a short critical section, so it is safe from any task but not from an interrupt.