esp-idf/components/rt/idf_changes.md

ESP-IDF Changes

This document is used to track all changes made to the FreeRTOS-Plus-POSIX V1.0.0 source code used in ESP-IDF.

License Headers

• Added SPDX-FileCopyrightText and SPDX-FileContributor tags to all files to pass ESP-IDF pre-commit checks.

POSIX errno

Instead of relying on the FreeRTOS errno scheme by enabling configUSE_POSIX_ERRNO, the errno provided by newlib is used. configUSE_POSIX_ERRNO should stay disabled.

API Changes

mq_open() has been changed to make the arguments mode and attr optional, as specified by POSIX.

The following functions are stubs and always return ENOSYS:

• mq_notify()
• mq_setattr()

Header File Organization

In the original FreeRTOS-Plus-POSIX project, the POSIX header files are provided in the sub directory FreeRTOS-Plus-POSIX. In ESP-IDF, however, the POSIX header files do not need any prefix. This increases compatibility with applications originally written for other platforms. All files originating from the FreeRTOS-Plus-POSIX project have been modified to reflect the different include path.

Wherever possible, ESP-IDF is using header files from newlib instead of the header files from FreeRTOS-Plus-POSIX.

In some cases, additional includes have been added to files from FreeRTOS-Plus-POSIX to simplify building.

Critical Sections

The critical sections have been changed according to the ESP-IDF critical section API.

Definitions

The following definitions have been added to the private include utils.h:

MICROSECONDS_PER_SECOND
NANOSECONDS_PER_SECOND 
NANOSECONDS_PER_TICK   

In FreeRTOS-Plus-POSIX, they are located in the custom time.h, but ESP-IDF uses newlib's time.h, where these definitions are not present.

Code Format

• Files have been formatted by uncrustify, using FreeRTOS' uncrustify.cfc.