Backward Compatibility Of Kconfig Options; Configuration Options Reference - Espressif ESP32-S2 Programming Manual

Chapter 2. API Reference
example, indentations will be corrected if there isn't some misleading previous formatting but it cannot come up
with a common prefix for options inside a menu.
2.8.5 Backward Compatibility of Kconfig Options
The standard Kconfig tools ignore unknown options in sdkconfig. So if a developer has custom settings for
options which are renamed in newer ESP-IDF releases then the given setting for the option would be silently ignored.
Therefore, several features have been adopted to avoid this:
1. confgen.py is used by the tool chain to pre-process sdkconfig files before anything else, for example
menuconfig, would read them. As the consequence, the settings for old options will be kept and not ignored.
2. confgen.py recursively finds all sdkconfig.rename files in ESP-IDF directory which contain old and
new Kconfig option names. Old options are replaced by new ones in the sdkconfig file.
3. confgen.py post-processes sdkconfig files and generates all build outputs (sdkconfig.h, sdkcon-
fig.cmake, auto.conf) by adding a list of compatibility statements, i.e. value of the old option is set
the value of the new option (after modification). This is done in order to not break customer codes where old
option might still be used.
4. Deprecated options and their replacements
2.8.6 Configuration Options Reference
Subsequent sections contain the list of available ESP-IDF options, automatically generated from Kconfig files. Note
that depending on the options selected, some options listed here may not be visible by default in the interface of
menuconfig.
By convention, all option names are upper case with underscores. When Kconfig generates sdkconfig and sdkconfig.h
files, option names are prefixed with CONFIG_. So if an option ENABLE_FOO is defined in a Kconfig file and
selected in menuconfig, then sdkconfig and sdkconfig.h files will have CONFIG_ENABLE_FOO defined. In this
reference, option names are also prefixed with CONFIG_, same as in the source code.
SDK tool configuration
Contains:
• CONFIG_SDK_MAKE_WARN_UNDEFINED_VARIABLES
• CONFIG_SDK_TOOLPREFIX
• CONFIG_SDK_PYTHON
• CONFIG_SDK_TOOLCHAIN_SUPPORTS_TIME_WIDE_64_BITS
CONFIG_SDK_TOOLPREFIX
Compiler toolchain path/prefix
Found in: SDK tool configuration
The prefix/path that is used to call the toolchain. The default setting assumes a crosstool-ng gcc setup
that is in your PATH.
Default value:
•"xtensa-esp32s2-elf-"
CONFIG_SDK_PYTHON
Python interpreter
Found in: SDK tool configuration
The executable name/path that is used to run python.
(Note: This option is used with the legacy GNU Make build system only.)
Espressif Systems
are automatically generated by confgen.py.
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