menu "C/C++ and POSIX layer" config RT_USING_INTERNAL_LIBC_ONLY bool "Only use tool chain internal libc" default n help This option is for RT-Thread Nano version. If select this option, it will not compile components/libc folder and only use tool chain internal libc. Normally, the tool chain internal is only cover ISO standard (e.g. armcc), but some tool chains' internal libc will cover more than ISO standard (e.g. newlib). However, no matter the cover level it is, the rt-thread libc leveling layer will not be involved at all if select this option. config RT_USING_EXTERNAL_LIBC depends on !RT_USING_INTERNAL_LIBC_ONLY bool help This is for external libc(e.g. mlib), and NOT for newlib or picolibc which are inherent in the toolchains. Usually, the external libc should be a software package and select RT_USING_EXTERNAL_LIBC in software package's Kconfig This option is not available for users to select. source "$RTT_DIR/components/libc/compilers/common/Kconfig" source "$RTT_DIR/components/libc/posix/Kconfig" source "$RTT_DIR/components/libc/cplusplus/Kconfig" endmenu