warning: implicit declaration of function

[yama789]

Hello, 

I want to use McuBoot so I added  CONFIG_BOOTLOADER_MCUBOOT=y to prj.conf.

So there were a lot of warnings "implicit declaration of function ".

Part of the warning is below.

I think these warnings is happend in ncs/v2.6.0 but I don't know why these happen just by adding CONFIG_BOOTLOADER_MCUBOOT=y .
please tell me why these happen and tell me something how to solve this problem.

Best regards.

[Vidar Berg]

Hello,

The only reason I can find for this error is if CONFIG_CMSIS_DSP is being selected in the MCUBoot build. The default c library included by MCUBoot does not support these math functions, which would explain the linker warnings.

Are you building your project for a custom board (i.e. not building for 'nrf5340dk_nrf5340_cpuapp' or nrf5340dk_nrf5340_cpuapp_ns')? In that case, please double check that the boards files do not enable the CONFIG_CMSIS_DSP symbol by default. You can also check the configuration file "build/mcuboot/zephyr/.config" to confirm whether the symbol is actually enabled or not.

Best regards,

Vidar

[yama789]

Thank you for your reply.

As you say, I use a custom board and CONFG_XXX to enable CMSIS DSP was used in MCUBoot.
I tried to buid without those CONFIG so that warning was not happend.

thank you.