Cmake

Zephyr RTOS building blocks   ::   Device Tree Source   ::   Kconfig   ::   cmake   ::   `west` manifest files

2021-08-06

Starting a page for cmake notes here. Links to cmake site:

• https://cmake.org/overview/
• https://cmake.org/examples/ . . . very limited, need other resources

Longer guides:

• https://cmake.org/cmake/help/v3.21/

A Nordic Semi document on `cmake` and its role in the build process of Zephyr based applications:

• https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/zephyr/guides/build/index.html

2021-08-17 - search for cmake / Zephyr means to add sources to a Zephyr based project:

• https://github.com/zephyrproject-rtos/zephyr/blob/main/cmake/extensions.cmake
• https://cmake.org/cmake/help/latest/manual/cmake-buildsystem.7.html

^ To print variables in cmake

Note that the following post has a cool answer which involves a cmake macro to print all variables known to a given cmake invocation or use, and also a more simple answer to print one specific variable:

• https://stackoverflow.com/questions/31343813/displaying-cmake-variables

A modified generic.cmake file, changes address one or more unset variables and solved build error on newest Zephyr work station:

# SPDX-License-Identifier: Apache-2.0

set_ifndef(CC gcc)

## 2022-03-03 - Ted moving this cmake function call beyond locally
##  added variable assignements:
##
## find_program(CMAKE_C_COMPILER ${CROSS_COMPILE}${CC}   PATHS ${TOOLCHAIN_HOME} NO_DEFAULT_PATH)

#
## - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
## 2022-02-08 Reference https://cmake.org/cmake/help/latest/command/message.html
## - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
#
message(NOTICE "*** zztop 1 *** building with user configuration var ZEPHYR_TOOLCHAIN_VARIANT set to '${ZEPHYR_TOOLCHAIN_VARIANT}'")
message(NOTICE "*** zztop 2 *** internal variable CROSS_COMPILE set to '${CROSS_COMPILE}'")
message(NOTICE "*** zztop 3 *** internal variable TOOLCHAIN_HOME set to '${TOOLCHAIN_HOME}'")

## 2022-03-03 THU - Not ***ing sure why we need to set these today:
set(ZEPHYR_TOOLCHAIN_VARIANT gnuarmemb)
set(GNUARMEMB_TOOLCHAIN_PATH /opt/gcc-arm-none-eabi-10.3-2021.10)
set(TOOLCHAIN_HOME /opt/gcc-arm-none-eabi-10.3-2021.10)
## ^^^ These three cmake variable settings not sufficient, trying another based on working but different
##  toolchain on host ind:
set(CROSS_COMPILE /opt/gcc-arm-none-eabi-10.3-2021.10/bin/arm-none-eabi-)
##
## $ ls /opt/gcc-arm-none-eabi-10.3-2021.10/bin/arm-none-eabi-*
##

message(NOTICE "*** zztop 4 *** building with user configuration var ZEPHYR_TOOLCHAIN_VARIANT set to '${ZEPHYR_TOOLCHAIN_VARIANT}'")
message(NOTICE "*** zztop 5 *** internal variable CROSS_COMPILE set to '${CROSS_COMPILE}'")
message(NOTICE "*** zztop 6 *** internal variable TOOLCHAIN_HOME set to '${TOOLCHAIN_HOME}'")


find_program(CMAKE_C_COMPILER ${CROSS_COMPILE}${CC}   PATHS ${TOOLCHAIN_HOME} NO_DEFAULT_PATH)

if(CMAKE_C_COMPILER STREQUAL CMAKE_C_COMPILER-NOTFOUND)
  message(FATAL_ERROR "Zephyr was unable to find the toolchain. Is the environment misconfigured?
User-configuration:
ZEPHYR_TOOLCHAIN_VARIANT: ${ZEPHYR_TOOLCHAIN_VARIANT}
Internal variables:
CROSS_COMPILE: ${CROSS_COMPILE}
TOOLCHAIN_HOME: ${TOOLCHAIN_HOME}
")
endif()

execute_process(
  COMMAND ${CMAKE_C_COMPILER} --version
  RESULT_VARIABLE ret
  OUTPUT_QUIET
  ERROR_QUIET
  )
if(ret)
  message(FATAL_ERROR "Executing the below command failed. Are permissions set correctly?
'${CMAKE_C_COMPILER} --version'
"
    )
endif()

^ To Specify Source Dirs and Library Directories to Linker

• https://cmake.org/cmake/help/latest/command/link_directories.html

^ Install latest version of cmake

• https://askubuntu.com/questions/355565/how-do-i-install-the-latest-version-of-cmake-from-the-command-line

^ Zephyr Threads Tutorial by Maksim Drachov

• https://github.com/maksimdrachov/zephyr-rtos-tutorial/commit/de52c7d5d564e4990f5659f60e24b487ffdd74ae

 

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