I could of course be lazy and determine it by path alone. But say I want a more reliable approach, like:

if(IS_AVR)
   add_compile_options(
        --arduino-avr-specific-option
    )
endif()

CMake does not support this natively, like it does with detecting windows/ios/linux. What I am doing currently is the inverse approach:

# If CMAKE_AVR_ROOT is set, I assume we compile for arduino/atmel and set the flags accordingly
if(CMAKE_AVR_ROOT)
    set(CMAKE_SYSTEM_NAME  Generic)
    # another problem with this approach is you get .exe on windows, but not linux
    # so this won't work on linux without an additional IF
    set(CMAKE_C_COMPILER ${CMAKE_AVR_BIN}/avr-gcc.exe)
    set(CMAKE_CXX_COMPILER ${CMAKE_AVR_BIN}/avr-g++.exe)
endif()

I would prefer if the CMake was set up to detect avr-gcc.exe somehow from CMAKE_C_COMPILER. Then, I'd set IS_AVR and all my conditional flags/includes would be under if(IS_AVR). This would make the CMake work with other tools that set compiler automatically.

What is an elegant way of detecting AVR target of compilation by compiler alone?

I could of course be lazy and determine it by path alone. But say I want a more reliable approach, like:

if(IS_AVR)
   add_compile_options(
        --arduino-avr-specific-option
    )
endif()

CMake does not support this natively, like it does with detecting windows/ios/linux. What I am doing currently is the inverse approach:

# If CMAKE_AVR_ROOT is set, I assume we compile for arduino/atmel and set the flags accordingly
if(CMAKE_AVR_ROOT)
    set(CMAKE_SYSTEM_NAME  Generic)
    # another problem with this approach is you get .exe on windows, but not linux
    # so this won't work on linux without an additional IF
    set(CMAKE_C_COMPILER ${CMAKE_AVR_BIN}/avr-gcc.exe)
    set(CMAKE_CXX_COMPILER ${CMAKE_AVR_BIN}/avr-g++.exe)
endif()

I would prefer if the CMake was set up to detect avr-gcc.exe somehow from CMAKE_C_COMPILER. Then, I'd set IS_AVR and all my conditional flags/includes would be under if(IS_AVR). This would make the CMake work with other tools that set compiler automatically.

What is an elegant way of detecting AVR target of compilation by compiler alone?

• c++
• cmake
• arduino
• avr-gcc

• Would cmake's find_* commands help? What about find_program avr-gcc? – Craig Estey Commented Mar 29 at 2:17
• @CraigEstey I edited the question. What I really want is to detect that user set compiler to the avr compiler. If they did, I enable all arduino specific behavior. And in future, I'd then also throw cmake errors if arduino specific configs are mising. – Tomáš Zato Commented Mar 29 at 9:45
• Hmm ... Still not totally sure what your needs/desires are. So, I'll just take another guess [partly because I'm not super familiar with cmake). If user does env CMAKE_C_COMPILER=avr-gcc cmake .... Or, in the file: find_program(CMAKE_C_COMPILER NAMES gcc clang cc), you want to know if CMAKE_C_COMPILER contains avr-gcc in some form? That would be a string operation? string(FIND ${CMAKE_C_COMPILER} avr-gcc IS_AVR_CC), string(LENGTH ${IS_AVR_CC} IS_AVR (Or, using the REGEX subcommand). – Craig Estey Commented Mar 30 at 0:13

1 Answer 1

You can use check_c_compiler_flag.

For example:

check_c_compiler_flag(-mmcu=atmega328p IS_AVR_COMPILER)
if(NOT IS_AVR_COMPILER)
    message(FATAL_ERROR "Detected non avr gcc")
endif()

https://cmake./cmake/help/latest/module/CheckCCompilerFlag.html