[Build]: Automated build for testing no threads (#641) doesn't do the job well

[VzdornovNA88]

So, as promised, I started playing with this PR (#641 ) and immediately discovered several problems that I hadn't seen when the PR was under review.

Problems :

1. My suggestion was to use include(CheckIncludeFileCXX) to check support for the standard threading model, but I didn't take into account that some toolchains actually provide sources, it's just that support for a specific function is blocked at the preprocessor level (for example, gcc 10.2.1, I don't think anything will change in the future while clang does not provide such sources for arm), as for the unification of the building for different toolchains, this method is not correct and does not do the right job, I want to note here , what I don't pass on when building '-DCAN_STACK_DISABLE_THREADS=ON"' is actually what the source check was supposed to do, which was actually supposed to be named as "checking support for the standard C++ threading model".

2. And one more thing (I don't know if this is a problem), based on the semantics of what was done, that is, stubs for standard library files were added, in them we detect a compilation error using the preprocessor and say that we prohibit the inclusion of sources that relate to the threading model if it is disabled in the library and then #include was added to all the resulting targets, but at the same time, the paths to the stubs were not taken into account in the cmake files of such targets, and they were taken into account for the isobus library itself, but not for the examples.This leads to the fact that we do not get the desired error at the beginning of a long list of errors when trying to build such an example.

Environment and build command :

I work in vscode, so here I will provide the output data and user arguments for cmake : (The toolchain file for arm none eabi toolchains is used below, which you can find in #647 )

Ubuntu 20.04

[build] /usr/bin/stm32-gcc-cmake-tool-chain/eabi/bin/arm-none-eabi-g++ --sysroot=/usr/bin/stm32-gcc-cmake-tool-chain/eabi/bin/../arm-none-eabi -DCAN_PORT_MAXIMUM_VALUE=4 -DCAN_STACK_DISABLE_THREADS -DISOBUS_UNKNOWN_AVAILABLE -I../examples/diagnostic_protocol -I../isobus/include -I../hardware_integration/include -I../utility/include -specs=nosys.specs -mcpu=cortex-m7 -march=armv7e-m -mfpu=neon -mfloat-abi=hard -mthumb -ffunction-sections -fdata-sections -fno-rtti -fno-exceptions -fno-threadsafe-statics -g3 -O2 -DNDEBUG -Wall -Wextra -MD -MT examples/diagnostic_protocol/CMakeFiles/DiagnosticProtocolExample.dir/main.cpp.obj -MF examples/diagnostic_protocol/CMakeFiles/DiagnosticProtocolExample.dir/main.cpp.obj.d -o examples/diagnostic_protocol/CMakeFiles/DiagnosticProtocolExample.dir/main.cpp.obj -c ../examples/diagnostic_protocol/main.cpp [build] In file included from ../examples/diagnostic_protocol/main.cpp:10:

{
"cmake.configureArgs": [
"-DCMAKE_TOOLCHAIN_FILE=/home/vzdornovna/yocto_work/current_projects/AgIsoStack-plus-plus/cmake/arm-none-eabi.cmake",
"-DARM_TOOLCHAIN_PATH=/home/vzdornovna/yocto_work/current_projects/toolchains/arm-none-eabi/LLVMEmbeddedToolchainForArm-13.0.0",
"-DARM_CPU_ARCH=cortex-m7-neon",
// "-DCAN_STACK_DISABLE_THREADS=ON"
"-DBUILD_EXAMPLES=ON"
// "-DBUILD_TESTING=ON"
],
}

to repeat, you can just take #647 for yourself, previously it took care of disabling the threading model itself, but now that we are seriously fixing this feature in main, I disabled this functionality in #647 and now it is completely consistent with the behavior of main.

[GwnDaan]

2. And one more thing (I don't know if this is a problem), based on the semantics of what was done, that is, stubs for standard library files were added, in them we detect a compilation error using the preprocessor and say that we prohibit the inclusion of sources that relate to the threading model if it is disabled in the library and then #include was added to all the resulting targets, but at the same time, the paths to the stubs were not taken into account in the cmake files of such targets, and they were taken into account for the isobus library itself, but not for the examples.This leads to the fact that we do not get the desired error at the beginning of a long list of errors when trying to build such an example.

This is by design. All the examples are multithreaded. So we naturally don't want the checks to be done on the examples

[VzdornovNA88]

I'm going to change seeder_example to single-threaded and multi-threaded, it's not difficult.

This for my understanding...

Of course it is not important but
then I have a question about the examples, they can all be built from even with the thread model disabled, but only one of them is not at the cmake level(in main now), which is why I decided that your adding the #include was intended for such a check, although if they all involve working with threads,The restriction then had to be extended to all examples at the cmake level, and this was done initially in my local branch.

[GwnDaan]

I'm going to change seeder_example to single-threaded and multi-threaded, it's not difficult.

It's not about being difficult, it's that the examples become more and more complex and difficult to read for beginners. Sure you can forcefully deny allowing -DBUILD_EXAMPLES but it limits flexibility for users that want to quickly prototype with the examples by modifying them to their needs.

Instead I would recommend to just raise a CMake warning with an explanation when both BUILD_EXAMPLES and CAN_STACK_THREADS_DISABLED is set.

[VzdornovNA88]

After the fix with your recomendations data output from cmake and gcc 10 arm-none-eabi (I am giving the data output just to show how I am testing and what I expect to see): the test was performed on #647 + this PR

/usr/bin/cmake -DCMAKE_BUILD_TYPE:STRING=RelWithDebInfo -DCMAKE_EXPORT_COMPILE_COMMANDS:BOOL=TRUE -DCMAKE_C_COMPILER:FILEPATH=/usr/bin/stm32-gcc-cmake-tool-chain/eabi/bin/arm-none-eabi-gcc -DCMAKE_CXX_COMPILER:FILEPATH=/usr/bin/stm32-gcc-cmake-tool-chain/eabi/bin/arm-none-eabi-g++ -DCMAKE_TOOLCHAIN_FILE=/home/vzdornovna/yocto_work/current_projects/AgIsoStack-plus-plus/cmake/arm-none-eabi.cmake -DARM_TOOLCHAIN_PATH=/home/vzdornovna/yocto_work/current_projects/toolchains/arm-none-eabi/LLVMEmbeddedToolchainForArm-13.0.0 -DARM_CPU_ARCH=cortex-m7-neon -DBUILD_EXAMPLES=ON --no-warn-unused-cli -S /home/vzdornovna/yocto_work/current_projects/AgIsoStack-plus-plus -B /home/vzdornovna/yocto_work/current_projects/AgIsoStack-plus-plus/build -G Ninja

[cmake] -- Using pre-defined C compiler: /usr/bin/stm32-gcc-cmake-tool-chain/eabi/bin/arm-none-eabi-gcc
[cmake] -- Using pre-defined C++ compiler: /usr/bin/stm32-gcc-cmake-tool-chain/eabi/bin/arm-none-eabi-g++

[cmake] -- Compiler info: arm-none-eabi-gcc (xPack GNU Arm Embedded GCC, 64-bit) 10.2.1 20201103 (release)

[cmake] -- Compiler detected: GCC
[cmake] -- Using sysroot from pre-installed GCC compiler: /usr/bin/stm32-gcc-cmake-tool-chain/eabi/bin/../arm-none-eabi
[cmake] -- ========================================
[cmake] -- ARM none EABI toolchain configuration
[cmake] -- ========================================
[cmake] -- C compiler: /usr/bin/stm32-gcc-cmake-tool-chain/eabi/bin/arm-none-eabi-gcc
[cmake] -- C++ compiler: /usr/bin/stm32-gcc-cmake-tool-chain/eabi/bin/arm-none-eabi-g++
[cmake] -- Compiler type: GCC
[cmake] -- Target triple: arm-none-eabi
[cmake] -- CPU architecture: cortex-m7-neon
[cmake] -- CPU: cortex-m7
[cmake] -- Architecture: armv7e-m
[cmake] -- FPU: neon
[cmake] -- Float ABI: hard
[cmake] -- Common flags: -specs=nosys.specs -mcpu=cortex-m7 -march=armv7e-m -mfpu=neon -mfloat-abi=hard -mthumb -ffunction-sections -fdata-sections -fno-rtti -fno-exceptions -fno-threadsafe-statics

[cmake] -- ARM_NONE_EABI_PLATFORM: TRUE (set by toolchain)

[cmake] -- ========================================

[cmake] -- The CXX compiler identification is GNU 10.2.1
[cmake] -- Check for working CXX compiler: /usr/bin/stm32-gcc-cmake-tool-chain/eabi/bin/arm-none-eabi-g++
[cmake] -- Check for working CXX compiler: /usr/bin/stm32-gcc-cmake-tool-chain/eabi/bin/arm-none-eabi-g++ -- works
[cmake] -- Detecting CXX compiler ABI info
[cmake] -- Detecting CXX compiler ABI info - done
[cmake] -- Detecting CXX compile features
[cmake] -- Detecting CXX compile features - done

[cmake] CMake Warning at CMakeLists.txt:43 (message):
[cmake] C++ threading model is not supported. Setting CAN_STACK_DISABLE_THREADS to
[cmake] ON.
[cmake]
[cmake]
[cmake] CMake Warning (dev) at hardware_integration/CMakeLists.txt:18 (message):
[cmake] No CAN driver specified, choosing UNKNOWN by default. Set the CAN_DRIVER
[cmake] variable with -DCAN_DRIVER= to specify another driver. or
[cmake] -DCAN_DRIVER=";" to specify multiple drivers.
[cmake] This warning is for project developers. Use -Wno-dev to suppress it.
[cmake]
[cmake] CMake Warning at CMakeLists.txt:105 (message):
[cmake] You are trying to build examples while the isobus library is configured in
[cmake] single-threaded mode, examples cannot be built in this mode. The current
[cmake] build configuration is (BUILD_EXAMPLES == ON AND CAN_STACK_DISABLE_THREADS
[cmake] == ON), please change the configuration.
[cmake]
[cmake]
[cmake] -- Disabled built-in multi-threading for CAN stack.
[cmake] -- The C compiler identification is GNU 10.2.1