From 1daa2d54e31bfd6e57509991f23ab52fa8bc0801 Mon Sep 17 00:00:00 2001 From: Philippe Leduc Date: Wed, 3 Sep 2025 09:50:12 +0200 Subject: [PATCH] Documentation/guides: Update CMake C++ guide Use the exported CMake toolchain file instead of a custom and broken one. Slightly modify the C++ example code to introduce modern tools like auto keyword and shared_ptr Signed-off-by: Philippe Leduc --- Documentation/guides/cpp_cmake.rst | 225 +++++++++-------------------- 1 file changed, 69 insertions(+), 156 deletions(-) diff --git a/Documentation/guides/cpp_cmake.rst b/Documentation/guides/cpp_cmake.rst index 71948e73008..925a73faeb9 100644 --- a/Documentation/guides/cpp_cmake.rst +++ b/Documentation/guides/cpp_cmake.rst @@ -29,18 +29,27 @@ Preparation #. Base NuttX compilation changes - For this example, load the configuration 'stm32f4discovery:testlibcxx' for building + For this example, load the configuration 'stm32f4discovery:nsh' for building (Linux host) .. code-block:: console $ cd nuttx - $ ./tools/configure.sh stm32f4discovery:testlibcxx + $ ./tools/configure.sh -l stm32f4discovery:nsh + + See :ref:`quickstart/compiling_make:Initialize Configuration` for more information about configure.sh tool. In menuconfig, the main points to be changed on a typical NuttX configuration are the following: - * Set RTOS Features -> Tasks and Scheduling -> Application entry point to 'hellocpp_main' + * RTOS Features -> Tasks and Scheduling -> Application entry point to 'main' + * Library Routines -> Have C++ compiler + * Library Routines -> Have C++ initialization -> C++ Library -> Toolchain C++ support (you can also choose the basic version or the LLVM one) + * Library Routines -> Have C++ initialization -> C++ Library -> C++ low level library select -> GNU low level libsupc++ + * Library Routines -> Language standard -> choose the version you want - for this example we will use "c++17" + * Library Routines -> Enable Exception Support -> to enable to support C++ exceptions - for this example we will select it + * Library Routines -> Enable RTTI Support -> to enable to support C++ RTTI features (like dynamic_cast()/typeid()) - for this example we will not enable it - * Build NuttX and generate the export + + Build NuttX and generate the export .. code-block:: console @@ -57,14 +66,12 @@ Creating the project hellocpp/ hellocpp/CMakeLists.txt - hellocpp/cmake/stm32f4discovery.cmake - hellocpp/nuttx-export-10.0.1/ - hellocpp/src/CMakeLists.txt - hellocpp/src/main.cpp - hellocpp/src/HelloWorld.h - hellocpp/src/HelloWorld.cpp + hellocpp/nuttx-export-12.10.0/ + hellocpp/main.cpp + hellocpp/HelloWorld.h + hellocpp/HelloWorld.cpp - The directory 'nuttx-export-10.0.1' is the unzipped content from the file created during + The directory 'nuttx-export-12.10.0' is the unzipped content from the file created during make export procedure done before. #. File contents @@ -73,7 +80,7 @@ Creating the project .. code-block:: cmake - cmake_minimum_required(VERSION 3.2...3.15) + cmake_minimum_required(VERSION 3.12...3.31) project(HelloCpp VERSION 1.0 @@ -82,159 +89,63 @@ Creating the project set(CMAKE_CXX_STANDARD 17) set(CMAKE_CXX_STANDARD_REQUIRED ON) - # set(CMAKE_CXX_EXTENSIONS OFF) - set(CMAKE_C_STANDARD 99) - - set(NUTTX_PATH "${CMAKE_SOURCE_DIR}/nuttx-export-10.0.1") - - include(cmake/stm32f4discovery.cmake) - - set(AC_COMMON_FLAGS "${AC_COMMON_FLAGS} -Wall -Wshadow -Wundef -fno-strict-aliasing -Os") - set(AC_COMMON_FLAGS "${AC_COMMON_FLAGS} -D_DEBUG -D_LIBCPP_BUILD_STATIC -D_LIBCPP_NO_EXCEPTIONS ") - set(AC_COMMON_FLAGS "${AC_COMMON_FLAGS} -fno-exceptions -fcheck-new -fno-rtti -pedantic ") - set(AC_COMMON_FLAGS "${AC_COMMON_FLAGS} -nostdinc++") - - set(AC_DEFINES "${AC_DEFINES} -DCONFIG_WCHAR_BUILTIN") - - include_directories( - src - ${NUTTX_PATH}/include - ${NUTTX_PATH}/include/libcxx - ${NUTTX_PATH}/arch/chip - ) - - set(EXE_NAME hellocpp) - set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${AC_HW_FLAGS} ${AC_DEFINES}") - set(CMAKE_CXX_FLAGS "${AC_HW_FLAGS} ${AC_DEFINES} ${AC_COMMON_FLAGS} ${AC_CXX_EXTRA_FLAGS}") - if (PARAM_DEBUG) - set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -g") - endif() - - set(CMAKE_SKIP_RPATH ON) - set(CMAKE_CXX_LINK_EXECUTABLE "${CMAKE_LINKER} ${AC_LINKER_FLAGS} -o ${EXE_NAME}.elf ") - set(BUILD_SHARED_LIBS OFF) - add_subdirectory(src) - -* hellocpp/cmake/stm32f4discovery.cmake - -.. code-block:: cmake - - set(CMAKE_SYSTEM_NAME Generic) - set(CMAKE_SYSTEM_PROCESSOR arm) - - set(MCU_LINKER_SCRIPT "${NUTTX_PATH}/scripts/ld.script") - - set(COMPILER_PREFIX arm-none-eabi-) - - # cmake-format: off - set(CMAKE_C_COMPILER ${COMPILER_PREFIX}gcc) - set(CMAKE_CXX_COMPILER ${COMPILER_PREFIX}g++) - set(CMAKE_AR ${COMPILER_PREFIX}ar) - set(CMAKE_RANLIB ${COMPILER_PREFIX}ranlib) - set(CMAKE_LINKER ${COMPILER_PREFIX}ld) - set(CMAKE_ASM_COMPILER ${COMPILER_PREFIX}gcc) - set(CMAKE_OBJCOPY ${COMPILER_PREFIX}objcopy) - set(CMAKE_OBJDUMP ${COMPILER_PREFIX}objdump) - set(CMAKE_SIZE ${COMPILER_PREFIX}size) - - set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER) - set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY) - set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY) - set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY) - - set(CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY) - - set(AC_HW_FLAGS "-mcpu=cortex-m4 -mthumb -mfloat-abi=soft ") - set(AC_HW_FLAGS "${AC_HW_FLAGS} -isystem ${NUTTX_PATH}/include") - set(AC_HW_FLAGS "${AC_HW_FLAGS} -pipe") - - set(AC_LINKER_FLAGS "--entry=__start -nostdlib -T${MCU_LINKER_SCRIPT}") - -* hellocpp/src/CMakeLists.txt - -.. code-block:: cmake - - set(HEADER_FILES - HelloWorld.h - ) set(SOURCE_FILES - HelloWorld.cpp + ${CMAKE_CURRENT_SOURCE_DIR}/HelloWorld.cpp + ${CMAKE_CURRENT_SOURCE_DIR}/main.cpp ) - link_directories(${EXE_NAME} ${NUTTX_PATH}/libs) - - add_executable(${EXE_NAME} ${SOURCE_FILES} main.cpp ${HEADER_FILES}) + set(EXE_NAME "hello") + add_executable(${EXE_NAME} ${SOURCE_FILES}) add_custom_command( TARGET ${EXE_NAME} POST_BUILD - COMMAND ${CMAKE_OBJCOPY} ARGS -S -O binary ${CMAKE_BINARY_DIR}/${EXE_NAME}.elf ${CMAKE_BINARY_DIR}/${EXE_NAME}.bin - ) + COMMAND ${CMAKE_OBJCOPY} ARGS -S -O binary ${CMAKE_BINARY_DIR}/${EXE_NAME} ${CMAKE_BINARY_DIR}/${EXE_NAME}.bin - target_link_libraries(${EXE_NAME} --start-group) - target_link_libraries(${EXE_NAME} sched) - target_link_libraries(${EXE_NAME} drivers) - target_link_libraries(${EXE_NAME} boards) - target_link_libraries(${EXE_NAME} c) - target_link_libraries(${EXE_NAME} mm) - target_link_libraries(${EXE_NAME} arch) - target_link_libraries(${EXE_NAME} xx) - target_link_libraries(${EXE_NAME} apps) - target_link_libraries(${EXE_NAME} fs) - target_link_libraries(${EXE_NAME} binfmt) - target_link_libraries(${EXE_NAME} board) - target_link_libraries(${EXE_NAME} gcc) - target_link_libraries(${EXE_NAME} supc++) - - target_link_libraries(${EXE_NAME} --end-group) - -* hellocpp/src/main.cpp +* hellocpp/main.cpp .. code-block:: c++ + #include + #include "HelloWorld.h" - #include - extern "C" + extern "C" int main(int, char*[]) { - int hellocpp_main(void) - { + auto pHelloWorld = std::make_shared(); + pHelloWorld->HelloWorld(); - CHelloWorld *pHelloWorld = new CHelloWorld(); - pHelloWorld->HelloWorld(); + CHelloWorld helloWorld; + helloWorld.HelloWorld(); - CHelloWorld helloWorld; - helloWorld.HelloWorld(); - - delete pHelloWorld; - return 0; - } + return 0; } -* hellocpp/src/HelloWorld.h + +* hellocpp/HelloWorld.h .. code-block:: c++ - #ifndef HELLOWORLD_H_ - #define HELLOWORLD_H_ - - #include "nuttx/config.h" + #ifndef HELLOWORLD_H + #define HELLOWORLD_H class CHelloWorld { - public: - CHelloWorld(); - ~CHelloWorld(); - bool HelloWorld(void); - private: - int mSecret; + public: + CHelloWorld(); + ~CHelloWorld() = default; + + bool HelloWorld(); + + private: + int mSecret; }; #endif -* hellocpp/src/HelloWorld.cpp +* hellocpp/HelloWorld.cpp .. code-block:: c++ @@ -243,30 +154,32 @@ Creating the project #include "HelloWorld.h" - CHelloWorld::CHelloWorld() { - mSecret = 42; - std::printf("Constructor: mSecret=%d\n",mSecret); + CHelloWorld::CHelloWorld() + { + mSecret = 42; + std::printf("Constructor: mSecret=%d\n",mSecret); } - CHelloWorld::~CHelloWorld() { + bool CHelloWorld::HelloWorld() + { + std::printf("HelloWorld: mSecret=%d\n",mSecret); + + std::string sentence = "Hello"; + std::printf("TEST=%s\n",sentence.c_str()); + + if (mSecret == 42) + { + std::printf("CHelloWorld: HelloWorld: Hello, world!\n"); + return true; + } + else + { + std::printf("CHelloWorld: HelloWorld: CONSTRUCTION FAILED!\n"); + return false; + } } - bool CHelloWorld::HelloWorld(void) { - std::printf("HelloWorld: mSecret=%d\n",mSecret); - - std::string sentence = "Hello"; - std::printf("TEST=%s\n",sentence.c_str()); - - if (mSecret == 42) { - std::printf("CHelloWorld: HelloWorld: Hello, world!\n"); - return true; - } - else { - std::printf("CHelloWorld: HelloWorld: CONSTRUCTION FAILED!\n"); - return false; - } - } Building ======== @@ -277,7 +190,7 @@ To launch build, you use the cmake procedure: $ mkdir build $ cd build - $ cmake .. + $ cmake .. -DCMAKE_TOOLCHAIN_FILE=../nuttx-export-12.10.0/scripts/toolchain.cmake $ make -And finally a bin file will be created to be loaded on the board. +Two binaries are generated: an elf one - useful for debug purpose - and a binary one to be flashed on the board