Posted on March 14, 2018 at 22:47hey guys
I have an stm32f4 discovery board and used stm32 cube to generate a SW4STM32 project with freertos.
SW4STM32 is able to convert a c project to c++ project.
I have read about the problem when mixing c and c++ code and i know about the mangling of the c++ compiler.
There are lots of extern C header guards in the header files.
However i'm still getting a linker error
Building target: Cpp_Test.elf
Invoking: MCU G++ Linker
arm-none-eabi-g++ -mcpu=cortex-m4 -mthumb -mfloat-abi=hard -mfpu=fpv4-sp-d16 -specs=nosys.specs -specs=nano.specs -T'../STM32F429ZITx_FLASH.ld' -Wl,-Map=output.map -Wl,--gc-sections -fno-exceptions -fno-rtti -o 'Cpp_Test.elf' @'objects.list' -lm
Src/freertos.o: In function `StartDefaultTask':
xxxx\Cpp_Test\Debug/../Src/freertos.c:131: undefined reference to `calc_values'
collect2.exe: error: ld returned 1 exit status
makefile:59: recipe for target 'Cpp_Test.elf' failed
make: *** [Cpp_Test.elf] Error 1
my test_cpp.h file looks like this
#ifndef USER_TEST_CPLUS_H_
#define USER_TEST_CPLUS_H_
#include 'stdint.h'
int calc_values();
#endif /* USER_TEST_CPLUS_H_ */
my test_cpp.cpp file looks like this
#include 'test_cplus.h'
#include <iostream>
using namespace std;
class Rectangle {
int width, height;
public:
void set_values (int,int);
int area() {return width*height;}
};
void Rectangle::set_values (int x, int y) {
width = x;
height = y;
}
int calc_values()
{
Rectangle rect;
rect.set_values(1,2);
int area = rect.area();
return area;
}
the calc_values() function is called from the freertos default task in freertos.c
/* Includes ------------------------------------------------------------------*/
#include 'FreeRTOS.h'
#include 'task.h'
#include 'cmsis_os.h'
/* USER CODE BEGIN Includes */
#include 'test_file.h'
#include 'test_cplus.h'
/* USER CODE END Includes */
/* Variables -----------------------------------------------------------------*/
osThreadId defaultTaskHandle;
/* USER CODE BEGIN Variables */
/* USER CODE END Variables */
/* Function prototypes -------------------------------------------------------*/
void StartDefaultTask(void const * argument);
extern void MX_USB_DEVICE_Init(void);
extern void MX_FATFS_Init(void);
void MX_FREERTOS_Init(void); /* (MISRA C 2004 rule 8.1) */
/* USER CODE BEGIN FunctionPrototypes */
/* USER CODE END FunctionPrototypes */
/* Hook prototypes */
/* Init FreeRTOS */
void MX_FREERTOS_Init(void) {
/* USER CODE BEGIN Init */
/* USER CODE END Init */
/* USER CODE BEGIN RTOS_MUTEX */
/* add mutexes, ... */
/* USER CODE END RTOS_MUTEX */
/* USER CODE BEGIN RTOS_SEMAPHORES */
/* add semaphores, ... */
/* USER CODE END RTOS_SEMAPHORES */
/* USER CODE BEGIN RTOS_TIMERS */
/* start timers, add new ones, ... */
/* USER CODE END RTOS_TIMERS */
/* Create the thread(s) */
/* definition and creation of defaultTask */
osThreadDef(defaultTask, StartDefaultTask, osPriorityNormal, 0, 128);
defaultTaskHandle = osThreadCreate(osThread(defaultTask), NULL);
/* USER CODE BEGIN RTOS_THREADS */
/* add threads, ... */
/* USER CODE END RTOS_THREADS */
/* USER CODE BEGIN RTOS_QUEUES */
/* add queues, ... */
/* USER CODE END RTOS_QUEUES */
}
/* StartDefaultTask function */
void StartDefaultTask(void const * argument)
{
/* init code for USB_DEVICE */
MX_USB_DEVICE_Init();
/* init code for FATFS */
MX_FATFS_Init();
/* USER CODE BEGIN StartDefaultTask */
/* Infinite loop */
for(;;)
{
run_test();
calc_values();
//=> this causes the linker error osDelay(100);
}
/* USER CODE END StartDefaultTask */
}
/* USER CODE BEGIN Application */
/* USER CODE END Application */
could you give me a hint why this is not working?
