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IAR & static_cast<>

Posted by Thomas on June 4, 2008
I'm trying to use FreeRTOS together with C++.

I'm using IAR AVR compiler.

All of FreeRTOS source files are compiled using the C compiler and my own code using Extended Embedded C++ compiler. All the code are compiled and linked togther without errors.

Inspired by a richard_damon post I've made a Runable class, see below.

Running my code I get an RStack warning (JTAGICE mkII)
Wed Jun 04 11:49:06 2008: Target reset
Wed Jun 04 11:49:16 2008: Program exit reached.
Wed Jun 04 11:49:17 2008: The stack 'RStack' is filled to 100% (32 bytes used out of 32). The warning threshold is set to 90.%

I've traced it down to being this static_cast causing the trouble.


If I comment the static_cast and uncomment the loop causing a led to flash everything works fine.

I have tried the same code using winavr c++ compiler and it works. Using the winavr compiler I compile everything using the c++ compiler. Therefore I have to change some cast here and there in the FreeRTOS code in order to satisfy the c++ compiler. When using IAR I can compile a "clean" FreeRTOS (without changing anything) using C compiler and my own code using C++. My guess is that its the reason for my troubles.

Can someone give me an explanation or even a way to fix it?


// runable.c

#include "runable.h"

Runable::Runable(unsigned priority, unsigned stacksize)
#if INCLUDE_vTaskDelayUntil
lastWakeTime = NULL;
xTaskCreate(&run, "", stacksize, this, priority, &handle);

#if INCLUDE_vTaskDelete

#if INCLUDE_vTaskSuspend

void Runable::Suspend()

void Runable::Resume()


#if INCLUDE_vTaskDelay

void Runable::Sleep(portTickType delay)


#if INCLUDE_vTaskDelayUntil

void Runable::SleepUntil(portTickType increment)
if (lastWakeTime == NULL)
lastWakeTime = xTaskGetTickCount();
vTaskDelayUntil(&lastWakeTime, increment);


void Runable::run(void* parm)
PORTA = (PORTA & ~0x01) | (~PORTA & 0x01);

vTaskDelay( 100 );

RE: IAR & static_cast<>

Posted by Richard on June 5, 2008
So the problem seems to be when linking C with C++ code. Is this correct? Can you compile the whole thing as C++ as when using the WinAVR compiler?


RE: IAR & static_cast<>

Posted by Thomas on June 9, 2008
I managed to figure it out. I had some errors in my port causing the stack to be currupt.

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