FreeRTOS get stack size

task.h

/**
 * task.h
 * <PRE>UBaseType_t uxTaskGetStackSize( TaskHandle_t xTask );</PRE>
 *
 * Returns the stack size associated with xTask. That is, the stack
 * size (in words, so on a 32 bit machine a value of 1 means 4 bytes) of the task.
 *
 * @param xTask Handle of the task associated with the stack to be checked.
 * Set xTask to NULL to check the stack of the calling task.
 *
 * @return The stack size (in words) associated with xTask.
 */
UBaseType_t uxTaskGetStackSize( TaskHandle_t xTask ) PRIVILEGED_FUNCTION;

tasks.c

UBaseType_t uxTaskGetStackSize( TaskHandle_t xTask )
{
TCB_t *pxTCB;
UBaseType_t uxReturn;

        pxTCB = prvGetTCBFromHandle( xTask );
        #if( portSTACK_GROWTH < 0 )
        {
                uxReturn = pxTCB->pxEndOfStack - pxTCB->pxStack + 1UL;
        }
        #else /* portSTACK_GROWTH */
        {
                uxReturn = pxTCB->pxStack - pxTCB->pxEndOfStack + 1UL;
        }
        #endif /* portSTACK_GROWTH */

        return uxReturn;
}

Both pxEndOfStack and pxStack are both StackType_t in the kernel,

pxEndOfStack and pxStack are both StackType_t* not StackType_t. Subtracting them will give you the distance apart of the two pointers in units of StackType_t which may be bigger than what can be contained in StackType_t. Compare to uxTaskGetStackHighWaterMark that returns UBaseType_t.

Thanks guys! I've now fixed it :)