About type casting in FreeRTOS Tutorial example 14

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1

hi,

I’ve been studying FreeRTOS using Tutorial.

there’s API function about Timer ID in Software Timer chapter.

void *pvTimerGetTImerID( TimerHnadler_t xTimer);

this function’s type is (void *) so I believe if I wanna type cast this function’s return value to uint32_t, it would be

uint32_t val = (uint32_t *)pvTimerGetTimerID(xTimer);

but according to example 14

static void prvTimerCallback( TimerHandle_t xTimer )
{
TickType_t xTimeNow;
uint32_t ulExecutionCount;

...
 ulExecutionCount = ( uint32_t ) pvTimerGetTimerID( xTimer );
 ulExecutionCount++;
...

it is just ( uint32_t ) not ( uint32_t * ). and it’s working well.

my question is how it’s possible.
if there is something I’ve missed please let me know.

thank you so much.

2

If you want to cast any value to uint32_t, it needs to be ( uint32_t ), regardless of the original type:

uint8_t val1 = 0;
uint16_t val2 = 0;

uint32_t casted_val1 = ( uint32_t ) val1; /* Cast uint8_t to uint32_t. */
uint32_t casted_val2 = ( uint32_t ) val2; /* Cast uint16_t to uint32_t. */

uint32_t * pu32;
void * pv32;

uint32_t casted_pu32 = ( uint32_t ) pu32; /* Cast uint32_t* (i.e. pointer to uint32_t) to uint32_t. */
uint32_t casted_pv32 = ( uint32_t ) pv32; /* Cast void* (i.e. pointer to void) to uint32_t. */
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