[Gc] Determining if pointer GC allocated

[Hans Aberg]

On 21 Dec 2011, at 01:35, Henning Makholm wrote:

>> Is there a function to check if a pointer has been allocated by the
>> GC? That is, something like
>>   bool is_on_heap(void* p);
>> that returns true exactly when p has been allocated by the GC.
>> And would such a function be time consuming?
> 
> Check whether GC_base(p) returns 0.

Thanks! I saw this function, but did not realize it could be used.

How time-consuming is this call?

Hans