[Gc] Determining if pointer GC allocated

[Hans Aberg]

On 22 Dec 2011, at 01:07, Boehm, Hans wrote:

> IIRC, GC_base() is avoided on the most frequently exercised paths in the collector, though those do very similar things using essentially the same data structures.  But it is essentially a short piece of straight-line code, so it should indeed be quite fast.  Slight improvements are probably possible if you know that the argument is a base pointer.  If you assume the argument is a pointer to a valid object, GC_find_header() != 0 might be a bit faster, though it uses an interface that's not currently exported.

In the application I have in mind, one checks the reference of the user object. The gc.h header says that when debugging allocation, that is not the base pointer.

Hans