So I can safely do this? (Macro rewritten as inline function)
static inline __attribute__((always_inline)) BOOL objc_isSmallObject(id obj)
{
return (((intptr_t)obj) & 1) ? YES : NO;
}
在 2013-6-8，上午4:10，David Chisnall <[email protected]> 写道：
> On 7 Jun 2013, at 16:29, Luboš Doležel <[email protected]> wrote:
>
>> for toll-free bridging in CoreBase, I need a way to detect whether the
>> incoming pointer is a small object encoded in a pointer and act accordingly
>> (treat it as an ObjC object and avoid reading it).
>
> In objc/runtime.h, there is a constant SMALL_OBJECT_MASK. If ptr &
> SMALL_OBJECT_MASK == 0, then the pointer is not a small object.
>
> On 32-bit platforms, the low bit of the pointer will be 0. On 64-bit
> platforms, the low 3 bits will always be zero.
>
> David
>
>
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