Re: [Caml-list] GC with C issues

[Damien Doligez <damien.doligez@inria.fr>]

On Feb 3, 2005, at 12:31, ronniec95@lineone.net wrote:

>>  Field (retVal, 0) = (value) x;
>
> Hmm... I thought I was only supposed to do that when using
> alloc_small/alloc_shr interface? However using your method does work in
> this small example though I'm worried about if something unexpected 
> will
> happen in more 'real-life' code...

Since retVal has the "Abstract" tag, its contents is none of the GC's
business, so you don't need to use Store_field to tell it about
assignments.

On the other hand, depending on the bit-pattern of (the value of) x,
you might crash the GC if you use Store_field.  In this case, x is an
aligned pointer outside the heap, so you're safe either way.

But the proper way is to store directly with Field.

If you want to be pedantic, it's not really a field but a bunch of bytes
so the even more proper way is to write:

   * (someObject *) Bp_val (retVal) = x;

-- Damien