Re: [Caml-list] Segfault in C++ stub with many 'new' allocations

[Samuel Hornus <Samuel.Hornus@inria.fr>]

On 17 nov. 2012, at 20:10, Török Edwin wrote:

> On 11/17/2012 08:42 PM, Samuel Hornus wrote:
>> 
>> Regarding my first question, if it can help, here is the relevant part of my C++ code:
>> extern "C" value ann_create_bd_tree_flat_ba (value ba, value n, value dim)
>> {
>>    CAMLparam3(ba,n,dim);
>>    ANNbd_tree * ptr = create_bd_tree_flat((ANNcoord*)Caml_ba_data_val(ba), Int_val(n), Int_val(dim));
>>    CAMLreturn ((value)ptr);
> 
> I don't think this is safe. Shouldn't the return value be wrapped in a custom block?
> If the GC tries to interpret this as an OCaml value (which it isn't) it might crash.

Currently, as advised in F. Monier webpage http://www.linux-nantes.org/~fmonnier/ocaml/ocaml-wrapping-c.php#ref_finalise, I wrap the pointer, in the OCaml code, inside an abstract OCaml type with a finalizer. Could there still be problems with the GC ?
That being said, my crash happens *inside* the C++ constructor, well before the garbage collection may have kicked in. The same code, compiled as a pure C++ program works without problem, even with millions of points.
Is it possible that C++ called from OCaml has a limited memory allocation space?
-- 
Sam