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

On 11/17/2012 08:42 PM, Samuel Hornus wrote:
> 
> On 17 nov. 2012, at 19:35, Kakadu wrote:
> 
>> 2) AFAIR there are functions like register_global_root which prevents GC from moving values.
> 
> Thank you Kakadu. It is interesting to know that one can use this function directly. I knew its existence only through the CAML[x]param* macros…
> 
> 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.

--Edwin