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

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

Dear all,

I have two questions.

1/ I'm writing a stub to the C++ ANN library [1] to find geometric neighboring points in space.
The constructor of the main class in this library uses a lot of allocation with the "new" C++ keyword.
For small input point sets (e.g. 2500 points), it all seems to work fine.
For larger ones (50 K points), the C++ constructor crashes.
My question is : is it possible that the C++ "new" allocator differs sufficiently from the C-style malloc, that bad interactions with OCaml heap happen ?

(I'm passing the input points coordinates in a plain bigarray.)

2/ Regarding bigarray: before using them, I let the C++ constructor access, and keep pointers inside regular OCaml [float array] or [float array array]. It was working well (again, for small input point set), but is that safe ? Or can the garbage collector eventually relocate the content of a  [float array]  or of a [float array array] ? so that the pointer kept in the C++ class would become dangling ?

Thank you in advance,
Sam

[1] Approximate Nearest Neighbors http://www.cs.umd.edu/~mount/ANN/