Comment author: administrator

The data pointer in the caml_bigarray struct is not allocated and deallocated
consistently in bigarray_stubs.c. Somtimes stat_alloc is used and sometimes
malloc is used, but stat_free is never used. For example, in the latest cvs
sources (Oct 30, 17:00 PST):

94: data = stat_alloc(size);
653: b->data = malloc(elt_size * num_elts);
400: free(b->data);
403: free(b->proxy->data);

I agree it's a bit of a mess :-) We can't use stat_alloc() on line 653
because it may raise an exception, while we are not allowed to raise
exceptions in the middle of an input_value operation.

Concerning the free() on lines 400 and 403, the idea is that some C
code can create a Caml bigarray via alloc_bigarray, passing it data
allocated with the standard malloc(), and requesting (via the
BIGARRAY_MANAGED flag) that OCaml calls free() on the data when the
bigarray dies.

It seems that stat_alloc/stat_free should always be used for
consistency (and if the runtime wants to do some tracking/debugging
underneath).

I agree that stat_alloc and stat_free should always be used in pairs
for the reason you mention. Given the constraints I mentioned above,
this means that the stat_alloc on line 94 should be replaced by malloc
plus an explicit test on the result...

Best regards,

• Xavier Leroy

Comment author: administrator

Fixed 2001-11-26 by XL