Basile STARYNKEVITCH a écrit :
>>
>> Why do these functions not follow the usual CAMLparam/CAMLreturn macro 
>> stuff?
> 
> Because they are written by the Ocaml guys (Damien knows really well the 
> Ocaml garbage collector; he wrote it). And also, because these 
> particular functions do not do any allocation of Ocaml values (either 
> directly or indirectly).

So, no allocation of OCaml values (or in place modification, either, I 
guess) implies no need for CAMLparam/CAMLreturn stuff?

> My advice for people coding C code for ocaml is the following:
> 
> 1. *always* use the CAMLparam/CAMLreturn/... macros.
> 
> 2. if you dare not using them for some very few functions (because they 
> don't allocate, ...) add a big fat comment with a warning inside.
> 
> Regards

I want to understand them so that I can abstract away in some other file 
/ .so, some rather usual constructs involving OCaml structures. I think 
it is smarter to take some time doing this, with detailed comments all 
over, than repeating the same mistakes over and over (or worse: 
wondering if you made mistakes) when doing C bindings.

All the best,

-- 
      Guillaume Yziquel
http://yziquel.homelinux.org/