Re: ffi docs

[Ludovic Courtès]

Hi!

Neil Jerram <address@hidden> writes:

>>    Void pointers may be accessed as bytevectors.
>>
>>  -- Scheme Procedure: foreign->bytevector foreign [uvec_type [offset
>>           [len]]]
>>  -- C Function: scm_foreign_to_bytevector foreign uvec_type offset len
>>      Return a bytevector aliasing the memory pointed to by FOREIGN.
>>
>>      FOREIGN must be a void pointer, a foreign whose type is VOID. By
>>      default, the resulting bytevector will alias all of the memory
>>      pointed to by FOREIGN, from beginning to end, treated as a `vu8'
>>      array.
>
> It feels like we're missing a unification trick here.
>
> Thought #1: if we have, e.g., an int8 pointer ip, why not just use
> (foreign-ref ip n) to interpret the pointer as pointing to an array, and
> get its nth element?
>
> Thought #2: but if we do that we'll be duplicating the bytevector API.
> So instead, shouldn't the fundamental operation be (foreign->bytevector
> NAME TYPE LIBRARY [LEN]), and get/set then done using the bytevector
> API?

Andy and I discussed it at GHM, which led to this simplification of the API:

  
http://git.savannah.gnu.org/cgit/guile.git/commit/?id=d4149a510e4a87915b625255f4de3301510d810c

There are a few more changes coming: renaming some of the procedures
from ‘foreign’ to ‘pointer’, and adding more convenience procedures
(C string manipulation notably).

Thanks,
Ludo’.