[Ecls-list] Ecl version of with-float-traps-masked and vector-sap?

[Raymond Toy]

On Wed, Feb 8, 2012 at 6:01 AM, Juan Jose Garcia-Ripoll <
juanjose.garciaripoll at googlemail.com> wrote:

> On Wed, Feb 8, 2012 at 6:59 AM, Raymond Toy <toy.raymond at gmail.com> wrote:
>
>> Does ecl have the equivalent of cmucl's (and sbcl's)
>> with-float-traps-masked
>
>
> Not yet. This can be implemented using SI::TRAP-FPE
>
> (defmacro with-float-traps-masked (&body body)
>    `(let ((%trap-bits (si::trap-fpe 'cl:last t)))
>      (unwind-protect
>        (progn (si::trap-fpe %trap-bits nil) , at body)
>       (si::trap-fpe %trap-bits t))))
>

This will probably work.  I take it that this will disable all traps?  This
would be the typical expected Fortran mode, so that's perfect.

>
>
>> and vector-sap?
>>
>
> Hmm, is this for the CFFI? Because it is going to depend very much on what
> VECTOR-SAP has to return. For UFFI you have
> SI::MAKE-FOREIGN-DATA-FROM-ARRAY which takes an array and returns an UFFI
> pointer. Alternatively, C-INLINE may be easily used to retrieve the pointer
> in a C format.
>

Thanks for the tips.  I'm not very familiar with cffi or uffi.  Basically,
vector-sap needs to return something that can be made into a pointer for a
foreign function to use as the address of an array/vector.


>
> Oh, I also need the equivalent of without-gcing.
>>
>
> You only need them to keep the arrays from gc, but this can be ensured by
> simply storing the arrays in special or local variables. ECL never moves
> data around: it relies on conservative garbage collectors.
>

Ok.  I'll make sure the arrays are stored in local (lexical) variables, if
they aren't already.

Thanks,

Ray
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