[cffi-devel] A question about arrays and enums

[nitralime]

Hello Luis,

Thank you for your reply!

>>  (defcenum (:a 1) ... (:c #.(logior 1 2)) ...).

My point regarding "enum" definition was actually if it is
possible to write down a definition of enum in CFFI without
breaking the "abstraction". In the body of enum as you see
there is an interdependency between the fields of enum
being defined: the value of c depends on a and b and
the value of d depends on c.

 >> but it has some limitations and it's
 >> undocumented (see src/types.lisp).

With that CFFI array type "*/typedef char XXX[8]/*"
can be translated now as "/*(defctype XXX (:array :char 8))*/"!

What are those limitations?

Regards
Nik

On 03/07/2011 11:14 AM, Luís Oliveira wrote:
> Hello Nik,
>
> On Mar 2, 2011 6:01 PM, "nitralime"<nitralime at googlemail.com>  wrote:
>> Hopefully here is the right place to ask CFFI user related questions.
>> What would be an appropriate CFFI definition for the following C entities?
>>
>> 1) typedef enum {
>>         a = 0x01,
>>         b = 0x02,
>>         c = a | b,
>>         d = 0x04 | c
>>     } test;
> It's a bit cumbersome to express that with CFFI. Something like
> (defcenum (:a 1) ... (:c #.(logior 1 2)) ...).
>
>
>> 2) typedef char XXX[8];
>>
>> How are the C arrays handled in CFFI?
> There are some array operations such as mem-aref, and you can allocate
> them using foreign-alloc. defcstruct supports arrays via :count.
> There's also an :array type that will convert C arrays to Lisp arrays,
> but it has some limitations and it's
> undocumented (see src/types.lisp).
>
> HTH,
>
> --
> Luís Oliveira
> http://r42.eu/~luis

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