Re: Returning data from Ada to C

["Alex R. Mosteo" <devnull@mailinator.com>]

Igor Khavkine wrote:
> Thanks for the quick reply.
> 
> On 2005-05-04, Jeffrey Carter <spam@spam.com> wrote:
> 
>>igor.kh@gmail.com wrote:
>>
>>>  /* BTW, is it OK to use Ada allocated memory after `adafinal()'? */
>>
>>No.
> 
> 
> Ok, that's good to know. Also, will I be able to free Ada allocated
> memory with the standard C library `free()'? For example, what do I do if
> I want to free the storage pointed to by `solvec' below?

I'd export a new Ada procedure for this purpose, so you keep all memory 
management in the Ada side. Even if gnat uses malloc internally I guess 
this is safer.

> 
> 
>>>  sols : C_Double_Array; -- This is probably wrong, but `sols' will be
>>>                         -- a C_Double_Array of some size.
>>
>>This won't compile. C_Double_Array is an unconstrained array type. 
>>Objects must be constrained. You probably need
>>
>>Sols : aliased C_Double_Array (<your constraint here);
>>
>>
>>>-- Now I want to return `rcnt' and `sols'
>>>  rcnt := rc;                -- This is the easy part.
>>>  solvec := ???              -- What goes here?
>>
>>Solvec := Sols'Unchecked_Access;
> 
> 
> Great! Now, what type will `Solvec' have? I presume that GNAT will bark at
> me if I use the wrong type.
> 
> Thanks.
> 
> Igor