Re: C array to ada record interface

[tmoran@acm.org]

>   type B_Ptr is access all B;
>   pragma Convention (C, B_Ptr);
> ...
>       function To_Address is new Ada.Unchecked_Conversion
>          (Source => B_Ptr, Target => System.Address);

  Interesting possible problem:  One of the compilers I use rejected
the Unchecked_Conversion because its System.Address is not the same
size as B_Ptr.  So I dropped the Unchecked programming and used instead

    package B_Ptr_Conversion is new System.Address_To_Access_Conversions(B);
    subtype B_Ptr is B_Ptr_Conversion.Object_Pointer;
which works on three different compilers.  But neither

    pragma Convention (C, B_Ptr);
nor
    pragma Convention (C, B_Ptr_Conversion.Object_Pointer);
is then legal.

The program works without the pragma Convention on all three Ada compilers
I tried, but it's not clear to me that's guaranteed to be OK, and if some
system does need the pragma, is there a compiler-agnostic way to solve
this problem?

(Neither is    pragma Convention (C, Array_With_Known_Length);
legal but that seems even less likely to be necessary.)