Re: Coding access to a C's pointer - pointer

["Luke A. Guest" <laguest@archeia.com>]

On 06/06/2020 17:23, Bob Goddard wrote:
> I'm trying to shoehorn net-snmp into an Ada conversion and I've hit a roadblock.
> 
> snmp_synch_response requires a pointer to a pointer:
> snmp_synch_response(netsnmp_session *, netsnmp_pdu *, netsnmp_pdu **)
> 
> Just how the heck do you code that? You can't just declare a System.Address.
> 
> Would I need to drop into C and handle it there?

Yup, C's pointer crap is horrible in Ada.

Essentially, you need to create your types netsnmp_session and netsnmp_pdu.

Let's assume your package name is SNMP.

type Session is null record with
  Convention => C; -- You may has this as an actual full record for al I
know.

You can probably get away with * parameters as "in out" parameters in
the Ada function.

You can do ** by creating a C convention access type to PDU and then
another to that.