Re: Interfacing to C library...

["Eric G. Miller" <egm2@jps-nospam.net>]

In <n0zw9.2139$bG.200@rwcrnsc53>, tmora wrote:

>> > I'm working on building an interface to a C library where most of the
>   The Windows bindings available at www.adapower.com do a lot of this.
> 
>> Then write another package that is "thicker", and takes advantage
>> of Ada features like exceptions.
>   For an example of a thick binding, may I modestly suggest you look
> at the source code for Claw available at www.adapower.com
>   The TriAda paper available at
> www.rrsoftware.com/html/prodinf/triadapaper/triada.html
> has a discussion of some the decisions to be made for a thick, Ada-style,
> binding.  Also, IEEE Std 1003.5-1992, on the Ada binding to POSIX,
> also discusses many of these issues.

Okay, how to handle:

/* C header */
struct foo { ... }

long pass_by_value (struct foo); 


-- Ada Spec
type foo is record ... end record;
pragma Convention (C, foo);

function Pass_By_Value (bar : foo) return Long_Integer;
pragma Import (C, Pass_By_Value, "pass_by_value");


Seems Ada always passes records via C pointers. So, the above
doesn't work. Surely, there's a way!  Or do I need a C wrapper for
my Ada wrapper ;-(