Re: Ada array vs C pointer (call by reference)

[Robert A Duff <bobduff@shell01.TheWorld.com>]

Keith Thompson <kst-u@mib.org> writes:

> Interfaces.C.C_Float, which (assuming the Ada implementation gets it
> right), is guaranteed to match C's float, or of using Float, which has
> no such guarantee (but saves a little typing).  Why would you even
> consider using Float?

You might have a program that uses Float all over the place,
and you want to add some interface to C in one tiny corner
of that program.  You might be tempted to use Float at the
interface to C in order to avoid a lot of type conversions.

It's a pretty good bet that Ada's Float and Ada's Interfaces.C.C_Float,
and C's float are all represented the same.  If you're using GNAT,
I think the documentation guarantees that.

But you're right -- the "right" way to interface to C is to use the
types in Interfaces.C, and use pragma Convention when you declare
your own types.

- Bob