Re: C binding issue

[Jeffrey Carter <spam@spam.com>]

David C. Hoos wrote:
 > "kat-Zygfryd" <6667@wp.pl> wrote in message
 > news:b9k0rv$bls$1@news.onet.pl...
 >
 >> Thanks, I just thought that access types and C pointers are
 >> incompatible.
 >
 > Questions of this type are answered in the Ada Reference manual.
 >
 > This particular case is covered in B.3 (68), viz.:
 >
 > An Ada access T parameter, or an Ada out or in out parameter of an
 > elementary type T, is passed as a t* argument to a C function, where
 > t is the C type corresponding to the Ada type T. In the case of an
 > elementary out or in out parameter, a pointer to a temporary copy is
 > used to preserve by-copy semantics.

This refers to access parameters; the example used a named access type.
These can be made C-compatible by applying pragma Convention to them:

type Void_Ptr is access all Integer;
pragma Convention (C, Void_Ptr);

-- 
Jeff Carter
"Beyond 100,000 lines of code you
should probably be coding in Ada."
P. J. Plauger