Re: Addressing functions

[bobduff@dsd.camb.inmet.com (Bob Duff)]

In article <3citrc$bb5@earth.usa.net>, Bill Buckley <wbuckley@earth> wrote:
> 
> ...I know I can get the address of a subprogram via the ADDRESS 
>attribute in Ada but can not figure a way to use it.

In Ada83, there is no portable way to call such a subprogram.  If you
know the machine-level calling conventions used by your compiler, you
can write a machine code insertion that does, but that's pretty nasty.

In Ada 9X, you can use access-to-subprogram types:

    type String_Procedure is access procedure (S: String);
    X: String_Procedure := Text_IO.Put'Access;

Now you can call X like this:

    X("Hello, world");

which means the same as this:

    X.all("Hello, world");
-- 
Bob Duff                                bobduff@inmet.com
Oak Tree Software, Inc.
Ada 9X Mapping/Revision Team (Intermetrics, Inc.)