Re: Access types for procedures

[Jon S Anthony <jsa@synquiry.com>]

Mark Rutten <Mark.Rutten@dsto.defence.gov.au> writes:

> -- Instantiate a generic package which is basically going to
> -- queue up messages on an entry to a task and then
> -- consecutively call blah with each new message.
> --
> package New_Effector is new G_Effector(
>     in_name=> "output",
>     in_procedure => blah);

Put this in a library level package.  It can be the entire package.

> The generic package has a single externally accessible
> procedure, called Effect, which has the same declarative
> form as blah, i.e.
> procedure Effect(msg: in Message);
> 
> The message declarations are in their own package, which
> includes the definition of the procedure access type
> type Effector_Procedure is access procedure(msg: in message);

By instantiating the generic in your main procedure, the resulting
Effect procedure has a deeper (1 level) scope than the procedure
access type which is defined in the (presumably) library level package
with the message decls and such.  This causes the access level
mismatch.

> However I can insert the above code into a package and
> supply a procedure in this package which creates and
> sends the message. I can then get the same functionality
> as above by calling this procedure from the main procedure,
> but then this error does not appear and everything works
> happily.

Right - the resulting procedure from the instantiation is still at
library level in this case.

/Jon

-- 
Jon Anthony
Synquiry Technologies, Ltd., Belmont, MA 02178, 617.484.3383
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