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From: Simon Wright <simon@pushface.org>
Newsgroups: comp.lang.ada
Subject: Re: Least Dangerous Way to Do This ?
Date: Mon, 15 Oct 2018 17:05:33 +0100
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Date: 2018-10-15T17:05:33+01:00
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patrick@spellingbeewinnars.org writes:

> I need to interface with automatically generated C. function pointers
> are represented as a pointer to a pointer to a char. This is weird but
> done for pointer arithmetic purposes.

But it's not really a char**, is it!

   procedure Pointers is
      type Procedure_P is access procedure with Convention => C;
      type Procedure_P_P is access Procedure_P;
      P : Procedure_P_P;
      procedure Proc is null with Convention => C;
   begin
      P.all := Proc'Access;
   end Pointers;

You could try something involving Proc'Address, though it's not obvious
that that's mandated to be the address of something that you could
call. Maybe convention C does that.