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From: mheaney@on2.com (Matthew Heaney)
Newsgroups: comp.lang.ada
Subject: Re: [Spark] Arrays of Strings
Date: 9 Apr 2003 10:42:50 -0700
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Lutz Donnerhacke <lutz@iks-jena.de> wrote in message news:<slrnb95ehu.ob.lutz@taranis.iks-jena.de>...
> In order to implement thin an execve binding, I wonder how to emulate the
> C-Type "char const * const x []". Any bright ideas?

Realize that an array in C "decays" to a pointer to the first element,
so x has the type

  const char* const*

If you want to use the char* type in Interfaces.C.Strings, then your
problem reduces to:

  type chars_ptr_access is access constant C.Strings.chars_ptr;
  for chars_ptr_access'Storage_Size use 0;
  pragma Convention (C, chars_ptr_access);

Now just declare an array of aliased chars_ptr, e.g.

  type chars_ptr_array is (Natural range <>) of aliased chars_ptr;
  pragma Convention (C, chars_ptr_array);

  argv_array : constant chars_ptr_array := ...;
  argv_ptr : constant chars_ptr_access := argv_array (0)'Access;

  execv(filename, argv_ptr);


Interestingly, the chars_ptr_array declared in RM95 B.3.1 (6) does not
declare its component subtype as aliased, nor is the array marked as
begin C-compatible.  This seems wrong to me, which is why I declared
the chars_ptr_array type myself, as above.