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Subject: Re: GNAT and Memory Maps?
References: <pan.2003.07.05.03.42.01.638542.1720@nomail.com>
From: Ludovic Brenta <ludovic.brenta@insalien.org>
Date: 05 Jul 2003 15:10:36 +0200
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Date: 2003-07-05T15:10:36+02:00
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Freejack <Freejack@nomail.com> writes:

> I've been picking through the GNAT docs (and Ada docs in general) in an
> attempt to figure out how/if and when/why the Ada compiler might choose to
> use an mmap system call in deference to a malloc/calloc or alloca call.
> 
> Basically, I'm doing some low level routines and I need explicit control
> over what pages are swapped and when. ( mmap() mlock() munlock() and
> munmap() are the usual C functions for handling this.)
> 
> I'm using Linux at the moment, and I could just as easily use the native C
> library (glibc). However, I want to handle this entirely in Ada. I'm using
> the No_Run_Time Pragma.
> 
> Note: I'm also a Forther, so the idea of explicit memory and device
> handling doesnt frighten me. ;->
> 
> (Hmmm...now theres an experiment to try sometime. A Subroutine Threaded
> Forth VM in Ada.)


My first idea is to use your own storage pool; see ARM 13.11 for
information on storage pools. However, I'm not sure this approach
works with pagma No_Run_Time.

By the way, I came across a post by Robert Dewar where he said
No_Run_Time is obsolete.  Here is the URL:

http://gcc.gnu.org/ml/gcc/2002-11/msg00321.html

What is your situation?  Are you writing a Linux kernel module in Ada?
(that's the only reason I can think of to use No_Run_Time) In this
case, I'm not sure you can use glibc either.

-- 
Ludovic Brenta.