Message-ID: <3E74B558.3629CBA9@yahoo.com>
Date: Sun, 16 Mar 2003 12:33:12 -0500
From: CBFalconer <cbfalconer AT yahoo DOT com>
Organization: Ched Research
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To: djgpp-workers AT delorie DOT com
Subject: Re: nmalloc revisited
References: <200303141601 DOT RAA26911 AT lws256 DOT lu DOT erisoft DOT se> <3E721051 DOT 645AA67D AT yahoo DOT com>
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CBFalconer wrote:
> 
... snip ...
> 
> Is everybody talking about what I have attached (a zipped htm
> file).  If so, I think mallinfo and mallocmap can be trivially
> implemented without changing nmalloc.  mallocmap can thus ignore
> the level parameter.  malloc_debug is harder, and probably needs
> the malloc hooks, which are not trivially implemented without
> changes, unless a different malloc package is linked using the
> alternative names and an interception package is loaded.
> 
> Actually, without NDEBUG set, the internal names are redefined to
> be malloc, free, and realloc at compilation time.  By changing
> this one definition to redefine as _malloc, _free, and _realloc
> there can be a 10 line generalized package, holding:
> 
>    void *malloc(size_t sz) {return _malloc(sz);}
> 
> etc. and it might cost nothing if defined as inline.  That would
> make inserting the hooks trivial, and nothing existing need be
> changed.  The magic numbers in the malloc-hooks documentation
> would have to go - they are returned by the existing (in nmalloc)
> _sysquery call.  Also nmalloc does not record a duplicate copy of
> block size - I had similar provisions earlier but they adversely
> affect the overhead for 8 byte alignment and people were worried
> about that when I started this project.
> 
>   ------------------------------------------------------------------
>                   Name: malldbg.zip
>    malldbg.zip    Type: Zip Compressed Data (application/x-zip-compressed)
>               Encoding: base64

Nobody has confirmed or denied that the above describes everything
wanted.  At any rate I have added some defines so that:

   gcc -DNDEBUG -DHOOKABLE -o hookmem.o -c nmalloc.c

generates a module with malloc, free, realloc renamed to _malloc,
_free, and _realloc, and includes the following .h file:

/* -------- hookmem.h ----------- */
#ifndef hookmem_h
#define hookmem_h

#include <stddef.h>

void *_malloc(size_t sz);
void _free(void *ptr);
void *_realloc(void *ptr, size_t sz);

#endif
/* -------- hookmem.h ----------- */

What I don't see in the htm file I posted before is any process of
setting those hooks described.  Nor do I find any libc/malloc.h on
my system.  I do find include/malloc.h, which simply includes
stdlib.h.

-- 
Chuck F (cbfalconer AT yahoo DOT com) (cbfalconer AT worldnet DOT att DOT net)
   Available for consulting/temporary embedded and systems.
   <http://cbfalconer.home.att.net>  USE worldnet address!