Re: examining mmap()'d memory regions on linux

[Andrew Cagney <ac131313@cygnus.com>]

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Kevin Hilman wrote:
> 
> I have an app that reads/writes to an mmap()'d region.  The data
> is being read and written fine because it's getting to it's final
> location (in this case a hardware device).
> 
> However, if I try to examine (via 'x') these memory regions in gdb, I
> always get zeros.
> 
> Does gdb support mmap()'d regions?

Not a GDB problem.  GDB asks the kernel ``can I have memory at address X
with process P''.  If the kernel doesn't return it there is little GDB
can do :-)

As a work around, you may want to add a small function to your program
that dumps out the relevant data.  You can then call that from the gdb
command line.

	enjoy,
		Andrew
From ac131313@cygnus.com Thu May 18 01:08:00 2000
From: Andrew Cagney <ac131313@cygnus.com>
To: GDB Discussion <gdb@sourceware.cygnus.com>
Subject: GDB diagram
Date: Thu, 18 May 2000 01:08:00 -0000
Message-id: <3923A4A7.8506C817@cygnus.com>
X-SW-Source: 2000-05/msg00084.html
Content-length: 365

Just FYI,

    http://www.cygnus.com/~cagney/gdb-1999-07.jpg

this is something that I copied from a white board during a GDB
discussion.  Some 8 months later it is interesting to see what has and
what hasn't worked.

In the next week I'll try to come up with something that more closely
resembles reality.

	Andrew

PS: Yes the top left does say ``visual basic''.
From robert.melchers@drives.eurotherm.co.uk Thu May 18 08:05:00 2000
From: "Robert" <robert.melchers@drives.eurotherm.co.uk>
To: "Gdb Mailing list (E-mail)" <gdb@sourceware.cygnus.com>
Subject: gdb/mi question
Date: Thu, 18 May 2000 08:05:00 -0000
Message-id: <000301bfc0da$a244e1d0$c9a87995@rmelch.drives.eurotherm.co.uk>
X-SW-Source: 2000-05/msg00085.html
Content-length: 625

I have build gdb 
with -DUI_OUT=1 and now I get the following error when I 
type
 
/tools/H-i686-pc-cygwin/bin/sh-coff-gdb --ui=mi 
--nw Interpreter `mi' unrecognized.
 
All other 
combinations of --interpreter --i --ui all generate the same 
message.
 
I passed the 
following to configure --enable-build-warnings=-DUI_OUT=1 
 
I want to do this so 
that I my pipe commands to and from gdb. Have I entirely missed the point ?? or 
am I on the right track ?
 
Also I cant see 
where _initialize_mi_main() is called from. I am guessing that once I understand 
this The rest may fall into place.
Robert Melchers R&D