questions on debug informations used by gdb

questions on debug informations used by gdb

[Roul Oldenburger]

Hello there,

I am quit new to this topic and also to this list. My apologies if I put 
this question in the wrong place.

Instances of datatypes (esp. structures and records in C and Ada) can be 
viewed using gdb ... using ddd also let me click them to view each 
single component.
What I am looking for is the information gdb is using to display the 
name and the value of a structure. More precisely I need the positions 
or lets say offsets and sizes of the structures and their components in 
memory. I am hoping to find all I need in the debug information gcc 
includes into the objectfiles.

Unfortunately I haven't found something like a list of what kind of 
information gcc includes and in what format.

Having seen gdb uses the same information I am looking for, I like to 
know where does it get it from. Probably there are functionalities in 
gdb I might use to extract the same information for my purposes?

And in case the informations I need are included, I also like to know if 
there are differences in format if compile for different platforms and 
/or different machines?

If you could help to answer my questions I would be happy!

Probably my questions seem to be basics for you, so I would be happy if 
somone could send me a link to a document or how-to, to solve them on my 
own.

Thanks a lot
Roul Oldenburger

Re: questions on debug informations used by gdb

[Daniel Jacobowitz]

On Thu, Jul 03, 2003 at 12:40:44PM +0200, Roul Oldenburger wrote:
> Hello there,
> 
> I am quit new to this topic and also to this list. My apologies if I put 
> this question in the wrong place.
> 
> Instances of datatypes (esp. structures and records in C and Ada) can be 
> viewed using gdb ... using ddd also let me click them to view each 
> single component.
> What I am looking for is the information gdb is using to display the 
> name and the value of a structure. More precisely I need the positions 
> or lets say offsets and sizes of the structures and their components in 
> memory. I am hoping to find all I need in the debug information gcc 
> includes into the objectfiles.
> 
> Unfortunately I haven't found something like a list of what kind of 
> information gcc includes and in what format.
> 
> Having seen gdb uses the same information I am looking for, I like to 
> know where does it get it from. Probably there are functionalities in 
> gdb I might use to extract the same information for my purposes?
> 
> And in case the informations I need are included, I also like to know if 
> there are differences in format if compile for different platforms and 
> /or different machines?
> 
> If you could help to answer my questions I would be happy!
> 
> Probably my questions seem to be basics for you, so I would be happy if 
> somone could send me a link to a document or how-to, to solve them on my 
> own.

Your best bet is to take a look at the DWARF specification, and
libdwarf.  See http://reality.sgiweb.org/~davea/.

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer