questions on debug informations used by gdb

[Roul Oldenburger <oldenburger dot roul at stn-atlas dot de>]

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