RE: Understanding GDB frames

[Nick Roberts <nickrob@snap.net.nz>]

 > It seems at the MI interface one wants a choice of whether a varobj
 > is associated with:
 >   (a) a specific frame (goes away when function returns)
 >   (b) a function
 >   (c) a function at the same depth (which some implement)

GDB already does something like (b) if you use:

-var-create - @ myvar

although it's not documented.  I think this can specifically be used in the
case of recursion

 > How the distinction is made at the GUI level is a separate question.
 > And what to do in the event of recursion when one selected a
 > function-level varobj (b) is also an interesting question -- perhaps
 > it always refers to the topmost instance (or to theseparately selected
 > instance if the currently selected stack depth is to that function).
 > 
 > That way, (b) and (c) have less performance impact, and one of them
 > could be the default.  And (a) being optional, could be fully supported
 > like watchpoints by setting a breakpoint at the return PC, even though
 > it has a performance hit (especially in the presence of recursion).
 > 
 > And perhaps MI docs could even document this  ;-)

If you want this functionality in GDB then I think you will have to contribute
it.

-- 
Nick                                           http://www.inet.net.nz/~nickrob