Re: Elf and Dwarf from DwflModule life times?

[Roland McGrath <roland at redhat dot com>]

> I'm trying to understand the lifetime of the Elf and Dwarf objects 
> returned by the dwfl_module_getelf and dwfl_module_getdwarf methods.

Everything you get from libdwfl about a particular module is live while
that module is live.  You have to assume it all gets freed and becomes
invalid pointers when the module is removed.  A module gets removed at the
end of a reporting pass that did not report it, when your dwfl_report_end
call will make callbacks to its REMOVED argument.  (And of course all the
modules go away at dwfl_end.)

> Is there anything explaining this, in the header, say?

I don't think it is very clear anywhere.  (I always figured the details of
the reporting stuff might change a little when nontrivial users came along.)

There is a longer-term plan for caching and sharing that will complicate
the situation with the potential for options other than eagerly dropping
everything when a module dies.  (It may soon be about time for that work.)
But the conservative rules for callers now will continue to be safe.


Thanks,
Roland