Re: Why type = <data variable, no debug info>?

[Brian Dessent <brian@dessent.net>]

"Munzir Taha (???? ??)" wrote:
> 
> Hi, in this small program logic tells me that errno and n should have the same
> value displayed in gdb. Am I missing something obvious?

You're probably running into the fact that on modern glibc errno is a
TLS symbol, not a regular one.  This means it can take on a different
value in each thread, and thus is accessed through an indirection.

You might get better debugging ability if you compile with -ggdb3
instead of just -g, which gives gdb some additional information.  I
believe that without any debug information in the binary, gdb cannot do
anything about TLS symbols, but I'm not sure. See also the proposed
patch <http://sourceware.org/ml/gdb-patches/2006-08/threads.html#00187>
and/or <https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=185337>.

Brian