[RFC PATCH 0/3] Pretty-printing for errno

[Zack Weinberg]

On Mon, Sep 4, 2017 at 5:25 PM, Pedro Alves <palves@redhat.com> wrote:
>
> FYI, this is now all in gdb master.  I believe all the gdb issues
> uncovered by the errno printer have been addressed.  Let me know
> if you're aware of something still not working properly.

I'm sorry I never got around to experimenting with your patches before now.

With gdb master as of earlier today, and my patched glibc that tries
to pretty-print errno, I can confirm that nearly everything works as
desired. `p (error_t) 0` invokes the pretty-printer, and when
preprocessor macro bodies are available to the debugger (-ggdb3) so
does `p errno`. Unfortunately I am still getting this error message
when I try to print the underlying thread-local errno variable (which
is what `p errno` does if macro bodies are not available):

Cannot find thread-local storage for process 4367, executable file
/home/zack/projects/glibc/glibc-build/stdlib/test-errno-printer:
Cannot find thread-local variables on this target

I don't understand why thread-local variables are inaccessible on my
perfectly ordinary x86_64-unknown-linux-gnu workstation (the base OS
is Debian 'stretch').  Do you have any idea what might be wrong?

zw