I've got the gdb source in Scratchbox 2 with Maemo patches applied by
running this:
sb2 -e dget -x
http://repository.maemo.org/pool/diablo/free/g/gdb/gdb_6.6.dfsg-1+armel+osso1.dsc
I'm just trying to figure out how to link gdb with libqthreads. There
doesn't seem to be any way to do it in gdb's configure script.
Does anyone know how to do it?
On Thu, May 28, 2009 at 11:52 AM, Neil Hooey <nho...@gmail.com> wrote:
> Thanks Mika, that partially helped.
>
> Now when I try to debug the simple Qt program, I get errors with gdb
> not being able to find the user-level thread. This is the same simple
> single-threaded Qt program I mentioned in the first post.
>
> While debugging the same Qt program outside of Scratchbox 2, the
> breakpoints work fine.
>
> While debugging a regular C program that does nothing more than
> printf, inside of Scratchbox 2, the breakpoints work fine.
>
> So it seems that a simple Qt program spawns a new thread. I read in
> the "Maemo SDK+ Debugging Guide" that gdb needs to be linked against
> the same thread library the application is using. So does gdb for
> Scratchbox 2 need to be linked against libqthreads? How would you do
> that?
>
> Here is the transcript and error:
>
> (sb2-emulate-gdb) sb2-prepare
> Function "_dl_debug_state" not defined.
> Breakpoint 1 (_dl_debug_state) pending.
> (sb2-emulate-gdb) run
> Starting program: ./program
> Breakpoint 2 at 0xb80a6340
> Pending breakpoint "_dl_debug_state" resolved
> warning: Temporarily disabling breakpoints for unloaded shared library
> "/lib/ld-linux.so.2"
> Breakpoint 2 at 0xb80a63c3
> [Thread debugging using libthread_db enabled]
> Error while reading shared library symbols:
> Cannot find new threads: generic error
> Cannot find user-level thread for LWP 3639: generic error
>
> On Thu, May 28, 2009 at 10:55 AM, Mika Westerberg
> <ext-mika.1.westerb...@nokia.com> wrote:
>>
>> On May 28, 2009, at 9:24 AM, Westerberg Mika.1 (EXT-Nixu/Helsinki) wrote:
>>
>>>
>>> On May 27, 2009, at 6:02 PM, ext Neil Hooey wrote:
>>>
>>>> I wrote a very simple Qt program that works just fine. Here is the
>>>> source:
>>>>
>>>> #include <QApplication>
>>>> #include <QPushButton>
>>>> int main(int argc, char* argv[]) {
>>>> QApplication app(argc, argv);
>>>> QPushButton button("Hello", &frame);
>>>> button.resize(50, 50);
>>>> button.move(100, 100);
>>>> button.show();
>>>> return app.exec();
>>>> }
>>>>
>>>> When I try to debug it in gdb, setting a breakpoint in main in the way
>>>> that scratchbox-specific gdb instructs you to doesn't actually get
>>>> caught:
>>>>
>>>> $ gdb ./qt-program
>>>> GNU gdb 6.8-debian blah blah blah
>>>> Welcome to scratchbox2 enabled gdb!
>>>> ================================
>>>> Before starting target program you should run command 'sb2-prepare'
>>>> that sets breakpoint which is used to stop target before its main()
>>>> gets called. After the breakpoint is hit, you are able to set
>>>> furtherbreakpoints and do normal debugging actions.
>>>> ================================
>>>> (sb2-emulate-gdb) sb2-prepare
>>>> Function "_dl_debug_state" not defined.
>>>> Breakpoint 1 (_dl_debug_state) pending.
>>>> (sb2-emulate-gdb) run
>>>> Starting program: /home/nhooey/code/fun/testTable/testTable
>>>> QGtkStyle cannot be used together with the GTK_Qt engine.
>>>> Qt: Session management error: Could not open network socket
>>>> ### The program runs, but no breakpoint is caught
>>>
>>> It seems that gdb support in sb2 is broken again. I was able to
>>> reproduce the bug
>>> here so I will start to investigate it right now.
>>
>> Further investigation shows that gdb has been upgraded to version 6.8 which
>> somehow (no glue yet) breaks sb2 debugging. Workaround is to downgrade gdb
>> in rootstrap to this version:
>>
>> http://repository.maemo.org/pool/diablo/free/g/gdb/gdb_6.6.dfsg-1+armel+osso1_i386.deb
>>
>> Just download the file and run:
>>
>> % sb2 -eR dpkg -i gdb_6.6.dfsg-1+armel+osso1_i386.deb
>>
>> after this debugging hopefully works again.
>>
>> We will continue investigation for the root-cause of this problem.
>>
>> MW
>> _______________________________________________
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>> Scratchbox-users@lists.scratchbox.org
>> http://lists.scratchbox.org/cgi-bin/mailman/listinfo/scratchbox-users
>>
>
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