Re: Cannot insert breakpoint -1.

[Michael Snyder <msnyder@vmware.com>]

Anmol P. Paralkar wrote:
> On Fri, 24 Jul 2009, Daniel Jacobowitz wrote:
> 
>> On Fri, Jul 24, 2009 at 05:00:45PM -0500, Anmol P. Paralkar wrote:
>>>  Yes, I see:
>>>
>>> (gdb) maintenance info breakpoints Num     Type           Disp Enb
>>> Address    What
>>> -1      shlib events   keep y   0x00110000 <_start>
>>>
>>>  How do I delete it/prevent it from being set? Is this a configure
>> time setting?
>>
>> It may help to use a powerpc-elf debugger instead.
> 
>   I tried powerpc-elf GDB, and it'll work (I see that I cannot set a
>   breakpoint in the application - but that seems to be a problem with
>   the application itself).
> 
>   --
> 
>   I do have one question about powerpc-linux-gnu GDB; I see that the breakpoint
>   is inserted inspite of:
> 
> (gdb) show stop-on-solib-events
> Stopping for shared library events is 0.
> 
>   --
> 
>   From breakpoint.h:
> 
>      /* Some dynamic linkers (HP, maybe Solaris) can arrange for special
>         code in the inferior to run when significant events occur in the
>         dynamic linker (for example a library is loaded or unloaded).
> 
>         By placing a breakpoint in this magic code GDB will get control
>         when these significant events occur.  GDB can then re-examine
>         the dynamic linker's data structures to discover any newly loaded
>         dynamic libraries.  */
>      bp_shlib_event,
> 
>   --
> 
>   I would assume that if stop-on-solib-events is 0, then it ought not to set
>   the -1 breakpoint. Please could you help understanding this part.

Anmol,

"stop-on-solib-events" means 'stop' as in "show the user a gdb prompt".

If it's unset, we still insert the breakpoints so that we can
handle the shared library events (read symbol files), we just
don't go to the interactive prompt.

I think it's really unusual for someone to want to actually
go to the prompt when a shared lib event occurs, but normally
we want symbols to be loaded.  Don't know if there's any way
to actually disable that...

Michael