what is the function of EXCEPTIONS_SIGLONGJMP?

[Jan Kratochvil]

On Thu, 13 Sep 2012 11:55:34 +0200, John Smith wrote:
>    when I  debug gdb using gdb self ,  after I  type "start" command ,
>  the prompt  is  as  below :
>        Warning:
>       Cannot insert breakpoint 0.
>       Error accessing memory address 0xdb6a5194: /.
>       0xb7589571 in siglongjmp () from /lib/i686/cmov/libc.so.6
> 
>  it seem to be some exceptions  happened  when  dealing with  break points  .

You are trying to step over longjmp or siglongjmp call.  This is supported
only with SystemTap-extended glibc, this is implemented only in recent glibc
and recent GDB.  Recent Fedora releases also have it working.
glibc/
	commit 8422c9a560e6e3c854739c8a13ecb1c6714f930f
	Author: Roland McGrath <roland@hack.frob.com>
	Date:   Fri May 25 13:31:57 2012 -0700
	    Add systemtap static probe points in setjmp/longjmp on x86.
gdb/
	commit 014135139c612fe1fbe6f11d2350f72325a66f7c
	Author: sergiodj <sergiodj>
	Date:   Fri Apr 27 20:48:52 2012 +0000
	    2012-04-27  Sergio Durigan Junior  <sergiodj@redhat.com>
			Tom Tromey  <tromey@redhat.com>

I just do not understand how that can happen during 'start' command, 'start'
is just doing 'tbreak' and 'run', there is no stepping involved anywhere.


Regards,
Jan