Re: Reporting of "program no longer exists"

[Daniel Jacobowitz <drow@false.org>]

On Sat, Oct 14, 2006 at 08:33:16PM +0400, Vladimir Prus wrote:
> 
> Hi,
> suppose a program being debugged got SIGSEGV and the user for GUI frontend 
> tries the "next" command. Here's what happens:
> 
>    (gdb) -exec-next
>    ^running
>    *stopped,reason="signal-received",signal-name="SIGSEGV".....
>    (gdb) -exec-next
>    ^running
>    Couldn't get registers: No such process.
>    ^error,msg="Couldn't get registers: No such process."

This is simply a bug.  Try it from the CLI:

(gdb) r
Starting program: /bin/cat
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)
(no debugging symbols found)

Program received signal SIGSEGV, Segmentation fault.
0x00002aaaaac7f352 in __read_nocancel () from /lib/libc.so.6
(gdb) n
Single stepping until exit from function __read_nocancel, 
which has no line number information.

Program terminated with signal SIGSEGV, Segmentation fault.
The program no longer exists.
(gdb) 

-exec-next ought to report ^running and then that the program has
exited (is that ^exited?).  So I'd look at where the error came from.

> (1) How can frontend disable the "next" command? Checking for "SIGSEGV" is 
> possible, but it a bit of a hack.

It's wrong.  We don't know yet that the SIGSEGV will be fatal.  If the
application has a signal handler installed for SIGSEGV, when you
continue the handler will be executed, and life will go on.

-- 
Daniel Jacobowitz
CodeSourcery