Re: [patch] Do not allow unwinder to terminate inferior in an inferior function call if a C++ exception handler cannot be found.

Phil Muldoon
2009-04-27T08:58:22Z

Eli Zaretskii wrote:
>> + add_setshow_boolean_cmd ("unwind-on-terminating-exception", no_class,
>> + &unwind_on_terminating_exception_p, _("\
>> +Set unwinding of stack if a std::terminate() call originates from\n\
>> +the default C++ exception handler."), _("\
>> +Show unwinding of stack if a std::terminate() call originates from\n\
>> +the default C++ exception handler."), _("\
>>
>
> This is not good: the first sentence of a doc string should not take
> more than one screen line, because various help commands, such as
> `apropos', display only the first line. How about
>
> Set unwinding of stack if std::terminate is called while in call dummy.
>
> ?
>

That's fine with me. I did not know that about apropos, thanks for the
tip. I'll add it to my patch list.

>> +The unwind on terminating exception flag lets the user determine\n\
>> +what gdb should do if a std::terminate() call is made from the\n\
>> +default exception handler.\n\
>> +The default is to unwind the frame."),
>>
> This doesn't tell what happens if it's set to OFF.
>
>

I actually thought about this, but the off behaviour is just how GDB
"used to be". Something like: "If the flag is set to be 'off', GDB
will allow the inferior to be terminated by the default exception handler."?

>> +Similarly, with a C++ program it is possible for the function you
>>
>
> Please use C@t{++} (here and elsewhere), it looks better in the
> printed manual.
>
>

Thanks, noted and corrected.

>> +call via the @code{print} or @code{call} command to generate an
>> +exception that is not handled due to the constraints of the dummy
>> +frame.
>>
>
> I think ``due to the constraints of the dummy frame'' needs an
> explanation. I'm quite sure many C++ programmers will not immediately
> grasp the nature of the problem.
>

I'll add a brief narrative explaining why the unwinder can only see the
dummy frame, and incorrectly infer that there are no more frames to
check for an exception handler.

>
>> +Set unwinding of the stack if a C++ exception is raised but unhandled
>>
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> either
> exception is raised, but left unhandled
>
>

I'll use that one, thanks.

>> If set to off, @value{GDBN} the exception is delivered to
>> +the default C++ exception handler.
>>
>
> This means the debuggee will be terminated, right? If so, we should
> mention that explicitly.
>
>

Noted, and changed.

> Other than that, the patch for the manual is approved.
>

Thanks for the swift review!

Regards

Phil Muldoon