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

[Phil Muldoon]

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