Re: [Qemu-devel] [PATCH v6 1/5] util: Introduce error reporting functions with fatal/abort

[David Gibson <david@gibson.dropbear.id.au>]

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On Tue, Feb 02, 2016 at 10:47:35PM +0100, Thomas Huth wrote:
> On 02.02.2016 19:53, Markus Armbruster wrote:
> > Lluís Vilanova <vilanova@ac.upc.edu> writes:
> ...
> 
> >> diff --git a/include/qemu/error-report.h b/include/qemu/error-report.h
> >> index 7ab2355..6c2f142 100644
> >> --- a/include/qemu/error-report.h
> >> +++ b/include/qemu/error-report.h
> >> @@ -43,4 +43,23 @@ void error_report(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
> >>  const char *error_get_progname(void);
> >>  extern bool enable_timestamp_msg;
> >>  
> >> +/* Report message and exit with error */
> >> +void QEMU_NORETURN error_vreport_fatal(const char *fmt, va_list ap) GCC_FMT_ATTR(1, 0);
> >> +void QEMU_NORETURN error_report_fatal(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
> > 
> > This lets people write things like
> > 
> >     error_report_fatal("The sky is falling");
> > 
> > instead of
> > 
> >     error_report("The sky is falling");
> >     exit(1);
> > 
> > or
> > 
> >     fprintf(stderr, "The sky is falling\n");
> >     exit(1);
> > 
> > I don't think that's an improvement in clarity.
> 
> The problem is not the existing code, but that in a couple of new
> patches, I've now already seen that people are trying to use
> 
>      error_setg(&error_fatal, ... );

So, I don't actually see any real advantage to error_report_fatal(...)
over error_setg(&error_fatal, ...).

> to do error reporting - which is IMHO the most ugliest way to do this,
> because I'd really not expect error_setg() to (always) exit QEMU when I
> quickly read through the sources.
> We fortunately do not have that in the sources yet (only some few spots
> with error_abort), but to prevent that people start using that, it would
> be good to have a error_report_fatal() function instead, I think.
> 
> Alternatively, if you really want to see the exit(1) in the sources, I
> think this should be mentioned in the coding guidelines ... or are you
> fine with error_setg(&error_fatal, ...), Markus?
> 
>  Thomas
> 

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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