Lluís Vilanova writes: > Thomas Huth writes: >> On 20.01.2016 15:10, Lluís Vilanova wrote: >>> Thomas Huth writes: >>> >>>> On 18.01.2016 21:26, Eric Blake wrote: >>>>> On 01/15/2016 06:54 AM, Lluís Vilanova wrote: >>>>>> Gives some general guidelines for reporting errors in QEMU. >>>>>> >>>>>> Signed-off-by: Lluís Vilanova <vilan...@ac.upc.edu> >>>>>> --- >>>>>> HACKING | 36 ++++++++++++++++++++++++++++++++++++ >>>>>> 1 file changed, 36 insertions(+) >>>> ... >>>>>> +Functions in this header are used to accumulate error messages in an >>>>>> 'Error' >>>>>> +object, which can be propagated up the call chain where it is finally >>>>>> reported. >>>>>> + >>>>>> +In its simplest form, you can immediately report an error with: >>>>>> + >>>>>> + error_setg(&error_fatal, "Error with %s", "arguments"); >>>>> >>>>> This paradigm doesn't appear anywhere in the current code base >>>>> (hw/ppc/spapr*.c has a few cases of error_setg(&error_abort), but >>>>> nothing directly passes error_fatal). It's a bit odd to document >>>>> something that isn't actually used. >>> >>>> +1 for _not_ documenting this here: IMHO this looks ugly. If we want >>>> something like this, I think we should introduce a proper >>>> error_report_fatal() function instead. >>> >>> That's a bit of a chicken and egg problem. My main intention was to provide >>> a >>> best practices summary on reporting messages/errors, since QEMU's code is >>> really >>> heterogeneous on that regard. But there seems to be no consensus on some >>> details >>> of what the proper way should be with the current interfaces. >>> >>> Utility functions for "regular messages", warnings, fatals and aborts would >>> definitiely be an improvement IMHO, but I dont have time to adapt existing >>> code >>> to these (and I was told not to add unused utility functions for this). >>> >>> Now, if I were able to add such functions, it'd be something like: >>> >>> // Generate message "as is"; not sure if this should exist. >>> message_report(fmt, ...)
>> Not sure what this should be good for? We've already got error_report() >> that generates messages "as is", haven't we? > Well, it just seemed wrong to me using error_report() to report "regular > messages" :) >>> // Generate message with prepended file/line information for the caller. >>> // Calls exit/abort on the last two. >>> error_report_{warn,fatal,abort}(fmt, ...) >>> >>> // Same with an added message from strerror. >>> error_report_{warn,fatal,abort}_errno(fmt, ...) >>> >>> But, should I add these without providing extensive patches that refactor >>> code >>> to use them? >> Maybe create a patch that introduces the _fatal and _abort functions >> (I'd skip the _warn functions for now), and use them in one or two files >> (e.g. replace the error_setg(&error_abort, ...) in spapr.c). That should >> not be that much of work, and could be a good base for further discussion? > I can do that. But then should 'error_fatal' and 'error_abort' be officially > deprecated in favour of error_report_fatal() and error_report_abort()? Sorry, I see this is misleading. I mean deprecate directly using "error_setg(error_fatal)"; you can still decide to pass error_fatal as an error object to other user functions. Cheers, Lluis