[petsc-dev] SETERRQ in fortran

[Lisandro Dalcin]

Maybe I'm missing something, but maybe this define is all what you need?

#define SETERRQ(ierr) if (ierr/=0) call PetscError(comm,ierr,0,"message")

program main
  integer ierr,comm
  call something(ierr); SETERRQ(ierr)
end program main



On 6 January 2018 at 02:33, Smith, Barry F. <bsmith at mcs.anl.gov> wrote:
>
>
>> On Jan 5, 2018, at 5:00 PM, Jed Brown <jed at jedbrown.org> wrote:
>>
>> "Smith, Barry F." <bsmith at mcs.anl.gov> writes:
>>
>>>> On Jan 5, 2018, at 4:18 PM, Jed Brown <jed at jedbrown.org> wrote:
>>>>
>>>> "Smith, Barry F." <bsmith at mcs.anl.gov> writes:
>>>>
>>>>>> On Jan 5, 2018, at 12:45 PM, Jed Brown <jed at jedbrown.org> wrote:
>>>>>>
>>>>>> "Smith, Barry F." <bsmith at mcs.anl.gov> writes:
>>>>>>
>>>>>>>> On Jan 4, 2018, at 5:10 PM, Blaise A Bourdin <bourdin at lsu.edu> wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>> On Jan 4, 2018, at 3:16 PM, Smith, Barry F. <bsmith at mcs.anl.gov> wrote:
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> It's changed a bit.  It is better but you need to understand how the new one works, so take a few minutes to see how it works before converting.
>>>>>>>> Got it.
>>>>>>>> An example or a link to the fortran macro definition from the man page would be nice
>>>>>>>> I am confused about the rationale for putting the endif in the macro, though.
>>>>>>>
>>>>>>> It matches the C paradigm
>>>>>>
>>>>>> Hardly.
>>>>>
>>>>>  It matches the paradigm as close as can be reasonable done.
>>>>>
>>>>>  I debated putting the then into the macros also.
>>>>>
>>>>>> #define SETERRQ(c,ierr,s)  then ;call PetscError(c,ierr,0,s);return;endif
>>>>>
>>>>>  So usage would be
>>>>>
>>>>>     if (bad) SETERRQ();
>>>>>
>>>>> would that be better.
>>>>
>>>> No, Fortran isn't C.
>>>>
>>>> if (bad) then
>>>>     SETERRQ(...)
>>>> endif
>>>>
>>>> It doesn't get used so much from Fortran that we need to conceal the
>>>> language constructs.
>>>
>>>   It will, eventually I want all Fortran examples/tests to have checks on every call (like with have in C).
>>
>> CHKERRQ does the if internally, so it also has the endif.
>
>   What is the relevance of this statement.
>>
>> SETERRA/SETERRQ is used a total of 34 times in 17 Fortran files.
>> SETERRQ is used a median of zero times and an average of less than 1 in
>> the C examples.
>
>    I am not sure why you are saying this. My resistance to change has nothing to do with how often it is used.
>
>    I am leaning to changing it but don't want to until all the test harness branches etc get into master. So it will be a few days.
>
>>
>>>>
>>>>>
>>>>>
>>>>>> This Fortran:
>>>>>>
>>>>>> #define SETERRQ(c,ierr,s)  ;call PetscError(c,ierr,0,s);return;endif
>>>>>>
>>>>>> This would be like writing this C
>>>>>>
>>>>>> #define SETERRQ(c,ierr,s) return PetscError(...); }
>>>>>>
>>>>>> to be used like
>>>>>>
>>>>>> if (BAD) { SETERRQ(comm, ierr, "why")
>>>>>>
>>>>>> which is just bananas and still not as gross as the Fortran.  You might
>>>>>> not have noticed this because SETERRQ is not called from any of PETSc's
>>>>>> Fortran examples.
>>>>>
>>>>>   But SETERRA() is and has the same pattern.
>>>>
>>>> It isn't syntactically correct when !defined(PETSC_USE_ERRORCHECKING).
>>>> The endif isn't going to kill anyone and pulling it out of the macro
>>>> will make it easier to understand and avoid the circus antics when used
>>>> in any context other than a positive conditional with no else clause.
>>>
>>>   I'll take this under advisement. Of course in our examples the endif will ALWAYS be on the same line as the rest. Using three lines for a SETERRQ() is ugly.
>>>
>>>
>>>>
>>>>>>
>>>>>>>> Beside not having unmatched if / end if in my code, in a select case construct, I have to write something as ugly as
>>>>>>>>
>>>>>>>> select case (i)
>>>>>>>>         case(1)
>>>>>>>>                 !do something
>>>>>>>>         case(2)
>>>>>>>>                 !do something else
>>>>>>>>         case default
>>>>>>>>                 if (0 == 0) then
>>>>>>>>                         SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_ARG_OUTOFRANG,”invalid value”)
>>>>>>>> end select
>>>>>>>>
>>>>>>> What is ugly about this ? except that you put the SETERRQ on a new line which you did not need to do.
>>>>>>
>>>>>> Reread the above code.  Requiring the dummy opening if statement is nuts.
>>>>>
>>>>>  Agreed. He should not use SETERRQ() in this case, should call the error functions directly)
>>>>>
>>>>>>
>>>>>>> How do you want to write it so it is prettier?
>>>>>>
>>>>>> SETERRQ should not include that endif.  CHKERRQ has the opening if and
>>>>>> thus needs the closing too (so it's as intended).  Also note that your
>>>>>> first reply to Blaise was talking about CHKERRQ when he was asking about
>>>>>> SETERRQ.
>>>>>
>>>>>   Hmm, I'm not sure about. Oh well, it doesn't matter. You have convinced me of anything.
>



-- 
Lisandro Dalcin
============
Research Scientist
Computer, Electrical and Mathematical Sciences & Engineering (CEMSE)
Extreme Computing Research Center (ECRC)
King Abdullah University of Science and Technology (KAUST)
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