[mpiwg-tools] ticket 405: MPI_CHAR as string

Kathryn Mohror kathryn at llnl.gov
Sat Feb 15 19:46:29 CST 2014


Thanks again for the feedback. I have incorporated it and attached the latest version.

Kathryn

On Feb 15, 2014, at 4:47 AM, Marc-Andre Hermanns <m.a.hermanns at grs-sim.de> wrote:

> +1
> 
> I under stand the null-terminating character as "the character doing the
> null termination". As only the null character can do that, the text is
> clearer now.
> 
> Cheers,
> Marc-Andre
> 
> On 15.02.14 13:42, Jeff Squyres (jsquyres) wrote:
>> Sorry -- nit-picking on my own text:
>> 
>> -----
>> The use of the datatype MPI_CHAR in the MPI tool information interface implies a null-terminated character array, i.e., a string in the C language. If a variable has type MPI_CHAR, the value of the count parameter returned by MPI_T_CVAR_HANDLE_ALLOC and MPI_T_PVAR_HANDLE_ALLOC must be large enough to include any valid value, including its null-terminating character. The contents of returned MPI_CHAR arrays are only defined from index 0 through the location of the first null-terminating character.
>> -----
>> 
>> In the 2nd and 3rd sentence, we refer to the "null-terminating character".  Is that correct?  Isn't it just a "null character"?
>> 
>> We use "null-terminated character array" in the first sentence, and that seems fine. But "null-terminated character" means "a character terminated by a null", which doesn't seem to make sense.
>> 
>> In 14.3.3 ("Convention for Returning Strings"), we refer to the "null terminator" and "terminating null character").  
>> 
>> I therefore think we should slightly change the last 2 sentences to:
>> 
>> -----
>> The use of the datatype MPI_CHAR in the MPI tool information interface implies a null-terminated character array, i.e., a string in the C language. If a variable has type MPI_CHAR, the value of the count parameter returned by MPI_T_CVAR_HANDLE_ALLOC and MPI_T_PVAR_HANDLE_ALLOC must be large enough to include any valid value, including its ***terminating null*** character. The contents of returned MPI_CHAR arrays are only defined from index 0 through the location of the first ***null*** character.
>> -----
>> 
>> 
>> 
>> 
>> On Feb 14, 2014, at 6:16 PM, "Mohror, Kathryn" <mohror1 at llnl.gov> wrote:
>> 
>>> Thanks for the feedback. I have attached a new draft for this ticket and incorporated your changes. Please give me any additional comments by the start of business Monday.
>>> 
>>> Kathryn
>>> 
>>> On Feb 14, 2014, at 7:23 AM, Dave Goodell (dgoodell) <dgoodell at cisco.com> wrote:
>>> 
>>>> +1 to almost everything that Jeff said.  My only quibble would be to change the last sentence in his text from:
>>>> 
>>>> The contents of returned MPI_CHAR values are only defined from index 0 through the location of the first null-terminating character.
>>>> 
>>>> To:
>>>> 
>>>> The contents of returned MPI_CHAR ***arrays*** are only defined from index 0 through the location of the first null-terminating character.
>>>> 
>>>> -Dave
>>>> 
>>>> On Feb 14, 2014, at 7:27 AM, Jeff Squyres (jsquyres) <jsquyres at cisco.com> wrote:
>>>> 
>>>>> Here's the new text:
>>>>> 
>>>>> -----
>>>>> The use of the datatype MPI_CHAR in the MPI tool information interface implies a null-terminated character array, i.e. a string in the C language. If a variable has type MPI_CHAR, the value of the count parameter returned by MPI_T_CVAR_HANDLE_ALLOC and MPI_T_PVAR_HANDLE_ALLOC will include the null-terminating character. The value returned in count must be large enough to contain any valid value for the given variable. Arrays of type MPI_CHAR are only valid to the first null character.
>>>>> -----
>>>>> 
>>>>> There's a missing "," after "i.e." -- it should be "i.e.,"
>>>>> 
>>>>> I'd make some other minor changes:
>>>>> 
>>>>> The use of the datatype MPI_CHAR in the MPI tool information interface implies a null-terminated character array, i.e., a string in the C language. If a variable has type MPI_CHAR, the value of the count parameter returned by MPI_T_CVAR_HANDLE_ALLOC and MPI_T_PVAR_HANDLE_ALLOC ***must be large enough to include any valid value, including its null-terminating character.***  ***The contents of returned MPI_CHAR values are only defined from index 0 through the location of the first null-terminating character.***
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> On Feb 13, 2014, at 3:24 PM, Kathryn Mohror <kathryn at llnl.gov> wrote:
>>>>> 
>>>>>> Hi all,
>>>>>> 
>>>>>> Please have a look at this since we  have to decide if it's ready for a reading, and submit it to the forum for review on Monday if we do.
>>>>>> 
>>>>>> Kathryn
>>>>>> 
>>>>>> On Feb 7, 2014, at 1:05 PM, "Mohror, Kathryn" <mohror1 at llnl.gov> wrote:
>>>>>> 
>>>>>>> Hi all,
>>>>>>> 
>>>>>>> As we discussed in our call, I have drafted new text for ticket 405 which clarifies our intent for the MPI_CHAR datatype to represent strings in the tools interface. Please take a look at the red text for ticket 405 in the attached document and send your comments.
>>>>>>> 
>>>>>>> Kathryn
>>>>>>> 
>>>>>>> 
>>>>>>> _________________________________________________________________
>>>>>>> Kathryn Mohror, kathryn at llnl.gov, http://scalability.llnl.gov/
>>>>>>> Scalability Team @ Lawrence Livermore National Laboratory, Livermore, CA, USA
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> 
>>>>>>> <tools-3.pdf>_______________________________________________
>>>>>>> mpiwg-tools mailing list
>>>>>>> mpiwg-tools at lists.mpi-forum.org
>>>>>>> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-tools
>>>>>> 
>>>>>> _________________________________________________________________
>>>>>> Kathryn Mohror, kathryn at llnl.gov, http://scalability.llnl.gov/
>>>>>> Scalability Team @ Lawrence Livermore National Laboratory, Livermore, CA, USA
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> 
>>>>>> _______________________________________________
>>>>>> mpiwg-tools mailing list
>>>>>> mpiwg-tools at lists.mpi-forum.org
>>>>>> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-tools
>>>>> 
>>>>> 
>>>>> -- 
>>>>> Jeff Squyres
>>>>> jsquyres at cisco.com
>>>>> For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/
>>>>> 
>>>>> _______________________________________________
>>>>> mpiwg-tools mailing list
>>>>> mpiwg-tools at lists.mpi-forum.org
>>>>> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-tools
>>>> 
>>>> _______________________________________________
>>>> mpiwg-tools mailing list
>>>> mpiwg-tools at lists.mpi-forum.org
>>>> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-tools
>>> 
>>> _________________________________________________________________
>>> Kathryn Mohror, kathryn at llnl.gov, http://scalability.llnl.gov/
>>> Scalability Team @ Lawrence Livermore National Laboratory, Livermore, CA, USA
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> <tools-3.pdf>_______________________________________________
>>> mpiwg-tools mailing list
>>> mpiwg-tools at lists.mpi-forum.org
>>> http://lists.mpi-forum.org/mailman/listinfo.cgi/mpiwg-tools
>> 
>> 
> 
> -- 
> Marc-Andre Hermanns
> German Research School for
> Simulation Sciences GmbH
> c/o Laboratory for Parallel Programming
> 52062 Aachen | Germany
> 
> Tel +49 241 80 99753
> Fax +49 241 80 6 99753
> Web www.grs-sim.de
> 
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_________________________________________________________________
Kathryn Mohror, kathryn at llnl.gov, http://scalability.llnl.gov/
Scalability Team @ Lawrence Livermore National Laboratory, Livermore, CA, USA








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