so you are saying that a user should NOT define send/recv data type as -1,
in openmpi?
Dahai
On Thu, Jun 1, 2017 at 6:59 PM, Gilles Gouaillardet <gil...@rist.or.jp>
wrote:
> +1
>
>
> MPI_Datatype is an opaque handler, and in Open MPI, this is an
> ompi_datatype_t *
>
> so we can only test for NULL pointers or MPI_DATATYPE_NULL that cannot be
> used per the standard.
>
>
> fwiw, and iirc, MPICH made an other design choice and MPI_Datatype is a
> number, so the mpich equivalent of ompi_datatype_is_valid()
>
> might be able to handle random values without crashing.
>
>
> Cheers,
>
>
> Gilles
>
>
> On 6/2/2017 7:36 AM, George Bosilca wrote:
>
>> You have to pass it an allocated datatype, and it tells you if the
>> pointer object is a valid MPI datatype for communications (aka it has a
>> corresponding type with a well defined size, extent and alignment).
>>
>> There is no construct in C able to tell you if a random number if a valid
>> C "object".
>>
>> George.
>>
>>
>> On Thu, Jun 1, 2017 at 5:42 PM, Dahai Guo <dahai....@gmail.com <mailto:
>> dahai....@gmail.com>> wrote:
>>
>> Hi,
>>
>> if I insert following lines somewhere openmpi, such
>> as ompi/mpi/c/iscatter.c
>>
>> printf(" --- in MPI_Iscatter\n");
>> //MPI_Datatype dt00 = (MPI_Datatype) MPI_INT;
>> *MPI_Datatype dt00 = (MPI_Datatype) -1;*
>> if(*!ompi_datatype_is_valid(dt00)* ) {
>> printf(" --- dt00 is NOT valid \n");
>> }
>>
>> The attached test code will give the errors:
>>
>> *** Process received signal ***
>> Signal: Segmentation fault (11)
>> Signal code: Address not mapped (1)
>> Failing at address: 0xf
>> [ 0] [0x3fff9d480478]
>> ...
>>
>> Is it a bug in the function *ompi_datatype_is_valid(..) *? or I
>> miss something?
>>
>> Dahai
>>
>> _______________________________________________
>> devel mailing list
>> devel@lists.open-mpi.org <mailto:devel@lists.open-mpi.org>
>> https://rfd.newmexicoconsortium.org/mailman/listinfo/devel
>> <https://rfd.newmexicoconsortium.org/mailman/listinfo/devel>
>>
>>
>>
>>
>> _______________________________________________
>> devel mailing list
>> devel@lists.open-mpi.org
>> https://rfd.newmexicoconsortium.org/mailman/listinfo/devel
>>
>
> _______________________________________________
> devel mailing list
> devel@lists.open-mpi.org
> https://rfd.newmexicoconsortium.org/mailman/listinfo/devel
>
_______________________________________________
devel mailing list
devel@lists.open-mpi.org
https://rfd.newmexicoconsortium.org/mailman/listinfo/devel
