Is it easy to update *ompi_datatype_is_valid* to judge invalid datatypes, such as -1?
Dahai On Fri, Jun 2, 2017 at 9:00 AM, Gilles Gouaillardet < gilles.gouaillar...@gmail.com> wrote: > MPI_Datatype is a opaque handler, and -1 is a (signed) integer, so > what you are trying is very likely to have an undefined behavior per > the standard. > > if this seems to work with MPICH, this is not portable anyway, and > will very likely cause a crash with OpenMPI > > > Cheers, > > Gilles > > On Fri, Jun 2, 2017 at 10:41 PM, Dahai Guo <dahai....@gmail.com> wrote: > > 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 > _______________________________________________ > devel mailing list > devel@lists.open-mpi.org > https://rfd.newmexicoconsortium.org/mailman/listinfo/devel >
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