MPIPack(3OpenMPI) MPIPack(3OpenMPI)

NAME
       MMPPIIPPaacckk - Packs data of a given datatype into contiguous memory.


SSYYNNTTAAXX
CC SSyynnttaaxx
       #include 
       int MPIPack(void *inbuf, int incount, MPIDatatype datatype,
            void *outbuf, int outsize, int *position, MPIComm comm)


FFoorrttrraann SSyynnttaaxx
       INCLUDE 'mpif.h'
       MPIPACK(INBUF, INCOUNT, DATATYPE, OUTBUF,OUTSIZE, POSITION,
                 COMM, IERROR)
                INBUF(*), OUTBUF(*)
            INTEGER   INCOUNT, DATATYPE, OUTSIZE, POSITION, COMM, IERROR


CC++++ SSyynnttaaxx
       #include 
       void Datatype::Pack(const void* inbuf, int incount, void *outbuf,
            int outsize, int& position, const Comm &comm) const


IINNPPUUTT PPAARRAAMMEETTEERRSS
       inbuf     Input buffer start (choice).

       incount   Number of input data items (integer).

       datatype  Datatype of each input data item (handle).

       outsize   Output buffer size, in bytes (integer).

       comm      Communicator for packed message (handle).


IINNPPUUTT//OOUUTTPPUUTT PPAARRAAMMEETTEERR
       position  Current position in buffer, in bytes (integer).


OOUUTTPPUUTT PPAARRAAMMEETTEERRSS
       outbuf    Output buffer start (choice).

       IERROR    Fortran only: Error status (integer).


DESCRIPTION
       Packs  the  message  in  the  send  buffer specified by inbuf, incount,
       datatype into the buffer space specified by  outbuf  and  outsize.  The
       input  buffer  can be any communication buffer allowed in MPISend. The
       output buffer is a contiguous storage area  containing  outsize  bytes,
       starting  at  the  address outbuf (length is counted in bytes, not ele-
       ments, as if it were a communication  buffer  for  a  message  of  type
       MPIPacked).

       The  input value of position is the first location in the output buffer
       to be used for packing. position is incremented  by  the  size  of  the
       packed  message, and the output value of position is the first location
       in the output buffer following the locations  occupied  by  the  packed
       message.  The  comm  argument  is  the communicator that will be subse-
       quently used for sending the packed message.

       EExxaammppllee:: An example using MPIPack:

           int position, i, j, a[2];
           char buff[1000];

           ....

           MPICommrank(MPICOMMWORLD, &myrank);
           if (myrank == 0)
           {
              / * SENDER CODE */

           position = 0;
             MPIPack(&i, 1, MPIINT, buff, 1000, &position, MPICOMMWORLD);
             MPIPack(&j, 1, MPIINT, buff, 1000, &position, MPICOMMWORLD);
             MPISend( buff, position, MPIPACKED, 1, 0, MPICOMMWORLD);
           }
           else  /* RECEIVER CODE */
             MPIRecv( a, 2, MPIINT, 0, 0, MPICOMMWORLD)

           }


EERRRROORRSS
       Almost all MPI routines return an error value; C routines as the  value
       of  the  function  and Fortran routines in the last argument. C++ func-
       tions do not return errors. If the default  error  handler  is  set  to
       MPI::ERRORSTHROWEXCEPTIONS, then on error the C++ exception mechanism
       will be used to throw an MPI:Exception object.

       Before the error value is returned, the current MPI  error  handler  is
       called.  By  default, this error handler aborts the MPI job, except for
       I/O  function  errors.  The  error  handler   may   be   changed   with
       MPICommseterrhandler; the predefined error handler MPIERRORSRETURN
       may be used to cause error values to be returned. Note  that  MPI  does
       not guarantee that an MPI program can continue past an error.


SEE ALSO
       MPIUnpack
       MPIPacksize




Open MPI 1.2                    September 2006              MPIPack(3OpenMPI)