NAME

       MPI_Sendrecv -  Sends and receives a message

SYNOPSIS

       int MPI_Sendrecv(const void *sendbuf, int sendcount, MPI_Datatype sendtype,
                       int dest, int sendtag,
                       void *recvbuf, int recvcount, MPI_Datatype recvtype,
                       int source, int recvtag,
                       MPI_Comm comm, MPI_Status *status)

INPUT PARAMETERS

       sendbuf
              - initial address of send buffer (choice)
       sendcount
              - number of elements in send buffer (integer)
       sendtype
              - type of elements in send buffer (handle)
       dest   - rank of destination (integer)
       sendtag
              - send tag (integer)
       recvcount
              - number of elements in receive buffer (integer)
       recvtype
              - type of elements in receive buffer (handle)
       source - rank of source (integer)
       recvtag
              - receive tag (integer)
       comm   - communicator (handle)

OUTPUT PARAMETERS

       recvbuf
              - initial address of receive buffer (choice)
       status - status object (Status).  This refers to the receive operation.

THREAD AND INTERRUPT SAFETY

       This  routine is thread-safe.  This means that this routine may be safely used by multiple
       threads without the need for any user-provided thread locks.  However, the routine is  not
       interrupt  safe.   Typically, this is due to the use of memory allocation routines such as
       malloc or other non-MPICH runtime routines that are themselves not interrupt-safe.

NOTES FOR FORTRAN

       All MPI routines in Fortran (except for MPI_WTIME  and  MPI_WTICK  )  have  an  additional
       argument  ierr  at  the  end  of  the  argument list.  ierr is an integer and has the same
       meaning as the  return  value  of  the  routine  in  C.   In  Fortran,  MPI  routines  are
       subroutines, and are invoked with the call statement.

       All MPI objects (e.g., MPI_Datatype , MPI_Comm ) are of type INTEGER in Fortran.

       The  status  argument must be declared as an array of size MPI_STATUS_SIZE , as in integer
       status(MPI_STATUS_SIZE) .

ERRORS

       All MPI routines (except MPI_Wtime and MPI_Wtick ) return an error value;  C  routines  as
       the  value of the function and Fortran routines in the last argument.  Before the value is
       returned, the current MPI error handler is called.  By default, this error handler  aborts
       the  MPI  job.   The  error  handler  may  be  changed  with  MPI_Comm_set_errhandler (for
       communicators), MPI_File_set_errhandler (for files), and MPI_Win_set_errhandler  (for  RMA
       windows).   The  MPI-1  routine  MPI_Errhandler_set may be used but its use is deprecated.
       The predefined error handler MPI_ERRORS_RETURN may be used to cause  error  values  to  be
       returned.   Note  that  MPI  does  not  guarentee that an MPI program can continue past an
       error; however, MPI implementations will attempt to continue whenever possible.

       MPI_SUCCESS
              - No error; MPI routine completed successfully.
       MPI_ERR_COMM
              - Invalid communicator.  A common error is to use a null  communicator  in  a  call
              (not even allowed in MPI_Comm_rank ).
       MPI_ERR_COUNT
              - Invalid count argument.  Count arguments must be non-negative; a count of zero is
              often valid.
       MPI_ERR_TYPE
              - Invalid datatype argument.  Additionally, this error can occur if an  uncommitted
              MPI_Datatype (see MPI_Type_commit ) is used in a communication call.
       MPI_ERR_TAG
              -  Invalid tag argument.  Tags must be non-negative; tags in a receive ( MPI_Recv ,
              MPI_Irecv , MPI_Sendrecv , etc.) may also be MPI_ANY_TAG .  The largest  tag  value
              is available through the the attribute MPI_TAG_UB .

       MPI_ERR_RANK
              -  Invalid  source or destination rank.  Ranks must be between zero and the size of
              the  communicator  minus  one;  ranks  in  a  receive  (  MPI_Recv  ,  MPI_Irecv  ,
              MPI_Sendrecv , etc.) may also be MPI_ANY_SOURCE .

                                            11/12/2016                            MPI_Sendrecv(3)