oracular (3) MPI_File_read_ordered.openmpi.3.gz

NAME

       MPI_File_read_ordered  -  Reads  a  file  at  a  location  specified  by a shared file pointer (blocking,
       collective).

SYNTAX

C Syntax

       #include <mpi.h>
       int MPI_File_read_ordered(MPI_File fh, void *buf,
            int count, MPI_Datatype datatype,
            MPI_Status *status)

Fortran Syntax

       USE MPI
       ! or the older form: INCLUDE 'mpif.h'
       MPI_FILE_READ_ORDERED(FH, BUF, COUNT, DATATYPE,
            STATUS, IERROR)
            <type>    BUF(*)
            INTEGER   FH, COUNT, DATATYPE, STATUS(MPI_STATUS_SIZE), IERROR

Fortran 2008 Syntax

       USE mpi_f08
       MPI_File_read_ordered(fh, buf, count, datatype, status, ierror)
            TYPE(MPI_File), INTENT(IN) :: fh
            TYPE(*), DIMENSION(..) :: buf
            INTEGER, INTENT(IN) :: count
            TYPE(MPI_Datatype), INTENT(IN) :: datatype
            TYPE(MPI_Status) :: status
            INTEGER, OPTIONAL, INTENT(OUT) :: ierror

C++ Syntax

       #include <mpi.h>
       void MPI::File::Read_ordered(void* buf, int count,
            const MPI::Datatype& datatype, MPI::Status& status)

       void MPI::File::Read_ordered(void* buf, int count,
            const MPI::Datatype& datatype)

INPUT PARAMETERS

       fh        File handle (handle).

       count     Number of elements in buffer (integer).

       datatype  Data type of each buffer element (handle).

OUTPUT PARAMETERS

       buf       Initial address of buffer (choice).

       status    Status object (Status).

       IERROR    Fortran only: Error status (integer).

DESCRIPTION

       MPI_File_read_ordered is a collective routine. This routine must  be  called  by  all  processes  in  the
       communicator  group  associated with the file handle fh.  Each process may pass different argument values
       for the datatype and count arguments. Each process attempts to read, from the file associated with fh,  a
       total  number of count data items having datatype type into the user's buffer buf.  For each process, the
       location in the file at which data is read is the position at which the  shared  file  pointer  would  be
       after  all processes whose ranks within the group are less than that of this process had read their data.
       MPI_File_read_ordered returns the actual number of datatype elements read in  status.   The  shared  file
       pointer is updated by the amounts of data requested by all processes of the group.

ERRORS

       Almost  all  MPI  routines  return  an  error  value; C routines as the value of the function and Fortran
       routines in the last argument. C++ functions do not return errors. If the default error handler is set to
       MPI::ERRORS_THROW_EXCEPTIONS,  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. For MPI I/O function errors,
       the  default  error  handler  is  set  to  MPI_ERRORS_RETURN.  The  error  handler  may  be  changed with
       MPI_File_set_errhandler; the predefined error handler MPI_ERRORS_ARE_FATAL may be used to make I/O errors
       fatal. Note that MPI does not guarantee that an MPI program can continue past an error.