MPI_File_read_ordered(3OpenMPI) 										   MPI_File_read_ordered(3OpenMPI)

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
	   INCLUDE 'mpif.h'
	   MPI_FILE_READ_ORDERED(FH, BUF, COUNT, DATATYPE,
			 STATUS, IERROR)
		  <type>     BUF(*)
		  INTEGER    FH, COUNT, DATATYPE, STATUS(MPI_STATUS_SIZE), 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++ func-
       tions  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.

Open MPI 1.2							  September 2006				   MPI_File_read_ordered(3OpenMPI)