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)
- 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.