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.. _mpi_file_iread:
MPI_File_iread
==============
.. include_body
:ref:`MPI_File_iread` |mdash| Reads a file starting at the location specified by
the individual file pointer (nonblocking, noncollective).
SYNTAX
------
C Syntax
^^^^^^^^
.. code-block:: c
#include <mpi.h>
int MPI_File_iread(MPI_File fh, void *buf, int count,
MPI_Datatype datatype, MPI_Request *request)
Fortran Syntax
^^^^^^^^^^^^^^
.. code-block:: fortran
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_FILE_IREAD(FH, BUF, COUNT, DATATYPE, REQUEST, IERROR)
<type> BUF(*)
INTEGER FH, COUNT, DATATYPE, REQUEST, IERROR
Fortran 2008 Syntax
^^^^^^^^^^^^^^^^^^^
.. code-block:: fortran
USE mpi_f08
MPI_File_iread(fh, buf, count, datatype, request, ierror)
TYPE(MPI_File), INTENT(IN) :: fh
TYPE(*), DIMENSION(..), ASYNCHRONOUS :: buf
INTEGER, INTENT(IN) :: count
TYPE(MPI_Datatype), INTENT(IN) :: datatype
TYPE(MPI_Request), INTENT(OUT) :: request
INTEGER, OPTIONAL, INTENT(OUT) :: ierror
INPUT/OUTPUT PARAMETER
----------------------
* ``fh``: File handle (handle).
INPUT PARAMETERS
----------------
* ``count``: Number of elements in the buffer (integer).
* ``datatype``: Data type of each buffer element (handle).
OUTPUT PARAMETERS
-----------------
* ``buf``: Initial address of buffer (choice).
* ``request``: Request object (handle).
* ``ierror``: Fortran only: Error status (integer).
DESCRIPTION
-----------
:ref:`MPI_File_iread` is a nonblocking version of :ref:`MPI_File_read`. It attempts to
read from the file associated with *fh* at the current individual file
pointer position maintained by the system in which a total number of
*count* data items having *datatype* type are read into the user's
buffer *buf.* The data is taken out of those parts of the file specified
by the current view. :ref:`MPI_File_iread` stores the number of data-type
elements actually read in *status.* All other fields of *status* are
undefined. It is erroneous to call this function if ``MPI_MODE_SEQUENTIAL``
mode was specified when the file was opened.
ERRORS
------
.. include:: ./ERRORS.rst
|
