:ref:`MPI_File_iwrite_at` - Writes a file at an explicitly specified offset (nonblocking, noncollective).
#include <mpi.h>
int MPI_File_iwrite_at(MPI_File fh, MPI_Offset offset,
const void *buf, int count, MPI_Datatype datatype, MPI_Request *request)
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_FILE_IWRITE_AT(FH, OFFSET, BUF, COUNT, DATATYPE, REQUEST, IERROR)
<type> BUF(*)
INTEGER FH, COUNT, DATATYPE, REQUEST, IERROR
INTEGER(KIND=MPI_OFFSET_KIND) OFFSET
USE mpi_f08
MPI_File_iwrite_at(fh, offset, buf, count, datatype, request, ierror)
TYPE(MPI_File), INTENT(IN) :: fh
INTEGER(KIND=MPI_OFFSET_KIND), INTENT(IN) :: offset
TYPE(*), DIMENSION(..), INTENT(IN), ASYNCHRONOUS :: buf
INTEGER, INTENT(IN) :: count
TYPE(MPI_Datatype), INTENT(IN) :: datatype
TYPE(MPI_Request), INTENT(OUT) :: request
INTEGER, OPTIONAL, INTENT(OUT) :: ierror
fh
: File handle (handle).
offset
: File offset (integer).buf
: Initial address of buffer (choice).count
: Number of elements in buffer (integer).datatype
: Data type of each buffer element (handle).
request
: Request object (handle).ierror
: Fortran only: Error status (integer).
:ref:`MPI_File_iwrite_at` is a nonblocking version of :ref:`MPI_File_write_at`. It attempts to write into the file associated with fh (at the offset position) a total number of count data items having datatype type from the user's buffer buf. The offset is in etype units relative to the current view. That is, holes are not counted when locating an offset. The data is written into those parts of the file specified by the current view. :ref:`MPI_File_iwrite_at` stores the number of datatype elements actually written in status. All other fields of status are undefined. The request structure can be passed to :ref:`MPI_Wait` or :ref:`MPI_Test`, which will return a status with the number of bytes actually accessed.
It is erroneous to call this function if MPI_MODE_SEQUENTIAL mode was specified when the file was open.