# MPI_File_iwrite_at

Nonblocking write using explicit offset

## Synopsis

    #ifdef HAVE_MPI_GREQUEST
    #include "mpiu_greq.h"
    #endif

    int MPI_File_iwrite_at(MPI_File fh, MPI_Offset offset, ROMIO_CONST void *buf,
                           int count, MPI_Datatype datatype,
                           MPIO_Request *request)

## Input Parameters

fh
  file handle (handle)

offset
  file offset (nonnegative integer)

buf
  initial address of buffer (choice)

count
  number of elements in buffer (nonnegative integer)

datatype
  datatype of each buffer element (handle)

## Output Parameters

request
  request object (handle)

## Notes for Fortran

All MPI routines in Fortran (except for `MPI_WTIME` and `MPI_WTICK`) have an additional argument `ierr` at the end of the argument list. `ierr` is an integer and has the same meaning as the return value of the routine in C. In Fortran, MPI routines are subroutines, and are invoked with the `call` statement.

All MPI objects (e.g., `MPI_Datatype`, `MPI_Comm`) are of type `INTEGER` in Fortran.