NAME

       MPI_File_iwrite_at_all - Writes a file at an explicitly specified offset (nonblocking, collective).

SYNTAX

C Syntax

       #include <mpi.h>
       int MPI_File_iwrite_at_all(MPI_File fh, MPI_Offset offset,
            const void *buf, int count, MPI_Datatype datatype, MPI_Request *request)

Fortran Syntax (see FORTRAN 77 NOTES)

       USE MPI
       ! or the older form: INCLUDE 'mpif.h'
       MPI_FILE_IWRITE_AT_ALL(FH, OFFSET, BUF, COUNT, DATATYPE, REQUEST, IERROR)
            <type>    BUF(*)
            INTEGER   FH, COUNT, DATATYPE, REQUEST, IERROR
            INTEGER(KIND=MPI_OFFSET_KIND) OFFSET

Fortran 2008 Syntax

       USE mpi_f08
       MPI_File_iwrite_at_all(fh, offset, buf, count, datatype, request, ierror)
            TYPE(MPI_File), INTENT(IN) :: fh
            INTEGER(KIND=MPI_OFFSET_KIND), INTENT(IN) :: offset
            TYPE(*), DIMENSION(..) :: 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

       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).

OUTPUT PARAMETERS

       request   Request object (handle).

       IERROR    Fortran only: Error status (integer).

DESCRIPTION

       MPI_File_iwrite_at_all  is  a nonblocking version of MPI_File_write_at_all. 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.  MPI_File_iwrite_at_all  stores  the  number of datatype elements actually written in
       status.  All other fields of status are undefined. The request structure can be  passed  to  MPI_Wait  or
       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.

FORTRAN 77 NOTES

       The MPI standard prescribes portable Fortran syntax for the OFFSET argument only for Fortran 90.  FORTRAN
       77 users may use the non-portable syntax

            INTEGER*MPI_OFFSET_KIND OFFSET

       where MPI_OFFSET_KIND is a constant defined in mpif.h and gives the length of  the  declared  integer  in
       bytes.

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.