NAME

       MPI_File_write_at - Writes a file at an explicitly specified offset (blocking, noncollective).

SYNTAX

C Syntax

       #include  <mpi.h>  int MPI_File_write_at(MPI_File fh, MPI_Offset offset, const void *buf,      int count,
       MPI_Datatype datatype, MPI_Status *status)

Fortran Syntax (see FORTRAN 77 NOTES)

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

C++ Syntax

       #include <mpi.h>
       void MPI::File::Write_at(MPI::Offset offset, const void* buf,
            int count, const MPI::Datatype& datatype, MPI::Status& status)

       void MPI::File::Write_at(MPI::Offset offset, const void* buf,
            int count, const MPI::Datatype& datatype)

INPUT PARAMETERS

       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).

OUTPUT PARAMETERS

       status    Status object (status).

       IERROR    Fortran only: Error status (integer).

DESCRIPTION

       MPI_File_write_at 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_write_at stores the number of
       datatype elements actually written 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.

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.

SEE ALSO

       MPI_File_iwrite_at
       MPI_File_write_at_all
       MPI_File_write_at_all_begin
       MPI_File_write_at_all_end