MPIFileiwriteat(3OpenMPI) MPIFileiwriteat(3OpenMPI)

NAME
       MMPPIIFFiilleeiiwwrriitteeaatt  -  Writes  a file at an explicitly specified offset
       (nonblocking, noncollective).


SSYYNNTTAAXX
       C Syntax
           #include 
           int MPIFileiwriteat(MPIFile fh, MPIOffset offset,
                  void *buf, int count, MPIDatatype datatype, MPIRequest *request)

       Fortran Syntax (see FORTRAN 77 NOTES)
           INCLUDE 'mpif.h'
           MPIFILEIWRITEAT(FH, OFFSET, BUF, COUNT, DATATYPE, REQUEST, IERROR)
                  BUF(*)
                 INTEGER   FH, COUNT, DATATYPE, REQUEST, IERROR
                 INTEGER(KIND=MPIOFFSETKIND) OFFSET


CC++++ SSyynnttaaxx
       #include 
       MPI::Request MPI::File::Iwriteat(MPI::Offset offset, const void* buf,
            int count, const MPI::Datatype& datatype)


IINNPPUUTT//OOUUTTPPUUTT PPAARRAAMMEETTEERR
       fh        File handle (handle).


IINNPPUUTT PPAARRAAMMEETTEERRSS
       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).


OOUUTTPPUUTT PPAARRAAMMEETTEERRSS
       request   Request object (handle).

       IERROR    Fortran only: Error status (integer).


DESCRIPTION
       MPIFileiwriteat is a nonblocking version  of  MPIFilewriteat.  It
       attempts to write into the file associated with fh (at the offset posi-
       tion) 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 cur-
       rent 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. MPIFileiwriteat stores the number of datatype  elements  actu-
       ally  written in status.  All other fields of status are undefined. The
       request structure can be passed to MPIWait  or  MPITest,  which  will
       return a status with the number of bytes actually accessed.

       It  is  erroneous  to call this function if MPIMODESEQENTIAL mode was
       specified when the file was open.


FFOORRTTRRAANN 7777 NNOOTTEESS
       The MPI standard prescribes portable  Fortran  syntax  for  the  OFFSET
       argument  only for Fortran 90.  FORTRAN 77 users may use the non-porta-
       ble syntax

            INTEGER*MPIOFFSETKIND OFFSET

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


EERRRROORRSS
       Almost  all MPI routines return an error value; C routines as the value
       of the function and Fortran routines in the last  argument.  C++  func-
       tions  do  not  return  errors.  If the default error handler is set to
       MPI::ERRORSTHROWEXCEPTIONS, 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   MPIERRORSRETURN.   The   error   handler  may  be  changed  with
       MPIFileseterrhandler;     the     predefined      error      handler
       MPIERRORSAREFATAL  may  be  used to make I/O errors fatal. Note that
       MPI does not guarantee that an MPI program can continue past an  error.




Open MPI 1.2                    September 2006    MPIFileiwriteat(3OpenMPI)