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MPI_File_set_size(3OpenMPI)                                                      MPI_File_set_size(3OpenMPI)



NAME
       MPI_File_set_size - Resizes a file (collective).


SYNTAX
       C Syntax
           #include <mpi.h>
           int MPI_File_set_size(MPI_File fh, MPI_Offset size)

       Fortran Syntax (see FORTRAN 77 NOTES)
           INCLUDE 'mpif.h'
           MPI_FILE_SET_SIZE(FH, SIZE,  IERROR)
                  INTEGER FH, IERROR
                  INTEGER(KIND=MPI_OFFSET_KIND) SIZE


C++ Syntax
       #include <mpi.h>
       void MPI::File::Set_size(MPI::Offset size)


INPUT PARAMETERS
       fh        File handle (handle).

       size      Size to truncate or expand file (integer).


OUTPUT PARAMETER
       IERROR    Fortran only: Error status (integer).


DESCRIPTION
       MPI_File_set_size  resizes the file associated with the file handle fh, truncating UNIX files as nec-essary. necessary.
       essary. MPI_File_set_size is collective; all processes in the group must pass  identical  values  for
       size.

       When  using  MPI_File_set_size on a UNIX file, if size is larger than the current file size, the file
       size becomes size. If size is smaller than the current file size, the file is truncated at the  posi-tion position
       tion  defined  by  size  (from  the beginning of the file and measured in bytes). Regions of the file
       which have been previously written are unaffected.

       MPI_File_set_size does not affect the individual file pointers or the shared file pointer.

       Note that the  actual  amount  of  storage  space  cannot  be  allocated  by  MPI_File_set_size.  Use
       MPI_File_preallocate to accomplish this.

       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 SIZE argument only for Fortran 90.   FOR-TRAN FORTRAN
       TRAN 77 users may use the non-portable syntax

            INTEGER*MPI_OFFSET_KIND SIZE

       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.





Open MPI 1.2                                   September 2006                    MPI_File_set_size(3OpenMPI)