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)

       USE MPI
       ! or the older form: INCLUDE 'mpif.h'
       MPI_FILE_SET_SIZE(FH, SIZE, IERROR)
            INTEGER   FH, IERROR
            INTEGER(KIND=MPI_OFFSET_KIND) SIZE

Fortran 2008 Syntax

       USE mpi_f08
       MPI_File_set_size(fh, size, ierror)
            TYPE(MPI_File), INTENT(IN) :: fh
            INTEGER(KIND=MPI_OFFSET_KIND), INTENT(IN) :: size
            INTEGER, OPTIONAL, INTENT(OUT) :: ierror

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
       necessary. 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  position
       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.  FORTRAN
       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.