MPI_File_set_size(3)               Open MPI               MPI_File_set_size(3)



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 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.





1.4.1                            Jan 14, 2010             MPI_File_set_size(3)
