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)
- 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.