MPI_File_seek_shared(3) man page (version 4.1.8)

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Name

MPI_File_seek_shared - Updates the global shared file pointer (collective).

Syntax

C Syntax
#include <mpi.h>
int MPI_File_seek_shared(MPI_File fh, MPI_Offset offset,
 int whence)

Fortran Syntax (see FORTRAN 77 NOTES)

USE MPI
! or the older form: INCLUDE ’mpif.h’
MPI_FILE_SEEK_SHARED(FH, OFFSET, WHENCE, IERROR)
 INTEGER FH, WHENCE, IERROR
 INTEGER(KIND=MPI_OFFSET_KIND) OFFSET

Fortran 2008 Syntax

USE mpi_f08
MPI_File_seek_shared(fh, offset, whence, ierror)
 TYPE(MPI_File), INTENT(IN) :: fh
 INTEGER(KIND=MPI_OFFSET_KIND), INTENT(IN) :: offset
 INTEGER, INTENT(IN) :: whence
 INTEGER, OPTIONAL, INTENT(OUT) :: ierror

Input Parameters

fh

File handle (handle).

offset

File offset (integer).

whence

Update mode (integer).

Output Parameter

IERROR

Fortran only: Error status (integer).

Description

MPI_File_seek_shared updates the shared file pointer according to whence, which could have the following possible values:

o

MPI_SEEK_SET - The pointer is set to offset.

o

MPI_SEEK_CUR - The pointer is set to the current pointer position plus offset.

o

MPI_SEEK_END - The pointer is set to the end of the file plus offset.

MPI_File_seek_shared is collective; all the processes in the communicator group associated with the file handle fh must call MPI_File_seek_shared with the same offset and whence. All processes in the communicator group are synchronized before the shared file pointer is updated.

The offset can be negative, which allows seeking backwards. It is erroneous to seek to a negative position in the view. The end of the view is defined to be the position of the next elementary data item, relative to the current view, following the last whole elementary data item accessible.

Fortran 77 Notes

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

 INTEGER*MPI_OFFSET_KIND OFFSET

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.

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Table of Contents

• Name
• Syntax
• C Syntax
• Fortran Syntax (see FORTRAN 77 NOTES)
• Fortran 2008 Syntax
• Input Parameters
• Output Parameter
• Description
• Fortran 77 Notes
• Errors

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Page last modified: 5-Feb-2025
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