fseek

Date:: 09-23-2013

NAME

fseek, ftell - Reposition a stream (C) or logical unit (FTN).

SYNOPSIS

C Synopsis

#include <stdio.h>

int fseek(FILE *stream, long offset, int whence);

long ftell(FILE *stream)

Fortran Synopsis

integer unit
integer offset
integer whence

integer function fseek(unit, offset, whence)

integer funtion ftell(unit)

IMPLEMENTATION

Cray Linux Environment (CLE)

DESCRIPTION

fseek sets the file position. The new position, measured in bytes, is obtained by adding offset bytes to the position specified by whence. If whence is set to either 0, 1, or 2, the offset is relative to either the start of the file, the current position indicator, or end-of-file, respectively. On success, returns 0; otherwise, system error.

ftell returns the current value of the file position indicator for the file (or unit) which is an offset, in bytes, from the beginning of the file.

EXAMPLE

PROGRAM test_fseek
            INTEGER, PARAMETER :: SEEK_SET = 0, SEEK_CUR = 1, SEEK_END = 2
            INTEGER :: fd, offset, ierr

            ierr   = 0
            offset = 5
            fd     = 10

            OPEN(UNIT=fd, FILE="fseek.test")
            ierr = FSEEK(fd, offset, SEEK_SET)  ! move to OFFSET
            print *, FTELL(fd), ierr

            ierr = FSEEK(fd, 0, SEEK_END)       ! move to end
            print *, FTELL(fd), ierr

            ierr =  FSEEK(fd, 0, SEEK_SET)      ! move to beginning
            print *, FTELL(fd), ierr

            CLOSE(UNIT=fd)
END PROGRAM