gcc/fortran/doc/gfortran/intrinsic-procedures/ftell.rst

   1 ..
   2   Copyright 1988-2022 Free Software Foundation, Inc.
   3   This is part of the GCC manual.
   4   For copying conditions, see the copyright.rst file.
   5
   6 .. index:: FTELL, file operation, position
   7
   8 .. _ftell:
   9
  10 FTELL --- Current stream position
  11 *********************************
  12
  13 .. function:: FTELL(UNIT)
  14
  15   Retrieves the current position within an open file.
  16
  17   :param OFFSET:
  18     Shall of type ``INTEGER``.
  19
  20   :param UNIT:
  21     Shall of type ``INTEGER``.
  22
  23   :return:
  24     In either syntax, :samp:`{OFFSET}` is set to the current offset of unit
  25     number :samp:`{UNIT}`, or to -1 if the unit is not currently open.
  26
  27   Standard:
  28     GNU extension
  29
  30   Class:
  31     Subroutine, function
  32
  33   Syntax:
  34     .. code-block:: fortran
  35
  36       CALL FTELL(UNIT, OFFSET)
  37       OFFSET = FTELL(UNIT)
  38
  39   Example:
  40     .. code-block:: fortran
  41
  42       PROGRAM test_ftell
  43         INTEGER :: i
  44         OPEN(10, FILE="temp.dat")
  45         CALL ftell(10,i)
  46         WRITE(*,*) i
  47       END PROGRAM
  48
  49   See also:
  50     :ref:`FSEEK`