gcc/fortran/doc/gfortran/intrinsic-procedures/etime.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:: ETIME, time, elapsed
   7
   8 .. _etime:
   9
  10 ETIME --- Execution time subroutine (or function)
  11 *************************************************
  12
  13 .. function:: ETIME(VALUES, TIME)
  14
  15   ``ETIME(VALUES, TIME)`` returns the number of seconds of runtime
  16   since the start of the process's execution in :samp:`{TIME}`.  :samp:`{VALUES}`
  17   returns the user and system components of this time in ``VALUES(1)`` and
  18   ``VALUES(2)`` respectively. :samp:`{TIME}` is equal to ``VALUES(1) + VALUES(2)``.
  19
  20   :param VALUES:
  21     The type shall be ``REAL(4), DIMENSION(2)``.
  22
  23   :param TIME:
  24     The type shall be ``REAL(4)``.
  25
  26   :return:
  27     Elapsed time in seconds since the start of program execution.
  28
  29   Standard:
  30     GNU extension
  31
  32   Class:
  33     Subroutine, function
  34
  35   Syntax:
  36     .. code-block:: fortran
  37
  38       CALL ETIME(VALUES, TIME).
  39       TIME = ETIME(VALUES), (not recommended).
  40
  41   Example:
  42     .. code-block:: fortran
  43
  44       program test_etime
  45           integer(8) :: i, j
  46           real, dimension(2) :: tarray
  47           real :: result
  48           call ETIME(tarray, result)
  49           print *, result
  50           print *, tarray(1)
  51           print *, tarray(2)
  52           do i=1,100000000    ! Just a delay
  53               j = i * i - i
  54           end do
  55           call ETIME(tarray, result)
  56           print *, result
  57           print *, tarray(1)
  58           print *, tarray(2)
  59       end program test_etime
  60
  61   See also:
  62     :ref:`CPU_TIME`