gcc/fortran/doc/gfortran/intrinsic-procedures/cputime.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:: CPU_TIME, time, elapsed
   7
   8 .. _cpu_time:
   9
  10 CPU_TIME --- CPU elapsed time in seconds
  11 ****************************************
  12
  13 .. function:: CPU_TIME(TIME)
  14
  15   Returns a ``REAL`` value representing the elapsed CPU time in
  16   seconds.  This is useful for testing segments of code to determine
  17   execution time.
  18
  19   :param TIME:
  20     The type shall be ``REAL`` with ``INTENT(OUT)``.
  21
  22   :return:
  23     None
  24
  25   Standard:
  26     Fortran 95 and later
  27
  28   Class:
  29     Subroutine
  30
  31   Syntax:
  32     .. code-block:: fortran
  33
  34       CALL CPU_TIME(TIME)
  35
  36   Example:
  37     .. code-block:: fortran
  38
  39       program test_cpu_time
  40           real :: start, finish
  41           call cpu_time(start)
  42               ! put code to test here
  43           call cpu_time(finish)
  44           print '("Time = ",f6.3," seconds.")',finish-start
  45       end program test_cpu_time
  46
  47   See also:
  48     :ref:`SYSTEM_CLOCK`,
  49     :ref:`DATE_AND_TIME`