CPU_TIME (time)

  Class:  Subroutine

  Returns a processor-dependent approximation of the processor time
  (in seconds).

  Argument "time" must be scalar and of real type.  It is an
  INTENT(OUT) argument.

  If a meaningful time cannot be returned, a processor-dependent
  negative value is returned.

  Example:

    REAL time_begin, time_end
    ...
    CALL CPU_TIME(time_begin)
    ...                         !some operation coding
    CALL CPU_TIME(time_end)
    PRINT (*,*) 'Time of operation was ', time_begin - time_end, ' seconds'