CPU_TIME — CPU elapsed time in seconds

Description

Returns a REAL value representing the elapsed CPU time in seconds. This is useful for testing segments of code to determine execution time.

If a time source is available, time will be reported with microsecond resolution. If no time source is available, TIME is set to -1.0.

Note that TIME may contain a, system dependent, arbitrary offset and may not start with 0.0. For CPU_TIME, the absolute value is meaningless, only differences between subsequent calls to this subroutine, as shown in the example below, should be used.

Syntax

CALL CPU_TIME(TIME)

Arguments

TIME The type shall be REAL with INTENT(OUT).

Return value

None

Example



program test_cpu_time

    real :: start, finish

    call cpu_time(start)

        ! put code to test here

    call cpu_time(finish)

    print '("Time = ",f6.3," seconds.")',finish-start

end program test_cpu_time

Standard

Fortran 95 and later

Class

Subroutine