9.98 ETIME — Execution time subroutine (or function)

Description:

ETIME(VALUES, TIME) returns the number of seconds of runtime since the start of the process’s execution in TIME. VALUES returns the user and system components of this time in VALUES(1) and VALUES(2) respectively. TIME is equal to VALUES(1) + VALUES(2).

On some systems, the underlying timings are represented using types with sufficiently small limits that overflows (wrap around) are possible, such as 32-bit types. Therefore, the values returned by this intrinsic might be, or become, negative, or numerically less than previous values, during a single run of the compiled program.

This intrinsic is provided in both subroutine and function forms; however, only one form can be used in any given program unit.

VALUES and TIME are INTENT(OUT) and provide the following:

	VALUES(1):	User time in seconds.
	VALUES(2):	System time in seconds.
	TIME:	Run time since start in seconds.

Standard:

GNU extension

Class:

Subroutine, function

Syntax:

CALL ETIME(VALUES, TIME).

TIME = ETIME(VALUES), (not recommended).

Arguments:

VALUES	The type shall be REAL(4), DIMENSION(2).
TIME	The type shall be REAL(4).

Return value:

Elapsed time in seconds since the start of program execution.

Example:

program test_etime
    integer(8) :: i, j
    real, dimension(2) :: tarray
    real :: result
    call ETIME(tarray, result)
    print *, result
    print *, tarray(1)
    print *, tarray(2)   
    do i=1,100000000    ! Just a delay
        j = i * i - i
    end do
    call ETIME(tarray, result)
    print *, result
    print *, tarray(1)
    print *, tarray(2)
end program test_etime

See also:

CPU_TIME