|Description:||Returns integer data from a real-time clock. SYSTEM_CLOCK returns the number of seconds from 00:00 Coordinated Universal Time (CUT) on 1 JAN 1970. The number is returned with no bias. To get the elapsed time, you must call SYSTEM_CLOCK twice, and subtract the starting time value from the ending time value.|
|Arguments:||There are three optional arguments1:|
|COUNT (opt)||Must be scalar and of type default integer. It is set to a value based on the current value of the processor clock. The value is increased by one for each clock count until the value COUNT_MAX is reached, and is reset to zero at the next count. (COUNT lies in the range 0 to COUNT_MAX.)|
|COUNT_RATE (opt)||Must be scalar and
of type default integer. It is set to the number of processor clock
counts per second.
If default integer is INTEGER(2), COUNT_RATE is 1000. If default integer is INTEGER(4), COUNT_RATE is 10000. If default integer is INTEGER(8), COUNT_RATE is 1000000.
|COUNT_MAX (opt)||Must be scalar and of type default integer. It is set to the maximum value that COUNT can have, HUGE(0). For more information on HUGE, see Section 9.3.56.|
|1 All are INTENT(OUT) arguments. (See Section 5.10.)|
Consider the following:
integer(2) :: ic2, crate2, cmax2 integer(4) :: ic4, crate4, cmax4 call system_clock(count=ic2, count_rate=crate2, count_max=cmax2) call system_clock(count=ic4, count_rate=crate4, count_max=cmax4) print *, ic2, crate2, cmax2 print *, ic4, crate4, cmax4 end
This program was run on Thursday Dec 11, 1997 at 14:23:55 EST and produced the following output:
13880 1000 32767 1129498807 10000 2147483647