secnds: Get System Time in Seconds, Minus Argument

Example: secnds:

demo% cat sec1.f 
    real elapsed, t0, t1, x, y 
    t0 = 0.0 
    t1 = secnds( t0 ) 
    y = 0.1 
    do i = 1, 1000 
        x = asin( y ) 
    end do 
    elapsed = secnds( t1 ) 
    write ( *, 1 ) elapsed 
1    format ( ' 1000 arcsines: ', f12.6, ' sec' ) 
    end 
demo% f77 -silent sec1.f
demo% a.out 
 1000 arcsines: 6.699141 sec 
demo% 

Note that:

• The returned value from SECNDS is accurate to 0.01 second.

• The value is the system time, as the number of seconds from midnight, and it correctly spans midnight.

• Some precision may be lost for small time intervals near the end of the day.