MCLOCK8 — Time function (64-bit)
clock(3) in the C standard library.
Warning: this intrinsic does not increase the range of the timing
values over that returned by clock(3). On a system with a 32-bit
clock(3), MCLOCK8 will return a 32-bit value, even though
it is converted to a 64-bit INTEGER(8) value. That means
overflows of the 32-bit value can still occur. 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.
RESULT = MCLOCK8()
INTEGER(8), equal to the
number of clock ticks since the start of the process, or -1 if
the system does not support clock(3).