prng
is a family of fast,
non-cryptographic
pseudo-random number generators.
Unlike
random(9),
prng32(),
prng32_bounded(),
prng64(),
and
prng64_bounded()
avoid shared global state, removing unnecessary contention on SMP
systems.
The routines are not explicitly tied to any specific implementation, and
may produce different specific sequences on different hosts, reboots, or
versions of
FreeBSD .
Different CPUs in SMP systems are guaranteed to produce different sequences of
integers.
For
cryptographically secure
random numbers generated by the
random(4)
kernel cryptographically secure random number generator subsystem, see
arc4random(9).
|
| prng32()
|
| |
Generate a 32-bit integer uniformly distributed in [0, 2^32-1].
|
| prng32_bounded(bound)
|
| |
Generate an integer uniformly in the range [0, bound-1].
|
| prng64()
|
| |
Generate a 64-bit integer uniformly distributed in [0, 2^64-1].
|
| prng64_bounded(bound)
|
| |
Generate an integer uniformly in the range [0, bound-1].
|
|
These routines are not reentrant; they are not safe to use in interrupt
handlers ("interrupt filters" in
bus_setup_intr(9)
terminology).
They are safe to use in all other kernel contexts, including interrupt threads
("ithreads").
