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32 .Nd "Kernel pseudo-random number generators"
38 .Fn prng32_bounded "uint32_t bound"
42 .Fn prng64_bounded "uint64_t bound"
44 .Ss GENERIC PRNG ROUTINES
48 pseudo-random number generators.
56 avoid shared global state, removing unnecessary contention on SMP
58 The routines are not explicitly tied to any specific implementation, and
59 may produce different specific sequences on different hosts, reboots, or
62 Different CPUs in SMP systems are guaranteed to produce different sequences of
66 .Em cryptographically secure
67 random numbers generated by the
69 kernel cryptographically secure random number generator subsystem, see
72 .Bl -tag -width indent
74 Generate a 32-bit integer uniformly distributed in [0, 2^32-1].
75 .It Fn prng32_bounded bound
76 Generate an integer uniformly in the range [0, bound-1].
78 Generate a 64-bit integer uniformly distributed in [0, 2^64-1].
79 .It Fn prng64_bounded bound
80 Generate an integer uniformly in the range [0, bound-1].
83 These routines are not reentrant; they are not safe to use in interrupt
84 handlers ("interrupt filters" in
87 They are safe to use in all other kernel contexts, including interrupt threads
89 .Ss REPRODUCIBLE PRNG APIS
90 In addition to these per-CPU helpers, the
92 header also exposes the entire API of the PCG family of PRNGs as inline
94 The PCG-C API is described in full at
95 .Lk https://www.pcg-random.org/using-pcg-c.html .