BSD::ARC4RANDOM - reference manual online

Perl interface to the arc4 random number generator.

BSD::arc4random(3pm)           User Contributed Perl Documentation           BSD::arc4random(3pm)

NAME BSD::arc4random - Perl interface to the arc4 random number generator
SYNOPSIS use BSD::arc4random qw(:all); $v = arc4random(); $v = arc4random_uniform($hz); if (!BSD::arc4random::have_kintf()) { $v = arc4random_addrandom("entropy to pass to the system"); } else { $v = arc4random_pushb("entropy to pass to the system"); $v = arc4random_pushk("entropy to pass to the kernel"); } $s = arc4random_bytes(16, "entropy to pass to libc"); arc4random_stir(); $s = arc4random_bytes(16); print $RANDOM;
DESCRIPTION This set of functions maps the arc4random(3) family of libc functions into Perl code. All functions listed below are ithreads-safe. The internal XS functions are not, but you are not supposed to call them, either. On module load, perl's internal PRNG is re-seeded, as a bonus, using srand with an argument calculated from using arc4random_pushb on some entropy returned from rand's previous state. LOW-LEVEL FUNCTIONS arc4random() This function returns an unsigned 32-bit integer random value. arc4random_addrandom(pbuf) This function adds the entropy from pbuf into the libc pool and returns an unsigned 32-bit integer random value from it. arc4random_pushb(pbuf) This function first pushes the pbuf argument to the kernel if possible, then the entropy returned by the kernel into the libc pool, then returns an unsigned 32-bit integer random value from it. arc4random_pushk(pbuf) This function first pushes the pbuf argument to the kernel if possible, then returns an unsigned 32-bit integer random value from the kernel. This function is deprecated. Use arc4random_pushb instead. arc4random_stir() This procedure attempts to retrieve new entropy from the kernel and add it to the libc pool. Usually, this means you must have access to the urandom(4) device; create it inside chroot(2) jails first if you use them. have_kintf() This constant function returns 1 if arc4random_pushb and/or arc4random_pushk actually call the kernel interfaces, 0 if they merely map to arc4random_addrandom instead. HIGH-LEVEL FUNCTIONS arc4random_bytes(num[, pbuf]) This function returns a string containing as many random bytes as requested by the integral argument num. An optional pbuf argument is passed to the system first. arc4random_uniform(upper_bound) Calculate a uniformly distributed random number less than upper_bound avoiding "modulo bias". PACKAGE VARIABLES $RANDOM The $RANDOM returns a random value in the range [0; 32767] on each read attempt and pushes any value it is assigned to the kernel. It is tied at module load time. tie variable, 'BSD::arc4random'[, max] You can tie any scalar variable to this package; the max argument is the maximum number returned; if undefined, 0 or >= 0xFFFFFFFF, no bound is used, and values in the range [0; 2**32-1] are returned. They will behave like $RANDOM.
AUTHOR Thorsten Glaser <>
SEE ALSO The arc4random(3) manual page, available online at: <> Perl's rand and srand functions via perlfunc and perlfaq4. The plugin for Irssi, implementing the MirOS RANDEX protocol (entropy exchange over IRC), with CVSweb at: <> <> when it's done being written.
perl v5.22.1 2015-12-17 BSD::arc4random(3pm)
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BSD::arc4random(3pm) referred by
refer to arc4random(3) | chroot(2) | random(4)