+++ /dev/null
-.\" Copyright (c) 1983, 1991, 1993
-.\" The Regents of the University of California. All rights reserved.
-.\"
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-.\" modification, are permitted provided that the following conditions
-.\" are met:
-.\" 1. Redistributions of source code must retain the above copyright
-.\" notice, this list of conditions and the following disclaimer.
-.\" 2. Redistributions in binary form must reproduce the above copyright
-.\" notice, this list of conditions and the following disclaimer in the
-.\" documentation and/or other materials provided with the distribution.
-.\" 4. Neither the name of the University nor the names of its contributors
-.\" may be used to endorse or promote products derived from this software
-.\" without specific prior written permission.
-.\"
-.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
-.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
-.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
-.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
-.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
-.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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-.\"
-.\" @(#)random.3 8.1 (Berkeley) 6/4/93
-.\" $FreeBSD: src/lib/libc/stdlib/random.3,v 1.22 2007/01/09 00:28:10 imp Exp $
-.\"
-.Dd June 4, 1993
-.Dt RANDOM 3
-.Os
-.Sh NAME
-.Nm initstate ,
-.Nm random ,
-.Nm setstate ,
-.Nm srandom ,
-.Nm srandomdev
-.Nd better random number generator; routines for changing generators
-.Sh LIBRARY
-.Lb libc
-.Sh SYNOPSIS
-.In stdlib.h
-.Ft char *
-.Fo initstate
-.Fa "unsigned seed"
-.Fa "char *state"
-.Fa "size_t size"
-.Fc
-.Ft long
-.Fo random
-.Fa void
-.Fc
-.Ft char *
-.Fo setstate
-.Fa "const char *state"
-.Fc
-.Ft void
-.Fo srandom
-.Fa "unsigned seed"
-.Fc
-.Ft void
-.Fo srandomdev
-.Fa void
-.Fc
-.Sh DESCRIPTION
-The
-.Fn random
-function
-uses a non-linear, additive feedback, random number generator, employing a
-default table of size 31 long integers.
-It returns successive pseudo-random
-numbers in the range from 0 to
-.if t 2\u\s731\s10\d\(mi1.
-.if n (2**31)\(mi1.
-The period of this random number generator is very large, approximately
-.if t 16\(mu(2\u\s731\s10\d\(mi1).
-.if n 16*((2**31)\(mi1).
-.Pp
-The
-.Fn random
-and
-.Fn srandom
-functions have (almost) the same calling sequence and initialization properties as the
-.Xr rand 3
-and
-.Xr srand 3
-functions.
-The difference is that
-.Xr rand 3
-produces a much less random sequence \(em in fact, the low dozen bits
-generated by rand go through a cyclic pattern.
-All of the bits generated by
-.Fn random
-are usable.
-For example,
-.Sq Li random()&01
-will produce a random binary
-value.
-.Pp
-Like
-.Xr srand 3 ,
-.Fn srandom
-sets the initial seed value for future calls to
-.Fn random .
-Like
-.Xr rand 3 ,
-.Fn random
-will by default produce a sequence of numbers that can be duplicated
-by calling
-.Fn srandom
-with the same seed.
-.Pp
-The
-.Fn srandomdev
-routine initializes a state array, using the
-.Xr random 4
-random number device which returns good random numbers,
-suitable for cryptographic use.
-Note that this particular seeding
-procedure can generate states which are impossible to reproduce by
-calling
-.Fn srandom
-with any value, since the succeeding terms in the
-state buffer are no longer derived from the LC algorithm applied to
-a fixed seed.
-.Pp
-The
-.Fn initstate
-routine allows a state array, passed in as an argument, to be initialized
-for future use.
-The size of the state array (in bytes) is used by
-.Fn initstate
-to decide how sophisticated a random number generator it should use \(em the
-more state, the better the random numbers will be.
-(Current "optimal" values for the amount of state information are
-8, 32, 64, 128, and 256 bytes; other amounts will be rounded down to
-the nearest known amount.
-Using less than 8 bytes will cause an error.)
-The seed for the initialization (which specifies a starting point for
-the random number sequence and provides for restarting at the same
-point) is also an argument.
-The
-.Fn initstate
-function
-returns a pointer to the previous state information array.
-.Pp
-Once a state has been initialized, the
-.Fn setstate
-routine provides for rapid switching between states.
-The
-.Fn setstate
-function
-returns a pointer to the previous state array; its
-argument state array is used for further random number generation
-until the next call to
-.Fn initstate
-or
-.Fn setstate .
-.Pp
-Once a state array has been initialized, it may be restarted at a
-different point either by calling
-.Fn initstate
-(with the desired seed, the state array, and its size) or by calling
-both
-.Fn setstate
-(with the state array) and
-.Fn srandom
-(with the desired seed).
-The advantage of calling both
-.Fn setstate
-and
-.Fn srandom
-is that the size of the state array does not have to be remembered after
-it is initialized.
-.Pp
-With 256 bytes of state information, the period of the random number
-generator is greater than
-.if t 2\u\s769\s10\d,
-.if n 2**69 ,
-which should be sufficient for most purposes.
-.Sh DIAGNOSTICS
-If
-.Fn initstate
-is called with less than 8 bytes of state information, or if
-.Fn setstate
-detects that the state information has been garbled, error
-messages are printed on the standard error output.
-.Sh LEGACY SYNOPSIS
-.Fd #include <stdlib.h>
-.Pp
-.Ft char *
-.br
-.Fo initstate
-.Fa "unsigned long seed"
-.Fa "char *state"
-.Fa "long size"
-.Fc ;
-.Pp
-.Ft char *
-.br
-.Fo setstate
-.Fa "char *state"
-.Fc ;
-.Pp
-.Ft void
-.br
-.Fo srandom
-.Fa "unsigned long seed"
-.Fc ;
-.Pp
-The type of each parameter is different in the legacy version.
-.Sh SEE ALSO
-.Xr arc4random 3 ,
-.Xr rand 3 ,
-.Xr srand 3 ,
-.Xr random 4 ,
-.Xr compat 5
-.Sh HISTORY
-These
-functions appeared in
-.Bx 4.2 .
-.Sh AUTHORS
-.An Earl T. Cohen
-.Sh BUGS
-About 2/3 the speed of
-.Xr rand 3 .
-.Pp
-The historical implementation used to have a very weak seeding; the
-random sequence did not vary much with the seed.
-The current implementation employs a better pseudo-random number
-generator for the initial state calculation.
-.Pp
-Applications requiring cryptographic quality randomness should use
-.Xr arc4random 3 .
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