X-Git-Url: https://git.saurik.com/apple/libc.git/blobdiff_plain/9385eb3d10ebe5eb398c52040ec3dbfba9b0cdcf..eb1cde05bb040f65c511ae4fa854abf1628afdf2:/stdlib/FreeBSD/random.3 diff --git a/stdlib/FreeBSD/random.3 b/stdlib/FreeBSD/random.3 index 172030d..9af134b 100644 --- a/stdlib/FreeBSD/random.3 +++ b/stdlib/FreeBSD/random.3 @@ -30,7 +30,7 @@ .\" SUCH DAMAGE. .\" .\" @(#)random.3 8.1 (Berkeley) 6/4/93 -.\" $FreeBSD: src/lib/libc/stdlib/random.3,v 1.17 2001/09/07 14:46:36 asmodai Exp $ +.\" $FreeBSD: src/lib/libc/stdlib/random.3,v 1.20 2004/07/02 23:52:12 ru Exp $ .\" .Dd June 4, 1993 .Dt RANDOM 3 @@ -81,9 +81,11 @@ 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 the bits generated by +generated by rand go through a cyclic pattern. +All the bits generated by .Fn random -are usable. For example, +are usable. +For example, .Sq Li random()&01 will produce a random binary value. @@ -100,7 +102,7 @@ as the seed. .Pp The .Fn srandomdev -routine initialize a state array using +routine initializes a state array using the .Xr random 4 random number device which returns good random numbers, suitable for cryptographic use. @@ -115,13 +117,15 @@ a fixed seed. 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 +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 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. @@ -174,6 +178,7 @@ is called with less than 8 bytes of state information, or if detects that the state information has been garbled, error messages are printed on the standard error output. .Sh SEE ALSO +.Xr arc4random 3 , .Xr rand 3 , .Xr srand 3 , .Xr random 4 @@ -189,3 +194,6 @@ 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 .