mirror of
https://github.com/lcn2/calc.git
synced 2025-08-19 01:13:27 +03:00
79 lines
2.5 KiB
Plaintext
79 lines
2.5 KiB
Plaintext
NAME
|
|
seed - return a value that may be used to seed a pseudo-random generator
|
|
|
|
SYNOPSIS
|
|
seed()
|
|
|
|
TYPES
|
|
return integer
|
|
|
|
DESCRIPTION
|
|
Generate a pseudo-random seed based on a collection of system and process
|
|
information. The seed() builtin function returns a value:
|
|
|
|
0 <= seed < 2^64
|
|
|
|
IMPORTANT WARNING:
|
|
|
|
It should be pointed out that the information collected by seed
|
|
is almost certainly non-chaotic. This function is likely not
|
|
suitable for applications (such as cryptographic applications)
|
|
where the unpredictability of seeds is critical. For such critical
|
|
applications, LavaRnd should be used. See the URL:
|
|
|
|
http://www.LavaRnd.org/
|
|
|
|
for information about seeding a pseudo-random number generator
|
|
(such as rand() or random()) with the cryptographic hash of the
|
|
digitization of chaotic system.
|
|
|
|
Given the above warning, this builtin function produces a seed that is
|
|
suitable for most applications that desire a different pseudo-random
|
|
sequence each time they are run.
|
|
|
|
The return value of this builtin function should NOT be considered
|
|
a random or pseudo-random value. The return value should be used
|
|
as an argument to a seed function such as srand() or srandom().
|
|
|
|
EXAMPLE
|
|
> print srand(seed())
|
|
RAND state
|
|
|
|
> print srandom(seed())
|
|
RAND state
|
|
|
|
LIMITS
|
|
none
|
|
|
|
LINK LIBRARY
|
|
NUMBER *pseudo_seed(void)
|
|
|
|
SEE ALSO
|
|
seed, srand, randbit, isrand, rand, random, srandom, israndom
|
|
|
|
## Copyright (C) 1999 Landon Curt Noll
|
|
##
|
|
## Calc is open software; you can redistribute it and/or modify it under
|
|
## the terms of the version 2.1 of the GNU Lesser General Public License
|
|
## as published by the Free Software Foundation.
|
|
##
|
|
## Calc is distributed in the hope that it will be useful, but WITHOUT
|
|
## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
|
|
## or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
|
|
## Public License for more details.
|
|
##
|
|
## A copy of version 2.1 of the GNU Lesser General Public License is
|
|
## distributed with calc under the filename COPYING-LGPL. You should have
|
|
## received a copy with calc; if not, write to Free Software Foundation, Inc.
|
|
## 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
|
|
##
|
|
## @(#) $Revision: 29.3 $
|
|
## @(#) $Id: seed,v 29.3 2001/05/13 13:26:26 chongo Exp $
|
|
## @(#) $Source: /usr/local/src/cmd/calc/help/RCS/seed,v $
|
|
##
|
|
## Under source code control: 1999/10/03 10:04:29
|
|
## File existed as early as: 1999
|
|
##
|
|
## chongo <was here> /\oo/\ http://www.isthe.com/chongo/
|
|
## Share and enjoy! :-) http://www.isthe.com/chongo/tech/comp/calc/
|