From owner-freebsd-hackers  Wed Feb 19  0:22:55 2003
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To: Paul Herman <pherman@frenchfries.net>
Cc: Peter Jeremy <peterjeremy@optushome.com.au>,
	FreeBSD Hackers <hackers@FreeBSD.ORG>
Subject: Re: arc4random() range 
From: phk@phk.freebsd.dk
In-Reply-To: Your message of "Wed, 19 Feb 2003 00:16:57 PST."
             <20030218232210.T240-100000@mammoth.eat.frenchfries.net> 
Date: Wed, 19 Feb 2003 09:22:49 +0100
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In message <20030218232210.T240-100000@mammoth.eat.frenchfries.net>, Paul Herma
n writes:

>  arc4random() returns random numbers in the range of 0 to
>  (2**32)-1, and therefore has twice the range of RAND_MAX.

Good.

>  EXAMPLES
>  The following produces a drop-in replacement for the traditional
>  random() and rand() functions using arc4random():
>      #define arc4random31()   (arc4random() & 0x7FFFFFFF)

Not good.  Only true on 32 bit archs.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

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