srandomdev() vs srandom() vs arc4random()

[Kris Kennaway]

On Tue, May 24, 2005 at 09:13:45PM -0400, Nicolas Blais wrote:
> I'm developping a software that uses random generated numbers. Since these 
> numbers must be as "chaotic" as possible, I'm using srandomdev(). My problem 
> is that I'm only able to compile my software on *BSD and certain distros of 
> Linux seem to be stripped of the call. This forces me to rely on 
> srandom(time(NULL)) for portability.
> 
> I would like to know how "random" (that is, how inprobable a pattern will 
> appear) if I use srandom(time(NULL)) instead of srandomdev().
>
> Also, would arc4random() be any better in getting the least pattern creation.

arc4random() should produce higher quality randomness, although
srandom() may be good enough for your needs.

> Finally, is there is a way to check if the call srandomdev() exists on other 
> OSes?

Sure, compile a test app in your configure script :-)

Kris
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