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  1. Doc: improve documentation about random().

  1. What seed does random() use if setseed() is not called first?

    Carl Sopchak <carl@sopchak.me> — 2022-07-23T21:18:40Z

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    <p>There is one point about the documentation for random() and
      setseed() that is missing.  What is used to seed random() if
      setseed() isn't called first?  I assume it's something like
      /dev/random or /dev/urandom, but that's just a guess.  Can someone
      please enlighten me?</p>
    <p>Thanks for the help!</p>
    <p>Carl<br>
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  2. Re: What seed does random() use if setseed() is not called first?

    Tom Lane <tgl@sss.pgh.pa.us> — 2022-07-23T21:47:19Z

    Carl Sopchak <carl@sopchak.me> writes:
>     <p>There is one point about the documentation for random() and
>       setseed() that is missing.  What is used to seed random() if
>       setseed() isn't called first?  I assume it's something like
>       /dev/random or /dev/urandom, but that's just a guess.  Can someone
>       please enlighten me?</p>

We don't document this because it's platform- and version-dependent,
but yeah, generally /dev/urandom or local equivalent.

			regards, tom lane

  3. Re: What seed does random() use if setseed() is not called first?

    Carl Sopchak <carl@sopchak.me> — 2022-07-23T21:55:40Z

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    <p>Thank you for the quick reply!  But I wouldn't have bothered you
      if the documentation stated something to the effect of "While it's
      platform-dependent, if setseed() is not called, the random number
      generator is generally seeded by whatever method the operating
      system provides as a source of randomness, such as /dev/urandom on
      Linux/Unix, or &lt;???&gt; on Windows."</p>
    <p>Just a suggestion, hope this helps, and thanks again!</p>
    <p>Carl<br>
    </p>
    <div class="moz-cite-prefix">On 7/23/22 17:47, Tom Lane wrote:<br>
    </div>
    <blockquote type="cite" cite="mid:1220338.1658612839@sss.pgh.pa.us">
      <pre class="moz-quote-pre" wrap="">Carl Sopchak <a class="moz-txt-link-rfc2396E" href="mailto:carl@sopchak.me">&lt;carl@sopchak.me&gt;</a> writes:
</pre>
      <blockquote type="cite">
        <pre class="moz-quote-pre" wrap="">    &lt;p&gt;There is one point about the documentation for random() and
      setseed() that is missing.  What is used to seed random() if
      setseed() isn't called first?  I assume it's something like
      /dev/random or /dev/urandom, but that's just a guess.  Can someone
      please enlighten me?&lt;/p&gt;
</pre>
      </blockquote>
      <pre class="moz-quote-pre" wrap="">
We don't document this because it's platform- and version-dependent,
but yeah, generally /dev/urandom or local equivalent.

			regards, tom lane
</pre>
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  4. Re: What seed does random() use if setseed() is not called first?

    Tom Lane <tgl@sss.pgh.pa.us> — 2022-07-23T22:06:01Z

    Carl Sopchak <carl@sopchak.me> writes:
>     <p>Thank you for the quick reply!  But I wouldn't have bothered you
>       if the documentation stated something to the effect of "While it's
>       platform-dependent, if setseed() is not called, the random number
>       generator is generally seeded by whatever method the operating
>       system provides as a source of randomness, such as /dev/urandom on
>       Linux/Unix, or &lt;???&gt; on Windows."</p>

Hmm, I thought this already was documented, but it looks like not.
I'll see what I can do.

			regards, tom lane

  5. Re: What seed does random() use if setseed() is not called first?

    Carl Sopchak <carl@sopchak.me> — 2022-07-23T22:09:29Z

    
  If it is, somewhere, it's not on the Mathematical Functions page where random() and setseed() are documented.



  



  Thanks again...



  Carl



  



  On 7/23/22 18:06, Tom Lane wrote:



  Carl Sopchak <carl@sopchak.me> writes:

  
        <p>Thank you for the quick reply!  But I wouldn't have bothered you
      if the documentation stated something to the effect of "While it's
      platform-dependent, if setseed() is not called, the random number
      generator is generally seeded by whatever method the operating
      system provides as a source of randomness, such as /dev/urandom on
      Linux/Unix, or &lt;???&gt; on Windows."</p>

  
  
Hmm, I thought this already was documented, but it looks like not.
I'll see what I can do.

                        regards, tom lane