Hi Jonny, On 12/27/22 22:37, Jonny Grant wrote:
Hi Alex On 26/12/2022 22:29, Alejandro Colomar wrote:Hi Jonny, On 12/26/22 22:50, Jonny Grant wrote:Hi AlejandroPlease send also to my email.Please find below a patch. 2022-12-26 Jonathan Grant <jg@xxxxxxxx> * man3/rand.3: Add example to rand.3 seed with time(NULL) From 2d4501354ea6c465173fe6c089dfbcc80393a644 Mon Sep 17 00:00:00 2001 From: Jonathan Grant <jg@xxxxxxxx> Date: Mon, 26 Dec 2022 21:48:17 +0000 Subject: [PATCH] add rand.3 example Signed-off-by: Jonathan Grant <jg@xxxxxxxx>time(NULL) is not too good. If you call it several times per second, you'll find that it only changes the seed every second. There are better ways to produce a good seed. However, I prefer suggesting arc4random() rather than workarounding rand(3) to get good results. Florian, did you already merge arc4random() to glibc?Hopefully arc4random will come soon. Maybe rand.3 could then be updated to SEE ALSO that. > I would only mention to call srand once to seed, but you're right there are lots of other ways to get a seed. Jonny
But consider the following case:You're testing some program with random data in a loop. And the program executes in less than a second. Then srand(3) will be called several times per second with the same seed, and you'll get useless results. I faced that exact situation a few years ago :)
Cheers, Alex -- <http://www.alejandro-colomar.es/>
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