note 8986 modified in function.srand by felipe

It is REALLY essential to make sure that srand is called only once. This is a bit difficult if the call is hidden somewhere in third-party code you include. For example, I used a standard banner script that *seemed* to work well putting three random banners in one frame. But in the long run, the choice appeared somewhat biased - probably because srand was called once per banner, not once per run. It would be nice if the random number generator worked like in PERL: If You use the random function without having called srand ever before in a script, srand is invoked before (and automatically with a nice seed, hopefully). I suggest that one should do something like this: <?php if (!$GLOBALS["IHaveCalledSrandBefore"]++) { srand((double) microtime() * 1000000); } ?> (Depending on the situation, one might also work with a static variable instead) --was-- It is REALLY essential to make sure that srand is called only once. This is a bit difficult if the call is hidden somewhere in third-party code you include. For example, I used a standard banner script that *seemed* to work well putting three random banners in one frame. But in the long run, the choice appeared somewhat biased - probably because srand was called once per banner, not once per run. It would be nice if the random number generator worked like in PERL: If You use the random function without having called srand ever before in a script, srand is invoked before (and automatically with a nice seed, hopefully). I suggest that one should do something like this: <pre> if (!$GLOBALS["IHaveCalledSrandBefore"]++) { srand((double) microtime() * 1000000); } </pre> (Depending on the situation, one might also work with a static variable instead) http://php.net/manual/en/function.srand.php