At 23:33 12.03.2003, Justin French said:
--------------------[snip]--------------------
>Put this code in your shared library of functions (adapted from manual,
>untested):
><?
>function randNumber($min=1000,$max=99999)
> {
> // build a seed
> list($usec, $sec) = explode(' ', microtime());
> $seed = (float) $sec + ((float) $usec * 100000);
>
> // seed random generator
> srand($seed);
>
> // return random number
> return rand($min,$max);
> }
>?>
--------------------[snip]--------------------
May I?
It's usually not a good idea to re-seed the randum number generator during
a single script instance, as this might use the same seed more than once,
resulting in the identical random sequence...
To avoid reseeding, you could e.g. use a static variable in your
randNumber() function:
function randNumber($min=1000,$max=99999)
{
static $is_seeded = false;
if (!$is_seeded) {
$is_seeded = true;
// build a seed
list($usec, $sec) = explode(' ', microtime());
$seed = (float) $sec + ((float) $usec * 100000);
// seed random generator
srand($seed);
}
...
I prefer to add a string generated by uniqid(), such as
<img src="myimg.jpg?r=<?php echo uniqid('',true);?>">
uniqid() uses the entropy generated by the opsys random device (if
available) in an attempt to make this truly random.
--
>O Ernest E. Vogelsinger
(\) ICQ #13394035
^ http://www.vogelsinger.at/
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