mt_srand

(PHP 3>= 3.0.6, PHP 4 , PHP 5)

mt_srand -- Seed the better random number generator

Description

void mt_srand ( [int seed] )

Seeds the random number generator with seed. Since PHP 4.2.0, the seed becomes optional and defaults to a random value if omitted.

範例 1. mt_srand() example

<?php
// seed with microseconds
function make_seed()
{
    list(
$usec, $sec) = explode(' ', microtime());
    return (float)
$sec + ((float) $usec * 100000);
}
mt_srand(make_seed());
$randval = mt_rand();
?>

注: 由PHP 4.2.0 始,您不需要再使用 srand()mt_srand() 為亂數產生器提供種子,因為這已自動的提供了。

See also: mt_rand(), mt_getrandmax(), and srand().