(PHP 3, PHP 4, PHP 5)
Seeds the random number generator with seed. Since PHP 4.2.0, the seed becomes optional and defaults to a random value if omitted.
Example 1. srand() example
<?php// seed with microsecondsfunction make_seed(){ list($usec, $sec) = explode(' ', microtime()); return (float) $sec + ((float) $usec * 100000);}srand(make_seed());$randval = rand();?>
Note: As of PHP 4.2.0, there is no need to seed the random number generator with srand() or mt_srand() as this is now done automatically.
See also: rand(), getrandmax(), and mt_srand().