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srand

(PHP 4, PHP 5)

srandSeed the random number generator

Description

void srand ([ int $seed ] )

Seeds the random number generator with seed or with a random value if no seed is given.

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.

Parameters

seed

Optional seed value

Return Values

No value is returned.

Changelog

Version Description
4.2.0 The seed becomes optional and defaults to a random value if omitted.

Examples

Example #1 srand() example

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

See Also

PHP Manual