srand

(PHP 4, PHP 5, PHP 7, PHP 8)

srandSeed the random number generator

Description

srand(int $seed = 0, int $mode = MT_RAND_MT19937): void

Seeds the random number generator with seed or with a random value if seed is 0.

Note: There is no need to seed the random number generator with srand() or mt_srand() as this is done automatically.

Note: As of PHP 7.1.0, srand() has been made an alias of mt_srand().

Parameters

seed

An arbitrary int seed value.

Return Values

No value is returned.

Changelog

Version Description
7.1.0 srand() has been made an alias of mt_srand().

Examples

Example #1 srand() example

<?php
// seed with microseconds
function make_seed()
{
  list(
$usec$sec) = explode(' 'microtime());
  return 
$sec $usec 1000000;
}
srand(make_seed());
$randval rand();
?>

See Also

  • rand() - Generate a random integer
  • getrandmax() - Show largest possible random value
  • mt_srand() - Seeds the Mersenne Twister Random Number Generator