Seed the random number generator (original) (raw)

srand

(PHP 4, PHP 5, PHP 7)

srand — Seed the random number generator

Description

srand ([ int $seed ] ) : void

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

Note: There is no need to seed the random number generator with srand() ormt_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 integer seed value.

Return Values

No value is returned.

Examples

Example #1 srand() example

<?php // seed with microseconds function make_seed() { list($usec, $sec) = explode(' ', microtime()); return <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mi>s</mi><mi>e</mi><mi>c</mi><mo>+</mo></mrow><annotation encoding="application/x-tex">sec + </annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.6667em;vertical-align:-0.0833em;"></span><span class="mord mathnormal">sec</span><span class="mord">+</span></span></span></span>usec * 1000000; } srand(make_seed()); $randval = rand(); ?>

See Also