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uniqid
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uniqid

Name

uniqid — Generates a unique ID.

Synopsis

string uniqid(prefix); string prefix:

Returns

Unique value

Description

This handy function creates a unique identifier based on the current number of microseconds. An optional prefix of up to 114 characters can be used to differentiate between several types of IDs or to provide another level of abstraction. This prefix is prepended to the generated ID. Since this function is based on the microtime, the variety of the generated IDs is not optimal; when the system time is known, a small amount of predictability comes into place. To generate hard-to-reproduce IDs, see the md5() function.

Example

Example 354. Generate a unique ID

<?php
// See the random number generator
srand ((double) microtime () * 1000000);

// Generate a 12-character random string
$str = "";
for ($i = 0; $i < 12; ++$i) {
    $str .= chr(rand() % 26 + 97);
}

// ...and use it to make a unique ID more random
echo "Unique ID: ", uniqid($str);
?>

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PHP Functions Essential Reference. Copyright © 2002 by New Riders Publishing (Authors: Zak Greant, Graeme Merrall, Torben Wilson, Brett Michlitsch). This material may be distributed only subject to the terms and conditions set forth in the Open Publication License, v1.0 or later (the latest version is presently available at http://www.opencontent.org/openpub/). The authors of this book have elected not to choose any options under the OPL. This online book was obtained from http://www.fooassociates.com/phpfer/ and is designed to provide information about the PHP programming language, focusing on PHP version 4.0.4 for the most part. The information is provided on an as-is basis, and no warranty or fitness is implied. All persons and entities shall have neither liability nor responsibility to any person or entity with respect to any loss or damage arising from the information contained in this book.