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PHP uniqid () function

PHP Misc Reference Manual PHP Misc Reference Manual

Examples

Generates a unique ID:

<?php
echo uniqid();
?>

Running instance »

Definition and Usage

uniqid () function is based on the current time in microseconds, generating a unique ID.

Note: Due tothe time-based system, generated by the function ID is not optimal. To generate absolute unique ID, please use the md5 () function.


grammar

uniqid( prefix,more_entropy )

参数 描述
prefix 可选。规定唯一 ID 的前缀。如果两个脚本恰好在相同的微秒生成 ID,该参数很有用。
more_entropy 可选。规定位于返回值末尾的更多的熵。这将让结果更具唯一性。当设置为 TRUE,返回字符串为 23 个字符。默认是 FALSE,返回字符串为 13 个字符。

technical details

return value: Unique identifier is returned as a string.
PHP version: 4+
Update log: In PHP 5.0 in, prefix parameter became optional.

In the PHP 4.3.1, prefix 114-character length limit increased.


PHP Misc Reference Manual PHP Misc Reference Manual