uniqid – PHP Function

Syntax :

Description :

The uniqid() function generates a unique ID based on the microtime (current time in microseconds). This is an inbuilt function of PHP.

ID created generated from the function is not unique because it is based on the system time and is not cryptographically secured. Thus it should not be for cryptographical purposes.

The uniqid( ) function accepts prefix and more_entropy as parameters and returns timestamp based unique identifier as a string.

Parameter :

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Name, Required /Optional, Value Type, Description

prefix, Optional, String , It specifies a prefix(user generated) to the unique ID and its useful when two scripts generate ids at exactly the same microsecond.
more_entropy, Optional,  Boolean, Specifies more entropy at the end of the return value. This will make the result more unique. When set to TRUE then return string will be 23 characters. Default is FALSE and the return string will be 13 characters long.

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Output :

It returns the unique value as a string.

ChangeLog :

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Version, Description
PHP 5.0 , The prefix parameter became optional.
PHP 4.3.1,The limit of 114 characters long for prefix was raised in this version.
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uniqid() – PHP Functions Example 1 :

<?php 
// This will generate unique id like this 5bbf0518c4013
echo uniqid();  
?>

Output of the program will be different each time when you run the code based on time of your system. Below will be the output when you run the function

uniqid() – PHP Functions Example 2 : Use of Prefix

<?php 
// This will generate unique id with prefix tutorialmines
$strExample = uniqid(tutorialmines); 
  
echo $strExample; 
?>

The following code in written in the file “test-frontf.txt” :

<?php 
// This will generate unique id with prefix tutorialmines
$strExample = uniqid(tutorialmines,TRUE); 
  
echo $strExample; 
?>