Uniqid () function and microtime () function

The Uniqid () function generates a unique ID based on the current time in microseconds.
Grammar

Uniqid (prefix,more_entropy)

Parameter description
prefix is optional. Specify a prefix for the ID. This parameter is useful if two scripts generate IDs exactly in the same microsecond.
More_entropy is optional. Specify more entropy at the end of the return value

Description

If the prefix parameter is empty, the returned string has 13 string lengths. If the More_entropy parameter is set to True, it is 23 strings long.

If the More_entropy parameter is set to True, additional entropy is added at the end of the return value (using a combination line with the remainder generator), which results in better uniqueness.
return value

Returns a unique identifier in the form of a string.
Hints and Notes

Note: The ID generated by this function is not optimal due to system time. To generate an absolutely unique ID, use the MD5 () function (find in the string function Reference).

Definition and usage

The Microtime () function returns the current Unix timestamp and the number of microseconds.

Grammar

Microtime (Get_as_float)

Parameters	Description
Get_as_float	If the Get_as_float parameter is given and its value is equivalent to TRUE, the function returns a floating-point number.

echo Microtime (ture); echo "<br>";

Echo Uniqid (); echo "<br>";

echo MD5 (Uniqid (Microtime (ture), ture));

The output is:

1422072861.4654c31c1d7044c4138288389622ae5810434975f17fb7d

Uniqid () function and microtime () function