uniqid
(PHP 4, PHP 5)
uniqid — Generate a unique ID
说明
string uniqid ([ string $prefix = "" [, bool $more_entropy = false ]] )Gets a prefixed unique identifier based on the current time in microseconds.
参数
- prefix
-
Can be useful, for instance, if you generate identifiers simultaneously on several hosts that might happen to generate the identifier at the same microsecond.
With an empty prefix, the returned string will be 13 characters long. If more_entropy is TRUE, it will be 23 characters.
- more_entropy
-
If set to TRUE, uniqid() will add additional entropy (using the combined linear congruential generator) at the end of the return value, which should make the results more unique.
返回值
Returns the unique identifier, as a string.
范例
Example #1 uniqid() Example
<?php
printf("uniqid(): %s
", uniqid());
printf("uniqid('php_'): %s
", uniqid('php_'));
printf("uniqid('', true): %s
", uniqid('', true));
?>
更新日志
| 版本 | 说明 |
|---|---|
| 5.0.0 | The prefix parameter was made optional. |
| 4.3.1 | The limit of 114 characters long for prefix was raised. |
注释
Note:
Under Cygwin, the more_entropy must be set to TRUE for this function to work.
