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><H1
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>uniqid</H1
><DIV
CLASS="refnamediv"
><A
NAME="AEN126233"
></A
><P
> (PHP 3, PHP 4, PHP 5)</P
>uniqid -- Generate a unique ID</DIV
><DIV
CLASS="refsect1"
><A
NAME="AEN126236"
></A
><H2
>说明</H2
>string <B
CLASS="methodname"
>uniqid</B
> ( [string prefix [, bool more_entropy]] )<BR
></BR
><P
> Gets a prefixed unique identifier based on the current time in
microseconds.
</P
></DIV
><DIV
CLASS="refsect1"
><A
NAME="AEN126248"
></A
><H2
>参数</H2
><P
> <P
></P
><DIV
CLASS="variablelist"
><DL
><DT
><CODE
CLASS="parameter"
>prefix</CODE
></DT
><DD
><P
> Can be useful, for instance, if you generate identifiers
simultaneously on several hosts that might happen to generate the
identifier at the same microsecond.
</P
><P
> With an empty <CODE
CLASS="parameter"
>prefix</CODE
>, the returned string will
be 13 characters long. If <CODE
CLASS="parameter"
>more_entropy</CODE
> is
<TT
CLASS="constant"
><B
>TRUE</B
></TT
>, it will be 23 characters.
</P
></DD
><DT
><CODE
CLASS="parameter"
>more_entropy</CODE
></DT
><DD
><P
> If set to <TT
CLASS="constant"
><B
>TRUE</B
></TT
>, <B
CLASS="function"
>uniqid()</B
> will add additional
entropy (using the combined linear congruential generator) at the end
of the return value, which should make the results more unique.
</P
></DD
></DL
></DIV
>
</P
></DIV
><DIV
CLASS="refsect1"
><A
NAME="AEN126268"
></A
><H2
>返回值</H2
><P
> Returns the unique identifier, as a string.
</P
></DIV
><DIV
CLASS="refsect1"
><A
NAME="AEN126271"
></A
><H2
>范例</H2
><P
> If you need a unique identifier or token and you intend to give
out that token to the user via the network (i.e. session cookies),
it is recommended that you use something along these lines:
</P
><P
> This will create a 32 character identifier (a 128 bit hex number)
that is extremely difficult to predict.
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><A
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></A
><P
><B
>例 1. <B
CLASS="function"
>uniqid()</B
> Example</B
></P
><TABLE
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><TR
><TD
><code><font color="#000000">
<font color="#0000BB"><?php<br /></font><font color="#FF8000">// no prefix<br />// works only in PHP 5 and later versions<br /></font><font color="#0000BB">$token </font><font color="#007700">= </font><font color="#0000BB">md5</font><font color="#007700">(</font><font color="#0000BB">uniqid</font><font color="#007700">());<br /><br /></font><font color="#FF8000">// better, difficult to guess<br /></font><font color="#0000BB">$better_token </font><font color="#007700">= </font><font color="#0000BB">md5</font><font color="#007700">(</font><font color="#0000BB">uniqid</font><font color="#007700">(</font><font color="#0000BB">rand</font><font color="#007700">(), </font><font color="#0000BB">true</font><font color="#007700">));<br /></font><font color="#0000BB">?></font>
</font>
</code></TD
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>
</P
></DIV
><DIV
CLASS="refsect1"
><A
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></A
><H2
>更新日志</H2
><P
> <DIV
CLASS="informaltable"
><P
></P
><A
NAME="AEN126282"
></A
><TABLE
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><COL><COL><THEAD
><TR
><TH
>版本</TH
><TH
>说明</TH
></TR
></THEAD
><TBODY
><TR
><TD
>5.0.0</TD
><TD
> The <CODE
CLASS="parameter"
>prefix</CODE
> parameter was made optional.
</TD
></TR
><TR
><TD
>4.3.1</TD
><TD
> The limit of 114 characters long for <CODE
CLASS="parameter"
>prefix</CODE
>
was raised.
</TD
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>
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