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>shmop_open</H1
><DIV
CLASS="refnamediv"
><A
NAME="AEN208996"
></A
><P
> (PHP 4 >= 4.0.4, PHP 5)</P
>shmop_open -- Create or open shared memory block</DIV
><DIV
CLASS="refsect1"
><A
NAME="AEN208999"
></A
><H2
>说明</H2
>int <B
CLASS="methodname"
>shmop_open</B
> ( int key, string flags, int mode, int size )<BR
></BR
><P
> <B
CLASS="function"
>shmop_open()</B
> can create or open a shared memory block.
</P
></DIV
><DIV
CLASS="refsect1"
><A
NAME="AEN209018"
></A
><H2
>参数</H2
><P
> <P
></P
><DIV
CLASS="variablelist"
><DL
><DT
><CODE
CLASS="parameter"
>key</CODE
></DT
><DD
><P
> System's id for the shared memory block.
Can be passed as a decimal or hex.
</P
></DD
><DT
><CODE
CLASS="parameter"
>flags</CODE
></DT
><DD
><P
> The flags that you can use:
<P
></P
><UL
><LI
><P
> "a" for access (sets SHM_RDONLY for shmat)
use this flag when you need to open an existing shared memory
segment for read only
</P
></LI
><LI
><P
> "c" for create (sets IPC_CREATE)
use this flag when you need to create a new shared memory segment
or if a segment with the same key exists, try to open it for read
and write
</P
></LI
><LI
><P
> "w" for read & write access
use this flag when you need to read and write to a shared memory
segment, use this flag in most cases.
</P
></LI
><LI
><P
> "n" create a new memory segment (sets IPC_CREATE|IPC_EXCL)
use this flag when you want to create a new shared memory segment
but if one already exists with the same flag, fail. This is useful
for security purposes, using this you can prevent race condition
exploits.
</P
></LI
></UL
>
</P
></DD
><DT
><CODE
CLASS="parameter"
>mode</CODE
></DT
><DD
><P
> The permissions that you wish to assign to your memory segment, those
are the same as permission for a file. Permissions need to be passed
in octal form, like for example <TT
CLASS="literal"
>0644</TT
>
</P
></DD
><DT
><CODE
CLASS="parameter"
>size</CODE
></DT
><DD
><P
> The size of the shared memory block you wish to create in bytes
</P
></DD
></DL
></DIV
>
<DIV
CLASS="note"
><BLOCKQUOTE
CLASS="note"
><P
><B
>注意: </B
>
Note: the 3rd and 4th should be entered as 0 if you are opening an
existing memory segment.
</P
></BLOCKQUOTE
></DIV
>
</P
></DIV
><DIV
CLASS="refsect1"
><A
NAME="AEN209054"
></A
><H2
>返回值</H2
><P
> On success <B
CLASS="function"
>shmop_open()</B
> will return an id that you can
use to access the shared memory segment you've created. <TT
CLASS="constant"
><B
>FALSE</B
></TT
> is
returned on failure.
</P
></DIV
><DIV
CLASS="refsect1"
><A
NAME="AEN209059"
></A
><H2
>范例</H2
><P
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><A
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></A
><P
><B
>例 1. Create a new shared memory block</B
></P
><TABLE
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><TR
><TD
><code><font color="#000000">
<font color="#0000BB"><?php<br />$shm_key </font><font color="#007700">= </font><font color="#0000BB">ftok</font><font color="#007700">(</font><font color="#0000BB">__FILE__</font><font color="#007700">, </font><font color="#DD0000">'t'</font><font color="#007700">);<br /></font><font color="#0000BB">$shm_id </font><font color="#007700">= </font><font color="#0000BB">shmop_open</font><font color="#007700">(</font><font color="#0000BB">$shm_key</font><font color="#007700">, </font><font color="#DD0000">"c"</font><font color="#007700">, </font><font color="#0000BB">0644</font><font color="#007700">, </font><font color="#0000BB">100</font><font color="#007700">);<br /></font><font color="#0000BB">?></font>
</font>
</code></TD
></TR
></TABLE
></DIV
></TD
></TR
></TABLE
>
</P
><P
> This example opened a shared memory block with a system id returned by
<A
HREF="function.ftok.html"
><B
CLASS="function"
>ftok()</B
></A
>.
</P
></DIV
><DIV
CLASS="refsect1"
><A
NAME="AEN209067"
></A
><H2
>参见</H2
><P
> <P
></P
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><A
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><B
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></A
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><B
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>shmop_delete()</B
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