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>shm_open</A
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></A
><P
>    (unknown)</P
>shm_open&nbsp;--&nbsp;Create or open shared memory block</DIV
><DIV
CLASS="refsect1"
><A
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></A
><H2
>Description</H2
><DIV
CLASS="funcsynopsis"
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><P
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><P
><CODE
><CODE
CLASS="FUNCDEF"
>int <B
CLASS="function"
>shm_open</B
></CODE
> (int key, string flags, int mode, int size)</CODE
></P
><P
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><P
>&#13;     <B
CLASS="function"
>shm_open()</B
> can create or open a shared memory block.
    </P
><P
>&#13;     <B
CLASS="function"
>shm_open()</B
> takes 4 parameters: key, which is the
     system's id for the shared memory block, this parameter can be passed
     as a decimal or hex. The second parameter are the flags that you can use:
     <P
></P
><UL
><LI
><P
>&#13;        "a" for access (sets IPC_EXCL)
        use this flag when you need to open an existing shared memory segment
       </P
></LI
><LI
><P
>&#13;        "c" for create (sets IPC_CREATE)
        use this flag when you need to create a new shared memory segment.
       </P
></LI
></UL
>
     The third parameter is the mode, which are 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 ex. 0644.
     The last parameter is size of the shared memory block you wish to create
     in bytes.
     <DIV
CLASS="note"
><BLOCKQUOTE
CLASS="note"
><P
><B
>Note: </B
>
      Note: the 3rd and 4th should be entered as 0 if you are opening an
      existing memory segment. On success <B
CLASS="function"
>shm_open()</B
> will
      return an id that you can use to access the shared memory segment 
      you've created.
     </P
></BLOCKQUOTE
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>
    </P
><P
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><B
>Example 1. Create a new shared memory block</B
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><PRE
CLASS="programlisting"
>&#13;&#60;?php
$shm_id = shm_open(0x0fff, "c", 0644, 100);
?&#62;
      </PRE
></TD
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>
    </P
><P
>&#13;     This example opened a shared memory block with a system id of 0x0fff.
    </P
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