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>msg_receive</H1
><DIV
CLASS="refnamediv"
><A
NAME="AEN205521"
></A
><P
> (PHP 4 >= 4.3.0, PHP 5)</P
>msg_receive --
Receive a message from a message queue
</DIV
><DIV
CLASS="refsect1"
><A
NAME="AEN205524"
></A
><H2
>Description</H2
>bool <B
CLASS="methodname"
>msg_receive</B
> ( resource queue, int desiredmsgtype, int &msgtype, int maxsize, mixed &message [, bool unserialize [, int flags [, int &errorcode]]] )<BR
></BR
><P
> <B
CLASS="function"
>msg_receive()</B
> will receive the first message from the
specified <CODE
CLASS="parameter"
>queue</CODE
> of the type specified by
<CODE
CLASS="parameter"
>desiredmsgtype</CODE
>.
The type of the message that was received will be stored in
<CODE
CLASS="parameter"
>msgtype</CODE
>.
The maximum size of message to be accepted is specified by the
<CODE
CLASS="parameter"
>maxsize</CODE
>; if the message in the queue is larger
than this size the function will fail (unless you set
<CODE
CLASS="parameter"
>flags</CODE
> as described below).
The received message will be stored in <CODE
CLASS="parameter"
>message</CODE
>,
unless there were errors receiving the message, in which case the
optional <CODE
CLASS="parameter"
>errorcode</CODE
> will be set to the value of the
system errno variable to help you identify the cause.
</P
><P
> If <CODE
CLASS="parameter"
>desiredmsgtype</CODE
> is 0, the message from the front
of the queue is returned. If <CODE
CLASS="parameter"
>desiredmsgtype</CODE
> is
greater than 0, then the first message of that type is returned.
If <CODE
CLASS="parameter"
>desiredmsgtype</CODE
> is less than 0, the first
message on the queue with the lowest type less than or equal to the
absolute value of <CODE
CLASS="parameter"
>desiredmsgtype</CODE
> will be read.
If no messages match the criteria, your script will wait until a suitable
message arrives on the queue. You can prevent the script from blocking
by specifying <TT
CLASS="constant"
><B
>MSG_IPC_NOWAIT</B
></TT
> in the
<CODE
CLASS="parameter"
>flags</CODE
> parameter.
</P
><P
> <CODE
CLASS="parameter"
>unserialize</CODE
> defaults to <TT
CLASS="constant"
><B
>TRUE</B
></TT
>; if it is set to
<TT
CLASS="constant"
><B
>TRUE</B
></TT
>, the message is treated as though it was serialized using the same
mechanism as the session module. The message will be unserialized and
then returned to your script. This allows you to easily receive arrays
or complex object structures from other PHP scripts, or if you are using
the WDDX serializer, from any WDDX compatible source.
If <CODE
CLASS="parameter"
>unserialize</CODE
> is <TT
CLASS="constant"
><B
>FALSE</B
></TT
>, the message will be
returned as a binary-safe string.
</P
><P
> The optional <CODE
CLASS="parameter"
>flags</CODE
> allows you to pass flags to the
low-level msgrcv system call. It defaults to 0, but you may specify one
or more of the following values (by adding or ORing them together).
<DIV
CLASS="table"
><A
NAME="AEN205577"
></A
><P
><B
>表 1. Flag values for msg_receive</B
></P
><TABLE
BORDER="1"
CLASS="CALSTABLE"
><COL><COL><TBODY
><TR
><TD
><TT
CLASS="constant"
><B
>MSG_IPC_NOWAIT</B
></TT
></TD
><TD
>If there are no messages of the
<CODE
CLASS="parameter"
>desiredmsgtype</CODE
>, return immediately and do not
wait. The function will fail and return an integer value
corresponding to <TT
CLASS="constant"
><B
>MSG_ENOMSG</B
></TT
>.
</TD
></TR
><TR
><TD
><TT
CLASS="constant"
><B
>MSG_EXCEPT</B
></TT
></TD
><TD
>Using this flag in combination with a
<CODE
CLASS="parameter"
>desiredmsgtype</CODE
> greater than 0 will cause the
function to receive the first message that is not equal to
<CODE
CLASS="parameter"
>desiredmsgtype</CODE
>.</TD
></TR
><TR
><TD
><TT
CLASS="constant"
><B
>MSG_NOERROR</B
></TT
></TD
><TD
> If the message is longer than <CODE
CLASS="parameter"
>maxsize</CODE
>,
setting this flag will truncate the message to
<CODE
CLASS="parameter"
>maxsize</CODE
> and will not signal an error.
</TD
></TR
></TBODY
></TABLE
></DIV
>
</P
><P
> Upon successful completion the message queue data structure is updated as
follows: <TT
CLASS="literal"
>msg_lrpid</TT
> is set to the process-ID of the
calling process, <TT
CLASS="literal"
>msg_qnum</TT
> is decremented by 1 and
<TT
CLASS="literal"
>msg_rtime</TT
> is set to the current time.
</P
><P
> <B
CLASS="function"
>msg_receive()</B
> returns <TT
CLASS="constant"
><B
>TRUE</B
></TT
> on success or <TT
CLASS="constant"
><B
>FALSE</B
></TT
> on
failure. If the function fails, the optional
<CODE
CLASS="parameter"
>errorcode</CODE
> will be set to the value of the system
errno variable.
</P
><P
> See also <A
HREF="function.msg-remove-queue.html"
><B
CLASS="function"
>msg_remove_queue()</B
></A
>,
<A
HREF="function.msg-send.html"
><B
CLASS="function"
>msg_send()</B
></A
>,
<A
HREF="function.msg-stat-queue.html"
><B
CLASS="function"
>msg_stat_queue()</B
></A
> and
<A
HREF="function.msg-set-queue.html"
><B
CLASS="function"
>msg_set_queue()</B
></A
>.
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