msg_receive
(PHP 4 >= 4.3.0, PHP 5)
msg_receive — Receive a message from a message queue
说明
bool msg_receive
( resource $queue
, int $desiredmsgtype
, int &$msgtype
, int $maxsize
, mixed &$message
[, bool $unserialize
[, int $flags
[, int &$errorcode
]]] )
msg_receive() will receive the first message from the
specified queue
of the type specified by
desiredmsgtype
.
参数
-
queue
-
-
desiredmsgtype
-
If desiredmsgtype
is 0, the message from the front
of the queue is returned. If desiredmsgtype
is
greater than 0, then the first message of that type is returned.
If desiredmsgtype
is less than 0, the first
message on the queue with the lowest type less than or equal to the
absolute value of desiredmsgtype
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 MSG_IPC_NOWAIT in the
flags
parameter.
-
msgtype
-
The type of the message that was received will be stored in this
parameter.
-
maxsize
-
The maximum size of message to be accepted is specified by the
maxsize
; if the message in the queue is larger
than this size the function will fail (unless you set
flags
as described below).
-
message
-
The received message will be stored in message
,
unless there were errors receiving the message.
-
unserialize
-
unserialize
defaults to TRUE; if it is set to
TRUE, 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 unserialize
is FALSE, the message will be
returned as a binary-safe string.
-
flags
-
The optional flags
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).
Flag values for msg_receive
| MSG_IPC_NOWAIT |
If there are no messages of the
desiredmsgtype
, return immediately and do not
wait. The function will fail and return an integer value
corresponding to MSG_ENOMSG.
|
| MSG_EXCEPT |
Using this flag in combination with a
desiredmsgtype
greater than 0 will cause the
function to receive the first message that is not equal to
desiredmsgtype
. |
| MSG_NOERROR |
If the message is longer than maxsize
,
setting this flag will truncate the message to
maxsize
and will not signal an error.
|
-
errorcode
-
If the function fails, the optional errorcode
will be set to the value of the system errno variable.
返回值
如果成功则返回 TRUE，失败则返回 FALSE。
Upon successful completion the message queue data structure is updated as
follows: msg_lrpid is set to the process-ID of the
calling process, msg_qnum is decremented by 1 and
msg_rtime is set to the current time.