Syntax
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.
The type of the message that was received will be stored in
msgtype.
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).
The received message will be stored in message,
unless there were errors receiving the message, in which case the
optional errorcode will be set to the value of the
system errno variable to help you identify the cause.
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.
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.
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).
Table 1. 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 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.
|
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.
msg_receive() returns TRUE on success or FALSE on
failure. If the function fails, the optional
errorcode will be set to the value of the system
errno variable.
See also msg_remove_queue(),
msg_send(),
msg_stat_queue() and
msg_set_queue().
