msg_send

(PHP 4 >= 4.3.0, PHP 5)

msg_send — Send a message to a message queue

说明

bool msg_send ( resource $queue , int $msgtype , mixed $message [, bool $serialize = true [, bool $blocking = true [, int &$errorcode ]]] )

msg_send() sends a message of type msgtype (which MUST be greater than 0) to the message queue specified by queue.

参数

queue
msgtype
message
serialize: The optional serialize controls how the message is sent. serialize defaults to TRUE which means that the message is serialized using the same mechanism as the session module before being sent to the queue. This allows complex arrays and objects to be sent to other PHP scripts, or if you are using the WDDX serializer, to any WDDX compatible client.
blocking: If the message is too large to fit in the queue, your script will wait until another process reads messages from the queue and frees enough space for your message to be sent. This is called blocking; you can prevent blocking by setting the optional blocking parameter to FALSE , in which case msg_send() will immediately return FALSE if the message is too big for the queue, and set the optional errorcode to MSG_EAGAIN , indicating that you should try to send your message again a little later on.
errorcode

返回值

成功时返回 TRUE ，或者在失败时返回 FALSE 。

Upon successful completion the message queue data structure is updated as follows: msg_lspid is set to the process-ID of the calling process, msg_qnum is incremented by 1 and msg_stime is set to the current time.

参见

msg_remove_queue() - Destroy a message queue
msg_receive() - Receive a message from a message queue
msg_stat_queue() - Returns information from the message queue data structure
msg_set_queue() - Set information in the message queue data structure

用户评论:

[#1] qeekin at gmail dot com [2014-04-11 08:51:53]

I created example how to comunnicate with programe written in C throught messages queues. First run C program (it will create queue) then PHP script.

C code compile with: gcc -std=c99 -o test_queue test_queue.c

test_queue.c:

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/msg.h>

struct php_buf {
long mtype;
char msg[200];
};

int main(void)
{
struct php_buf buf;
int msqid;
key_t key;


if((key = ftok("/var/www/index.php", 'G')) == -1) {
perror("ftok");
exit(EXIT_FAILURE);
}


if((msqid = msgget(key, 0666 | IPC_CREAT)) == -1) {
perror("msgget");
exit(EXIT_FAILURE);
}

printf("Ready to get string from PHP!\n");


if(msgrcv(msqid, &buf, sizeof(buf.msg)-1, 0, 0) == -1) {
perror("msgrcv");
exit(EXIT_FAILURE);
}


buf.msg[199] = '\0';

printf("Recieved from PHP: %s\n", buf.msg);


if(msgctl(msqid, IPC_RMID, NULL) == -1) {
perror("msgctl");
exit(EXIT_FAILURE);
}

return EXIT_SUCCESS;
}

test_queue.php:
<?php if(($key = ftok("/var/www/index.php", "G")) == -1)     die("ftok"); if(!msg_queue_exists($key))     die("message queue doesn't exists"); if(($msqid = msg_get_queue($key)) === FALSE)     die("msg_get_queue"); echo "Sending text to msg queue.\n"; if(!msg_send($msqid, 12, "Hello from PHP!\0", false))     die("msg_send"); echo "Done" ?>

[#2] Muffinman [2012-11-15 10:24:33]

When sending non-complex (serialize = false) messages to a program in C, you need to add the null character to the string (\0). Otherwise the previous message will be partially visible if it is longer than the current message. Took some kind help from comp.lang.php for me to figure that out. While it seems so obvious now, I thought I'd share it here.

[#3] michael dot NO dot SP dot AM dot cordover+php at gmail dot com [2009-10-16 04:10:46]

After about an hour of debugging I've discovered the meaning of the undocumented "PHP Warning: msg_send(): msgsnd failed: Invalid argument" ($errorcode = 13).

This occurred when the size of $message was larger than msg_qbytes (see msg_stat_queue() for how to determine and change msg_qbytes).

[#4] shepik at yandex dot ru [2009-07-02 07:04:34]

$msgtype used in msg_send function can be any positive integer.

[#5] bryan-boone at msn dot com [2008-05-14 15:39:55]

I think it is kinda lame why I cannot find out (easily) explicitly which types of messages are allowed and which ones are not. Maybe we can start our own little list. I know that strings work, and arrays do not.

[#6] webmaster at toolshed51 dot com [2003-04-10 03:51:16]

Sample sending webpage, see msg_receive for matching service

<?php $MSGKEY = 519051; $msg_id = msg_get_queue ($MSGKEY, 0600); if (!msg_send ($msg_id, 1, 'Hi', true, true, $msg_err)) echo "Msg not sent because $msg_err\n"; ?>