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msg_send

(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)

msg_sendEviar un mensaje a una cola de mensajes

Descripción

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

msg_send() envía un message del tipo msgtype (DEBE ser mayor que 0) a la cola de mensajes especificada por queue.

Parámetros

queue

msgtype

message

serialize

El parámetro opcional serialize controla el modo de enviar el mensaje dado por message. serialize es por defecto true lo que significa que message es serializado usando el mismo mecanismo que el módulo de sesión antes de ser enviado a la cola. Esto permite matrices y objetos complejos para ser enviados a otros scripts de PHP, o si se está usando el serializador WDDX, para cualquier cliente compatible con WDDX.

blocking

Si el mensaje es demasiado largo para caber en la cola el script esperará hasta que otro proceso lea los mensajes de la cola y libere sufieciente espacio para el mensaje que se va a enviar. Esto se llama bloqueo; se puede prevenir el bloqueo estableciendo el parámetro blocking a false, en cuyo caso msg_send() devolverá inmediatamente false si el mensaje es demasiado grande para la cola, y establecerá el parámetro opcional errorcode a MSG_EAGAIN, indicando que se debería intentar enviar el mensaje de nuevo un poco más tarde.

errorcode

Valores devueltos

Devuelve true en caso de éxito o false en caso de error.

Al finalizar con éxito, la estructura de datos de la cola de mensajes se actualiza como sigue: msg_lspid se establece al ID del proceso de llamada, msg_qnum se incrementa en 1 y msg_stime se establece al momento actual.

Ver también

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User Contributed Notes 6 notes

up
5
Muffinman
11 years ago
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.
up
5
qeekin at gmail dot com
9 years ago
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:
/**
* Example how to use System V Messages Queues with PHP and C program.
* This is simple server which create message queue and receive message from it.
* Based on Beej's Guide to Unix IPC
* Autor: Jan Drazil, <qeekin at gmail dot com>
*/

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

/* Buffer struct for receiving messages */
struct php_buf {
long mtype;
char msg[200];
};

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

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

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

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

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

/* Eliminate segmentation fault */
buf.msg[199] = '\0';

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

/* Destroy message queue */
if(msgctl(msqid, IPC_RMID, NULL) == -1) {
perror("msgctl");
exit(EXIT_FAILURE);
}

return EXIT_SUCCESS;
}

test_queue.php:
<?php
/**
* Example how to use System V Messages Queues with PHP and C program.
* This is simple server which create message queue and receive message from it.
* Based on Beej's Guide to Unix IPC
* Autor: Jan Drazil, <qeekin at gmail dot com>
*/

/* Generate key, param fot ftok must be same as in test_msg.c */
if(($key = ftok("/var/www/index.php", "G")) == -1)
die(
"ftok");

if(!
msg_queue_exists($key))
die(
"message queue doesn't exists");

/* Connect to message queue */
if(($msqid = msg_get_queue($key)) === FALSE)
die(
"msg_get_queue");

echo
"Sending text to msg queue.\n";

/* Send message to C program */
if(!msg_send($msqid, 12, "Hello from PHP!\0", false))
die(
"msg_send");

echo
"Done"
?>
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1
michael dot NO dot SP dot AM dot cordover+php at gmail dot com
14 years ago
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).
up
0
shepik at yandex dot ru
14 years ago
$msgtype used in msg_send function can be any positive integer.
up
-1
webmaster at toolshed51 dot com
20 years ago
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";
?>
up
-1
bryan-boone at msn dot com
15 years ago
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.
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