shmop_open
You should always serialize data written in shared memory.
And when you are reading data you should always unserialize.
<?php
$data = 'test';
$shm_bytes_written = shmop_write($shm_id, serialize($data), 0);
$shm_data = unserialize(shmop_read($shm_id, 0, $shm_bytes_written));
?>
shmop_read
(PHP 4 >= 4.0.4, PHP 5)
shmop_read — Lit des données à partir d'un bloc
Description
string shmop_read
( int
$shmid
, int $start
, int $count
)shmop_read() lit une chaîne dans une bloc de mémoire partagée.
Liste de paramètres
-
shmid -
L'identifiant du bloc mémoire partagé, créé par la fonction shmop_open()
-
start -
Position depuis laquelle on doit commencer à lire
-
count -
Le nombre d'octets à lire
Valeurs de retour
Retourne les données ou FALSE si une erreur survient.
Exemples
Exemple #1 Lit un bloc de mémoire partagée
<?php
$shm_data = shmop_read($shm_id, 0, 50);
?>
Cet exemple lit 50 octets dans le bloc de mémoire partagée et les place dans $shm_data.
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User Contributed Notes
shmop_read - [4 notes]
Milan Cvejic ¶
4 years ago
Craig Manley ¶
8 years ago
shmop_read() reads and returns the whole memory segment's data. This is not useful if you're just working with strings. If you need to read a string from shared memory, call str_from_mem() on the result of shmop_read(). Similarly when writing strings to memory (instead of binary data), null terminate your strings with str_to_nts() before passing the value on to shmop_write().
function str_to_nts($value) {
return "$value\0";
}
function str_from_mem(&$value) {
$i = strpos($value, "\0");
if ($i === false) {
return $value;
}
$result = substr($value, 0, $i);
return $result;
}
slavapl at mailandnews dot com ¶
12 years ago
Also you can use the shmop_size() function to determine the block size.
macmaster at pobox dot com ¶
12 years ago
When i need to read the whole string at that shm pointer, setting the count parameter to zero (0) seems work for me.