Creates or open a shared memory segment - Справочник: PHP5.4

Описание

resource shm_attach ( int $key [, int $memsize [, int $perm = 0666 ]] )

shm_attach() returns an id that can be used to access the System V shared memory with the given key, the first call creates the shared memory segment with memsize and the optional perm-bits perm.

A second call to shm_attach() for the same key will return a different shared memory identifier, but both identifiers access the same underlying shared memory. memsize and perm will be ignored.

Список параметров

key: A numeric shared memory segment ID
memsize: The memory size. If not provided, default to the sysvshm.init_mem in the php.ini, otherwise 10000 bytes.
perm: The optional permission bits. Default to 0666.

Возвращаемые значения

Returns a shared memory segment identifier.

Список изменений

Версия	Описание
5.3.0	This function now returns a resource instead of an integer.

Примечания

Замечание:
This function used to return an integer value prior to PHP 5.3.0. To achieve the same value in a portable manner, the return value can be cast to an integer like:

<?php // Create a temporary file and return its path $tmp = tempnam('/tmp', 'PHP'); // Get the file token key $key = ftok($tmp, 'a'); // Attach the SHM resource, notice the cast afterwards $id = shm_attach($key); if ($id === false) { die('Unable to create the shared memory segment'); } // Cast to integer, since prior to PHP 5.3.0 the resource id // is returned which can be exposed when casting a resource // to an integer $id = (integer) $id; ?>

Смотрите также

shm_detach() - Disconnects from shared memory segment
ftok() - Convert a pathname and a project identifier to a System V IPC key