shm_attach
Name
shm_attach — Attaches to a shared memory segment,
creating it if necessary.
Synopsis
int shm_attach(key[, memsize][, permissions]);
int key: Unique key for the
script's shared memory segment
int memsize (optional): Size
of the shared memory segment, in bytes
int permissions (optional):
Permissions for the shared memory segment
Returns
Shared memory ID on success; FALSE on failure
Description
shm_attach() takes as its first argument a key
that it uses to identify the shared memory segment to
which you want to attach. Any process can use the same
key to attach to this segment, which allows the sharing
of the memory. It's a good idea to attempt to make this
key unique to the scripts that will be using it, so as
not to conflict with other programs that might use the
same key.
If supplied, memsize denotes
the number of bytes of storage that will be allocated for
the shared memory segment. If not given, the value will
be that given by the sysvshm.init_mem option in
php.ini, or 100000 if
sysvshm.init_mem isn't specified.
If supplied, permissions sets
the permissions on the shared memory segment, which are
expressed in the same fashion as UNIX filesystem
permissions. This is usually given in octal, and defaults
to 0666.
Version
PHP 3 since 3.0.6, PHP 4
Example
Example 1173. Attach to a
shared memory segment
if (!$shm_id = @shm_attach(2000, 10000, 0600)) {
echo "Could not attach to shared memory; reason: $php_errormsg.\n";
}
PHP Functions Essential Reference. Copyright © 2002 by New Riders Publishing
(Authors: Zak Greant, Graeme Merrall, Torben Wilson, Brett Michlitsch).
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