PHP Functions Essential Reference

shm_attach

int shm_attach(int key, [int memsize], [int permissions])

key	Unique key for the script’s shared memory segment
memsize	Size of the shared memory segment, in bytes
permissions	Permissions for the shared memory segment

Attaches to a shared memory segment, creating it if necessary.

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. ...