(PHP 4, PHP 5)
shm_attach — Creates or open a shared memory segment
resource shm_attach ( int $key [, int $memsize [, int $perm ]] )
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.
Returns a shared memory segment identifier.