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 size and the optional perm-bits permissions.
A second call to shm_attach for the same key will return a different SysvSharedMemory instance, but both instances access the same underlying shared memory. size and permissions will be ignored.
A numeric shared memory segment ID
The memory size. If not provided, default to the sysvshm.init_mem in the php.ini, otherwise 10000 bytes.
The optional permission bits. Default to 0666.
Returns a SysvSharedMemory instance on success, or false on failure.
|8.0.0||On success, this function returns an SysvSharedMemory instance now; previously, a resource was returned.|
|8.0.0||size is nullable now.|