(PHP 4, PHP 5, PHP 7)
shm_attach — Creates or open a shared memory segment
shm_attach ( int $key [, int|null $size = null [, int $permissions = 0666 ]] ) : SysvSharedMemory|false
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.
key
A numeric shared memory segment ID
size
The memory size. If not provided, default to the sysvshm.init_mem in the php.ini, otherwise 10000 bytes.
permissions
The optional permission bits. Default to 0666.
Returns a SysvSharedMemory instance on success, or false on failure.
| Version | Description |
|---|---|
| 8.0.0 | On success, this function returns an SysvSharedMemory instance now; previously, a resource was returned. |
| 8.0.0 | size is nullable now. |
© 1997–2020 The PHP Documentation Group
Licensed under the Creative Commons Attribution License v3.0 or later.
https://www.php.net/manual/en/function.shm-attach.php