shm_attach
PHP function
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(PHP 4, PHP 5, PHP 7, PHP 8)
Creates or open a shared memory segment
Description
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.
Parameters
keyA numeric shared memory segment ID
sizeThe memory size. If not provided, default to the
sysvshm.init_memin the Ini, otherwise 10000 bytes.permissionsThe optional permission bits. Default to 0666.
Return Values
Returns a SysvSharedMemory instance on success, Falseforfailure.
Changelog
| 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. |