shmop_close doesn't delete the memory segment, it just detaches from it.
If you have created the block and need to delete it you must call shmop_delete **BEFORE** calling shmop_close (for reasons outlined in shmop_delete help page notes).
(PHP 4 >= 4.0.4, PHP 5, PHP 7, PHP 8)
shmop_close — Cerrar un segmento de memoria compartida
shmop_close() se utiliza para cerrar un segmento de memoria compartida.
No devuelve ningún valor.
Ejemplo #1 Cerrando segmento de memoria compartida
<?php
shmop_close($shm_id);
?>
Este ejemplo cierra un segmento de memoria compartida identificado por $shm_id.
shmop_close doesn't delete the memory segment, it just detaches from it.
If you have created the block and need to delete it you must call shmop_delete **BEFORE** calling shmop_close (for reasons outlined in shmop_delete help page notes).As explained on this page, PHP 8.0.0 expects a Shmop instance instead of a resource. According to bug #81098 this change means that the Shmop closes itself when the script completes so there is no need to close it with shmop_close.
Using function_exists('shmop_close') will return true but calling shmop_close will throw a deprecation error.
The documentation explains the change in 8.0.0 expects the expected argument changed without mentioning it'll just throw a deprecation error.