How can shared memory be locked in php (shmop) -

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please how can shared memory created in php using shmop (not shm if matters) locked , unlocked? require libraries?

it seems shmop_read() runs while shmop_write() still writing because value read has part of old , new values.

you cannot explicity lock shared memory segment, can open in exclusive mode, e.g.

shmop_open($shm_key, "n", 0644, 100);

quoting http://www.php.net/manual/en/function.shmop-open.php

"n" create new memory segment (sets ipc_create|ipc_excl) use flag when want create new shared memory segment if 1 exists same flag, fail. useful security purposes, using can prevent race condition exploits.


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