PHP Manual: shmop

function shmop_write(Shmop $shmop, string $data, int $offset): int

shmop_write() will write a string into shared memory block.

shmop: The shared memory block identifier created by shmop_open()
data: A string to write into shared memory block
offset: Specifies where to start writing data inside the shared memory segment. The offset must be greater than or equal to zero and less than or equal to the actual size of the shared memory segment.

The size of the written data.

If offset is out of range, a ValueError is thrown. If the shared memory segment was opened read-only, an Error is thrown.

Version	Description
8.0.0	Prior to PHP 8.0.0, `false` was returned on failure.
8.0.0	`shmop` expects a Shmop instance now; previously, a resource was expected.

Example #1 Writing to shared memory block

<?php
$shm_bytes_written = shmop_write($shm_id, $my_string, 0);
?>

This example will write data inside $my_string into shared memory block, $shm_bytes_written will contain the number of bytes written.

shmop_write