shmop_read

(PHP 4 >= 4.0.4, PHP 5, PHP 7, PHP 8)

shmop_read — Read data from shared memory block

说明

shmop_read(Shmop $shmop, int $offset, int $size): string

shmop_read() will read a string from shared memory block.

参数

shmop

The shared memory block identifier created by shmop_open()

offset

Offset from which to start reading; must be greater than or equal to zero and less than or equal to the actual size of the shared memory segment.

size

The number of bytes to read; must be greater than or equal to zero, and the sum of offset and size must be less than or equal to the actual size of the shared memory segment. 0 reads shmop_size($shmid) - $start bytes.

返回值

Returns the data.

错误／异常

If offset or size are out of range, a ValueError is thrown.

更新日志

版本 说明
8.0.0 shmop expects a Shmop instance now; previously, a resource was expected.
8.0.0 If offset or size are out of range, a ValueError is thrown; previously E_WARNING was emitted, and false was returned,

示例

示例 #1 Reading shared memory block

<?php
$shm_data = shmop_read($shm_id, 0, 50);
?>

This example will read 50 bytes from shared memory block and place the data inside $shm_data.

参见