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shmop series functions use PHP shared memory implementation method

Mar 08, 2018 am 10:51 AM
php shmop shared

Shmop, is an easy-to-use feature set that allows PHP to read, write, create and delete UNIX shared memory segments. This article mainly shares with you the implementation method of shmop series functions using PHP shared memory. I hope it can help you.

1、shmop 系列函数使用


<?php
//使用shmop 系列函数
set_time_limit(0);
$shm_key = ftok(__FILE__, &#39;t&#39;);
$shm_id = shmop_open($shm_key, "c", 0655, 1024);
$size = shmop_write($shm_id, "Hello world".PHP_EOL, 0);
shmop_write($shm_id, &#39;I love you&#39;.PHP_EOL, $size+1);
echo $size.PHP_EOL;
$data = shmop_read($shm_id, 0, 100);
var_dump($data);
shmop_delete($shm_id);
shmop_close($shm_id);


//Shared Memory Functions


/**
 * shmop_open(int $key , string $flags , int $mode , int $size)
 * $key 共享内存的key
 * $flags 的值有以下几种
 * a :  创建一个只读的共享内存区。
 * c :  如果共享内存区已存在,则打开该共享内存区,并尝试读写。否则新建共享内存区
 * w : 创建一个读写共享内存区
 * n :  创建一个共享内存区,如果已存在,则返回失败
 *
 * $mode 读写权限。如0755 0644 等
 * $size 申请共享内存区的大小
 */


/**
 * shmop_read( resource $shmid , int $start , int $count)
 * 将从共享内存块中读取数据
 * $shmid 共享内存id,资源类型
 * $start 从共享内存的那个字节开始读起
 * $count 一次读取多少个字节。
 * 如果count值小于发送的信息长度,则信息会被截断。
 */


/**
 * shmop_write(resource $shmid , string $data , int $offset)
 * 将数据写入共享内存块
 * $data 将要写入的数据
 * $offset 从共享内存块的那个位置开始写入。
 * 该函数的返回值是写入数据的长度。
 */


/**
 * shmop_size(resource $shmid);
 * 返回当前共享内存块,已经使用的大小
 */




/**
 * shmop_delete ( resource $shmid )
 * 删除一个共享内存块的,删除引用关系
 */


/**
 * shmop_close ( resource $shmid )
 * 关闭共享内存块
 * 要先使用shmop_delete 之后才能继续使用shmop_close
 */
2、shm 系列函数使用


<?php
//使用信号量扩展共享内存
$key = ftok(__FILE__, &#39;a&#39;);
$share_key = 1;


//创建一个共享内存,大小为1024字节,权限为755
$shm_id = shm_attach($key, 1024, 0755);


//将一个key=>value放进共享内存
$message1 = "I love Roverliang";
shm_put_var($shm_id, $share_key, $message1);


//重复使用key ,前一个设置的值会被后一个设置的值覆盖掉。
$message2 = "I love Rover";
shm_put_var($shm_id, $share_key, $message2);


//读取一个共享内存值
$read_message = shm_get_var($shm_id, $share_key);
echo $read_message.PHP_EOL;


//并不是取走了,而是读取
$read_message2 = shm_get_var($shm_id, $share_key);
echo $read_message2.PHP_EOL;


//判断共享内存中,某个值是否存在
$isexists = shm_has_var($shm_id, $share_key);
var_dump($isexists);


//删除一个值
shm_remove_var($shm_id, $share_key);


//判断共享内存中,某个值是否存在
$isexists = shm_has_var($shm_id, $share_key);
var_dump($isexists);


//删除一个共享内存
shm_remove($shm_id);


//关闭共享内存的连接
shm_detach($shm_id);
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Related recommendations:

Detailed explanation of the use of PHP shared memory

The use of PHP shared memory

A preliminary study on php shared memory shmop

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