CIV. Shared Memory Functions

简介

Shmop is an easy to use set of functions that allows PHP to read, write, create and delete Unix shared memory segments.

注: Versions of Windows previous to Windows 2000 do not support shared memory. Under Windows, Shmop will only work when PHP is running as a web server module, such as Apache or IIS (CLI and CGI will not work).

注: In PHP 4.0.3, these functions were prefixed by shm rather than shmop.

需求

无需外部库文件就可以加入本扩展模块的支持。

安装

To use shmop you will need to compile PHP with the --enable-shmop parameter in your configure line.

运行时配置

该扩展模块未定义任何设置指令。

资源类型

预定义常量

该扩展模块未定义任何常量。

例

例子 1. Shared Memory Operations Overview

<?php // Create 100 byte shared memory block with system id if 0xff3 $shm_id = shmop_open(0xff3, "c", 0644, 100); if (!$shm_id) { echo "Couldn't create shared memory segment\n"; } // Get shared memory block's size $shm_size = shmop_size($shm_id); echo "SHM Block Size: " . $shm_size . " has been created.\n"; // Lets write a test string into shared memory $shm_bytes_written = shmop_write($shm_id, "my shared memory block", 0); if ($shm_bytes_written != strlen("my shared memory block")) { echo "Couldn't write the entire length of data\n"; } // Now lets read the string back $my_string = shmop_read($shm_id, 0, $shm_size); if (!$my_string) { echo "Couldn't read from shared memory block\n"; } echo "The data inside shared memory was: " . $my_string . "\n"; //Now lets delete the block and close the shared memory segment if (!shmop_delete($shm_id)) { echo "Couldn't mark shared memory block for deletion."; } shmop_close($shm_id); ?>

目录
shmop_close -- Close shared memory block
shmop_delete -- Delete shared memory block
shmop_open -- Create or open shared memory block
shmop_read -- Read data from shared memory block
shmop_size -- Get size of shared memory block
shmop_write -- Write data into shared memory block

add a note User Contributed Notes
Shared Memory Functions

slavapl at mailandnews dot com
12-Jan-2001 07:02

What you need to realise is that sysvshm is extremly php oriented in it's
ability, it's quite a kludge interfacing other NON PHP utilities with it.
For example have you tried using sysvshm to read an shm segment NOT created
by php? It's not possible, because sysvshm uses a proprietry format, in
essense it can ONLY be used within PHP unless of course you take time to
figure out this format. 

So basically, the purpose of shmop is to
provide a symple interface to shared memory that can be used with OTHER NON
php shm creators. 



Hope this clears it up.

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