简介

This module provides wrappers for the System V IPC family of functions. It includes semaphores, shared memory and inter-process messaging (IPC).

Semaphores may be used to provide exclusive access to resources on the current machine, or to limit the number of processes that may simultaneously use a resource.

This module provides also shared memory functions using System V shared memory. Shared memory may be used to provide access to global variables. Different httpd-daemons and even other programs (such as Perl, C, ...) are able to access this data to provide a global data-exchange. Remember, that shared memory is NOT safe against simultaneous access. Use semaphores for synchronization.

The messaging functions may be used to send and receive messages to/from other processes. They provide a simple and effective means of exchanging data between processes, without the need for setting up an alternative using Unix domain sockets.

注意: 本扩展模块在 Windows 平台下不可用。

需求

要编译本扩展模块无需外部库文件。

安装

Support for this functions are not enabled by default. To enable System V semaphore support compile PHP with the option --enable-sysvsem. To enable the System V shared memory support compile PHP with the option --enable-sysvshm. To enable the System V messages support compile PHP with the option --enable-sysvmsg.

运行时配置

这些函数的行为受 php.ini 的影响。

资源类型

预定义常量

以下常量由本扩展模块定义，因此只有在本扩展模块被编译到 PHP 中，或者在运行时被动态加载后才有效。

目录

ftok Convert a pathname and a project identifier to a System V IPC key

msg_get_queue Create or attach to a message queue

msg_receive Receive a message from a message queue

msg_remove_queue Destroy a message queue

msg_send Send a message to a message queue

msg_set_queue Set information in the message queue data structure

msg_stat_queue Returns information from the message queue data structure

sem_acquire Acquire a semaphore

sem_get Get a semaphore id

sem_release Release a semaphore

sem_remove Remove a semaphore

shm_attach Creates or open a shared memory segment

shm_detach Disconnects from shared memory segment

shm_get_var Returns a variable from shared memory

shm_put_var Inserts or updates a variable in shared memory

shm_remove_var Removes a variable from shared memory

shm_remove Removes shared memory from Unix systems