ipc | 易学教程

How do you communicate between Windows Vista Session 0 and Desktop?

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问题 In prior versions of Windows before Vista you could have a Windows Service interact with the current logged in desktop user to easy display information on the screen from the service. In Windows Vista Session 0 was added for security to isolate the services from the desktop. What is an easy way to communicate between a service and an application running outside of Session 0? So far I have gotten around this by using TCP/IP to communicate between the two but it seems to be kind of a sloppy way

Implementing a message bus using ZeroMQ

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问题 I have to develop a message bus for processes to send, receive messages from each other. Currently, we are running on Linux with the view of porting to other platforms later. For this, I am using ZeroMQ over TCP. The pattern is PUB-SUB with a forwarder. My bus runs as a separate process and all clients connect to SUB port to receive messages and PUB to send messages. Each process subscribes to messages by a unique tag. A send call from a process sends messages to all. A receive call will

sys v shared memory from kernel module to user space process

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问题 i am new in linux kernel module developpement and i am searching for sharing a memory segment from kernel module to user space process to escape latency of copying data. i am using the sys v shared memory api, when i share memory between two process it's work fine, but i am not able to share memory between process and kernel module. bellow is my code of the kernel module and the user space app server side : module #include <linux/module.h> // init_module, cleanup_module // #include <linux

Softwaredevelopment patterns for Files and Caches as Inter-Process-Communication

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问题 To work with databases or files as simple data persistance layer is easy to understand. But there are also ways to use them as communication channel to transfer data from one running process to another one or even send commands and requests, especially when this channel is faster then normal Unix sockets, like shared memory. But how do you use this efficiently? I mean, a process doesn't get an Event for a change in shared memory, he always has to poll for it, right? But isn't that too

Call a function from a running process

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问题 my programm starts a subprocess, which has to send some kind of signal to the parent after initialization. It would be perfekt if i could set up a handler in parent, which is called when this signal is sent. Is there any way to do it? Alendit 回答1: If you are using Python 2.6, you can use the multiprocessing module from the standard library, in particular pipes and queues. Simple example from the docs: from multiprocessing import Process, Pipe def f(conn): #This code will be spawned as a new

Shared memory C++ - PHP

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问题 I am trying to create a shared memory segment in a C++ app. Then read it back on a web page. The C++ app will be the server. And my test code works with the shm_client.c example on this page. C++ code: key = 6565; if( (shmid = shmget( key, 27, IPC_CREAT | 0666 )) < 0 ) throw std::string( "shmget failed." ); if( (data = shmat( shmid, NULL, 0 )) < 0 ) throw std::string( "shmat failed" ); memset( data, 0, 27 ); strncpy( (char *)data, "Hello world", 27 ); I changed the key in shm_client.c to 6565

How to make cloned DOM element JSON serializable

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问题 I'm currently working with GitHub's Electron framework, and I'm trying to send a cloned DOM element from a preloaded script in a webview through their IPC messaging system to my renderer process. Though, DOM elements are not able to be converted to JSON, and thus the received message is printing out an empty Object ( Object {} ). Here's my code: Preload.js var ipc = require("electron").ipcRenderer; function getData(element, trait){ if(trait === "id"){ var elem = document.getElementById

Passing a reference to a COM object accross processes via IPC?

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问题 I have a reference to a COM object, and would like to pass that reference on to another process. So, I'd need some way to serialize information about this reference that would allow me to restore it again in the other process. Is there any way to do this for COM objects of any arbitrary type? I'm don't know too much about COM; from what I understand, there may be Monikers for some types of objects (for example, COM references such as Excel.Workbook might be restored via their .FullName

how to make client to check if the server is done with read operation from pipe before writing data into pipe in c++

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问题 I need my client to first check if server is reading data from pipe, if yes then wait till server is done else write data into pipe. If I don't use sleep command in my sample client program then Server doesn't read message properly.I found the reason of this issue from the documentation it says: This buffer must remain valid for the duration of the read operation. The caller must not use this buffer until the read operation is completed. But it doesn't specify how to block client until the

分布式系统

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第一章分布式计算定义：分布式计算是研究把一个需要非常巨大的计算能力解决的问题分成许多小的部分，然后把这些部分分配给许多计算机进行处理，最后把各部分的计算结果合并起来得到的最终成果（分而治之）。分布式计算的优缺点：优点： 1、低廉的计算机价格和网络访问的可用性 2、资源共享 3、可伸缩性 4、容错性缺点： 1、多点故障 2、安全性低分布式计算的相关形式： 1、单机计算：利用单台计算机进行计算，此时计算机不与任何网络连接，因而只能使用本计算机系统内可被即时访问的所有资源。 2、并行计算：采用多个处理器来执行单个指令。并行计算是指同时使用多种计算资源解决计算问题的过程，是提高计算机系统计算速度和处理能力的一种有效手段。 3、网络计算：网络计算的概念较宽泛。网络计算的核心思想是，把网络连接起来的各种自治资源和系统组合起来，以实现资源共享、协同工作和联合计算，为各种用户提供基于网络的各类综合性服务。 4、网格计算：利用互联网把地理上广泛分布的各类资源（计算、存储、宽带、软件、数据、信息、知识等）连成一个逻辑整体，就像超级计算机，为用户提供一体化信息和应用服务（计算、存储、访问）。 5、云计算：这个概念是由Google公司提出。云计算是一种资源交付方式，使用虚拟化技术为核心。云计算的主要形式包括基础设施即服务（IaaS）、平台即服务（PaaS）和软件即服务（SaaS）。