In this tutorial, we’ll discuss how to get the details of a POSIX message queue from the command line. Firstly, we’ll learn about message queues. Then, we’ll look at an example of a POSIX message queue and see how to get the details. 2. Brief Information About Message Queues A m...
一、什么是消息队列 消息总线(Message Queue),后文称MQ,是一种跨进程的通信机制,用于上下游传递消息。是一种非常常见的上下游“逻辑解耦+物理解耦”的消息通信服务。 二、应用场景 场景一:上游不关心下游执行结果(订单状态改变,发邮件) 1)上游执行时间短 2)上下游逻辑+物理解耦,除了与MQ有物理连接,模块之间都不...
比较常用的我们会涉及到message queue,sharememory,semaphore,socket,signal等。semaphore是共享资源互斥的方法,其他都是冗余的方式进行通信。互斥是个比较复杂的话题,我们单开一节讨论一下。 共享资源的互斥 为什么要保护共享资源做互斥访问,这里不罗嗦了。通过对共享资源(临界区)加锁可以实现互斥访问,互斥锁(mutex)也有...
An in-depth description of PMPthread internal queue functions. Examples Pthreads tutorial and examples of thread problems- by Andrae Muys Valgrind KDE thread checker: Helgrind Sun's Multithreaded Programming Guide- Not Linux but a good reference. ...
### 1 step: build and install OpenCV 4.1.2 (4c71dbf)## https://docs.opencv.org/master/d7/d9f/tutorial_linux_install.html## https://opencv.org/releases/#cd /opt/<my_working_directory>### 1 step: apt insall depend libs#libopencv-devsudoecho"deb http://security.ubuntu.com/ubuntu...
RabbitMQ, Beanstalk, Redis and Kombu as message queue Task priority, retry, periodical, recrawl by age, etc... Distributed architecture, Crawl Javascript pages, Python 2&3, etc... Tutorial: http://docs.pyspider.org/en/latest/tutorial/ Documentation: http://docs.pyspider.org/ Release notes:...
### 1 step: build and install OpenCV 4.1.2 (4c71dbf)## https://docs.opencv.org/master/d7/d9f/tutorial_linux_install.html## https://opencv.org/releases/#cd /opt/<my_working_directory>### 1 step: apt insall depend libs#libopencv-devsudoecho"deb http://security.ubuntu.com/ubuntu...
### 1 step: build and install OpenCV 4.1.2 (4c71dbf) ## https://docs.opencv.org/master/d7/d9f/tutorial_linux_install.html ## https://opencv.org/releases/ # cd /opt/<my_working_directory> ### 1 step: apt insall depend libs # libopencv-dev sudo echo "deb http://security....