• Three methods to modify the limit of open files in Linux


    When a file is opened for access, the operating system temporarily assigns a number called file handle. A special area of main memory is reserved for file handles. The size of this area determines how many files can be opened at a time. Processes on Linux are subject to many restrictions, which also prevent them […]

  • PHP rar decompression read expansion pack learning


    As the extended learning of compression and decompression, the two ace compression formats RAR and zip have always been the compression terminators in the computer field. Rar compressed packages are nearly dominant in the windows system. The PHP extension we are learning today is aimed at rar compressed package operation. However, the RAR extension of […]

  • Rocksdb code parsing – dB. H


    total   This article is an analysis of the overall function of rocksdb, mainly focusing on the DB. H file,To analyze the code of rocksdb, if you want to understand its function in an overall way, you should first parse the DB. H file. For the DB. H file of rocksdb, regardless of the previous string […]

  • C #. Exe and. DLL file icon resource extraction tool


    Windows executable (. Exe) and dynamic library (. DLL) icon resource extraction tool GitHub function Icon resource Preview Icon resource export (only PNG format is supported) code The Win32 API is used to get the icon resourcePrivateExtractIconsW C# code corresponding to privateextracticonsw [DllImport(“User32.dll”)] internal static extern uint PrivateExtractIcons( /* _In_reads_(MAX_PATH) */ string szFileName, /* _In_ […]

  • How to create and modify CAD drawings through JavaScript at the front end


    background In previous blog postsAnalysis and summary of WebGIS visualization technology for DWG analysis of CAD drawings、CAD_ DWG map web visualization one-stop solution – Weijie map – vjmapIt explains how to visualize drawings in DWG format of CAD on the web. Can you create them through JavaScript or modify them based on current CAD graphics […]

  • Selenium window switching


    When browsing the web, sometimes clicking a link or button will pop up a new window. Use selenium for web automation test. If a new window pops up without switching the window, then,Webdriver objectThe focus of is still the old window. Subsequent automation operations will continue in the old window. Example verification: #Simulation scenario: open […]

  • Learn directory operations in PHP


    For programming languages, the operation of files and directories is the most basic function. Like the most common image upload and file upload functions in our daily life, we need the support of file and directory operation. Today, let’s briefly learn some classes and functions about directory operation in PHP. Directory and path separator First, […]

  • Learn how to use the FileInfo extension in PHP


    Today’s extension is actually a standard extension. Why? Because the laravel framework is a necessary extension when it is installed. If it is not opened, even the laravel framework cannot be used. Introduction to FileInfo FileInfo is to obtain the content type and code of the file through the given magic byte sequence library. The […]

  • File system functions in PHP (3)


    Finally, we come to the part we are most concerned about, that is, the operation of f-related functions. Basically, most of the file operations are based on the contents learned today. Let’s learn one by one. File reading The file reading is actually very simple. Fopen () opens the handle, FREAD () reads the content, […]

  • How does deep decryption epoll work?


    Epoll is a unique implementation of multiplexing io on Linux platform. Compared with the traditional select, epoll has a great improvement in performance. This article mainly explains the implementation principle of epoll, and for the use of epoll, you can refer to relevant books or articles.Relevant video recommendationsDuring the interview, I was serious about the […]

  • JS events – add and remove events


    element.addEventListener(event, function, useCapture)   Method to add an event handle to the specified element.   Event: required. String specifying the event name.be careful:  For example, use “click” instead of “onclick”.   Function: trigger function   Usecapture: optional. Boolean value that specifies whether the event is executed during the capture or bubble phase. Possible values: True – the […]

  • [rtthread learning notes series] Part 1: timer


    1、 Timer concept1.1 clock beat Clock beat is the smallest time unit of the system, macro RT_ TICK_ PER_ When the second is 100, the time of a clock beat is 10ms, and the clock beat is also the smallest unit of thread time slice. In STM32, the clock beat is realized through systick interrupt. […]