• Difference between static and dynamic memory allocation


    Static allocation, local variable allocation. Once allocated, the memory size is fixed and cannot be changed. It will be allocated during compilation and linking. Dynamic allocationIt refers to the method of dynamically allocating or reclaiming storage space and allocating memory in the process of program execution. Dynamic memory allocation is made by the system according […]

  • The function of closure and its advantages and disadvantages


    In interview questions, closure should be a must ask question (the following content is purely personal understanding, welcome to correct the lack) Let’s take a brief look at what a closure is   First of all, let’s talk about closures In short, it is a function defined in the function, which can read other functions’ […]

  • “Trick” of packing and unpacking


    I. stereotype value type and reference type   As we all know, the. Net type system consists ofClasses, structures, enumerations, interfaces, and delegatesForm. According to the way of memory allocation, all types are divided intoValue typeAndreference type。   When it comes to value type, most people will confidently say, “value type is not int, float, double… […]

  • The ultimate solution to the problem of IIS error reporting of Web site publisher


          4This error occurs after WebService publishes a new server. resolvent:   DMP file found What is a DMP file? Own Baidu. In short, it’s the black box. It records the operation before the program crashes. How to find the black box? 1. Start the windows error reporting service   2. Execute the […]

  • [original] (IX) Linux memory management – zoned page frame allocator – 4


    background Read the fucking source code!–By Lu Xun A picture is worth a thousand words.–By Golgi Explain: Kernel version: 4.14 Arm64 processor, contex-a53, dual core Using tool: source insight 3.5, Visio 1. overview This article will describememory compaction, memory defragmentation technology.Memory fragments are divided into internal and external fragments: Internal fragment: the fragment inside the […]

  • ==Difference with equals


    1. For basic data types (such as int), = = can be used to compare whether their values are equal; for encapsulation types (such as string, integer), = = is used to compare whether their addresses in memory are consistent. 2. Equals is an object method, such as string.equals (string example), which is used to […]

  • Count the slots in SharedPreferences!


    Preface Recently, when dealing with a historical legacy project, it suffered a lot, mainly manifested in the occasional data disorder or even loss of the SharedPreferences configuration file. After investigation, it was found that it was a multi process problem. There are two different processes in the project, and the SharedPreferences file is read and […]

  • Java code execution process overview


    Java code has three phases: source – > classloader – > runtime.        First of all, let’s clear up the whole execution process of Java code, let’s have a whole understanding of it: Java source(. Java) processJava compilerAfter (javac), generate one or moreBytecode(. Class) file,JVMEvery item to be executedBytecodeadoptClassloaderLoad into memory, and then passbytecode verifier […]

  • Memcached source code analysis – slab


    As a memory management scheme, slab has the following two functions: A) avoid memory fragmentation caused by frequent memory allocation and release B) reduce performance overhead caused by memory allocation operations There is also a slab design in the Linux kernel data structure. Linux provides a set of interfaces that can be used to dynamically […]

  • Development of UHF reader under Android


    With the use of UHF reader and writer on Android devices becoming more and more extensive, youI technology independently developed the Android development package of UHF reader and writer. With this development package, engineers can easily develop the UHF reader and writer application app under Android by importing jar package in the project and using […]

  • Linux view CPU and memory MEM usage of specified process


    Although the top command can see the real-time process resource utilization, it is a list of all processes. Sometimes it is not suitable or convenient, so this script is written to filter the resource utilization of the specified process. #Keep loop, keep output while true; do #Combination of two commands #Command 1: PS command pipeline […]

  • Rethinking the Java static keyword


    The Java class, while also wrote a lot of Java code, but there has been a lot of doubt, the static keyword has puzzled me for a long time, today didn’t mean to study, on zhihu check again carefully and found the best answer to the topic of https://www.zhihu.com/question/36615154 This article thoroughly understanding of the […]