SEARCH KEYWORD -- Code standard


  How DNS lookup works

When accessing a website, a domain name would be needed normally. To get to the actual web server, the domain name must be mapped to an actual IP address and the IP address will be used to reach the web server. The process of finding the IP address from a domain name is called DNS lookup.  How does DNS lookup work? There are tons of domain name and IP address around the world, there must be some well-designed architecture to support fast lookup. This post will explain how this works. DNS Se...

   DNS,DNS LOOKUP     2022-09-09 23:11:03

  Performance comparison of string concatenation in Go language

In Go language, string concatenation is an inevitable operation during development, and efficient string concatenation is crucial for improving application performance. This article will delve into several common ways of string concatenation, provide performance comparisons, and offer optimization suggestions aimed at helping developers write more efficient code. Common ways of string concatenation In Go language, common ways of string concatenation include the following: Using the + operator fo...

   COMPARISON,PERFORMANCE,STRING CONCATENATION     2024-05-13 00:33:20

  Introduction to the Application of eBPF in Golang

Most of the time, when we develop software or even use software, we play within the safe boundaries of the operating system. We might not know how the network interface welcomes that IP packet, nor how the filesystem handles the inodes when we save a file. This boundary is called user space, which is where we write applications, libraries, and tools. But there's another world, kernel space, where the operating system's kernel resides and is responsible for managing system resources such as memor...

   EBPF,GOLANG,GUIDE,APPLICATION     2024-10-02 08:46:37

  Unix directory hierarchy history

As a beginner user of Unix or Linux, people would frequently get confused about the use of different directories of the system.  For example, there is a /bin directory under root(/), it is used to store binary files. However, there are /usr/bin and /usr/local/bin under /usr which are used for storing binary files as well. Some systems even have /opt/bin. What are the differences among them? Though there are articles explaining different directories in *nix such as Filesystem Hierarchy Stan...

   UNIX,LINUX,FILESSYTEM,DIRECTORY HIERARCHY,HISTORY     2016-10-21 23:47:17

  How to make select in WinSock exceed the 64-socket limit

When doing cross-platform network programming, the only API available on Windows that corresponds to the epoll/kevent style reactor event model is select. However, it has a limitation: the number of sockets passed into select cannot exceed FD_SETSIZE, which is set to 64. Therefore, select in Java’s NIO on Windows also has the same limit. Many services ported to Windows that use the reactor model face this constraint, which often gives the impression that server programs on Windows hav...

   EXCEED,SELECT,JAVA,WINDOWS     2024-10-31 23:47:50

  The 9 lines of code of Google

Are you still remembering the then hot debated news about Oracle suing Google allegedly copying a small portion of codes from Oracle's Java in 2010. At that time, Oracle experts estimated that Google owes Oracle between $1.4 billion and $6 billion in damages if liable. But the court thought Oracle was eligible only for statutory damages for that copying, which were not expected to exceed a few hundred thousand dollars. At last, Oracle agreed the zero damage result. Are you curious about whi...

   Google,Java,Open source     2014-08-15 20:29:52

  Art of code comment

Note : This post is just for fun. Please be careful about these tricks. Code comment is to provide complementary comment to abstract codes. We will introduce two comment styles while we are debugging our codes. we should avoid these styles in production codes. 1. if else style Only execute eatKfc() //* eatKfc(); /*/ eatMcdonalds(); //*/ Only execute eatMcdonalds() /* eatKfc(); /*/ eatMcdonalds(); //*/ Execute both //* eatKfc(); //*/ eatMcdonalds(...

   Comment,Style     2013-08-19 04:19:40

  Why cannot compare double values directly for equality?

A question in PHP: Get some value from the database and use floatval() to convert it to floatint point value, then compare it with another value which is also converted to floating point value with floatval(). These two values are the same when using var_dump() to output, the two outputs are float(8.87), they are the same. But when comparing them for equality, the result is weird., they are not equal. Why?To analyze this question, we need to start with PHP data types. PHP uses weak types. In PHP...

   PHP,floating, precision,compare,equality     2012-06-27 09:01:36

  What and what not to log while debugging

Log is a critical part of an application. It serves as an eye to the programmer on how the application is working while debugging. Especially for applications running on production environment, if the application encounters problem and the problem cannot be reproduced on other environments, log will be extremely useful. While log is essential, but developers have to log smartly. Because if don't put log smartly, you may not get what you want while debugging or you may get too many...

   PROGRAMMING,DEBUG,LOG,SUPPORT     2016-03-14 08:09:03

  A trap about PHP random number

The method to get random number in PHP is very simple, we only need to use rand() function. int rand ( int $min , int $max ) One function call can return the random number in a specified range. But in fact, the random number in computer is actually pseudorandomness, generally to increase the randomness, we may set a random seed before calling rand(). void srand ([ int $seed ] ) According to other language features, we should pass a time value as a parameter to the srand() function, generally...

   PHP,rand,srand,mt_rand     2013-06-07 09:10:10

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