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  Python internals: adding a new statement to Python

This article is an attempt to better understand how the front-end of Python works. Just reading documentation and source code may be a bit boring, so I’m taking a hands-on approach here: I’m going to add an until statement to Python. All the coding for this article was done against the cutting-edge Py3k branch in the Python Mercurial repository mirror. The until statement Some languages, like Ruby, have an until statement, which is the complement to while (until num == 0 is equi...

   Python,New statement,Research,Addition     2012-03-12 07:32:24

  WireGuard VPN Troubleshooting

When you are working as a network/cluster admin for you team to config the WireGuard VPN for other members, you may meet some of the problems below and these are the solution you can try to fix them. ----------------------------------------------------------------------------------------------------------- Problem [1]: The WireGuard handshake request send from the client can be received from the server but the server's response was blocked at some where so the client can not receive serv...

   WIREGUARD,VPN,TROUBLESHOOTING     2021-12-14 09:17:46

  An experience of fixing a memory-corruption bug

During the last 4 months, I was disturbed by a memory-corruption bug, and this bug will cause program crash. Until last Monday, I found the root cause and fixed it. This debug process is a difficult but memorable experience, so I will share it in this article.   My program works as a SMS Hub. When it receives a SMS, it will allocate a structure in heap memory like this: typedef struct { ...... int *a[8]; ...... } info; After processing the SMS, the program will free the m...

   c, debug, unix, solaris, multi-thread     2014-05-04 03:52:43

  Go vs C benchmark. Could Go be faster than C?

During last semester I was attending Multiprocessor Architectures course, given at Facultad de Informática where I study my Computer Science degree. As part of the assignments due to pass the course, we had to do several programs written in C to benchmark matrix multiplication by testing different techniques and technologies. First of all we had to do a secuential program in three different versions: A normal one where the result matrix is ordered by rows and the loops range the matrix by ...

   Gp,C,Benchmark,Faster,Speed,Comparison     2012-02-08 10:09:07

  Bash Shell Scripting - 10 Seconds Guide

This Bash shell scripting guide is not a detailed study but a quick reference to the BASH syntax. So lets begin... Common environment variables PATH - Sets the search path for any executable command. Similar to the PATH variable in MSDOS. HOME - Home directory of the user. MAIL - Contains the path to the location where mail addressed to the user is stored. IFS - Contains a string of characters which are used as word seperators in the command line. The string normally consists of the spac...

   Bash,Shell,Linux,Tutorial,10 seconds,Shortcut key     2012-02-28 08:05:41

  Why accessing Java HashMap may cause infinite loop in concurrent environment

HashMap in Java is frequently used to handle key/value pairs. But it is not a good candidate to be used in concurrent environment where ConcurrentHashMap should be used instead. If used in concurrent environment, it may cause lots of unexpected behavior even including make the program getting into an infinite loop situation. To understand how this can happen, let's first discuss how HaspMap works internally. In this post we will use implementation of HashMap before Java 8 as example, Java 8 prov...

   JAVA,HASHMAP,INFINITE LOOP     2020-03-29 01:47:00

  Use of log in programming

Usually, The purposes of log are for troubleshooting and displaying program running status. Good log will help us locate the error easier. Many programmers think log in programs is very simple, but it's not an easy task to write log codes to efficiently locate the error. Here we discuss about program log in three aspects: Where to log What to log Log styles to be avoided Where to log 1. When calling external functions When your program is calling some external functions which are not written b...

   Log, Programming,Debug     2012-11-28 11:42:23

  Do you really understand C? 21st International Obfuscated C Code Contest winning entries

The 21st International Obfuscated C Code Contest(IOCCC) officially launched the winning source code. IOCCC requires contestants to write the most creative and the most obfuscated C codes with the size limited to 4kb and less Work of each participant is impressive. The winners, including one French, one Korean, five Americans, one Belgian, one Israeli, one British, four Japanese and one Chinese. Here we list some codes: Best short program Seonghoon Kang  from Korea- Decodes spelled out ...

   C,Obsfucation contest     2012-10-25 12:26:55

  PHP to get access token for Sina Weibo app

Previously I wrote two articles about getting access token for Facebook and Twitter apps using PHP. Today I will write one more article about getting access token for Sina Weibo app using PHP. OAuth 2.0 is now the authorization mechanism of Sina Weibo API. The API authorization process is similar to the process of Twitter. It has basically two steps: 1. Authorization; 2. Get access token. 1. Create an app. I hope you know how to create an app in Sina Weibo now. If not. You can access this page ...

   PHP,access token,Sina Weibo     2013-05-16 12:07:39

  10 reasons why Dart is cooler than JavaScript

Dart is a new programming language from Google and after coding JavaScript for over one year now, I immediately felt in love with it. Coming from the Java world I had a good bunch of things I had to learn before I could use JavaScript. Some people say, you need to dig deep into JavaScript, otherwise you are not allowed to speak about the pros and cons of a language. I am not a JavaScript Ninja. But I strongly believe a programming language should be easy to learn, easy to understand and s...

   Dart,JavaScript,Comparison     2012-01-05 08:23:21

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