You may be familiar with integer overflow, but what you may not be familiar with is how gcc handles signed integer overflow.First let's look at the standard, for unsigned integer, the standard says :A computation involving unsigned operands can never overflow, because a result that cannot be represented by the resulting unsigned integer type is reduced modulo the number that is one greater than the largest value that can be represented by the resulting type.In other words, unsigned integer overflow will be wrapped so that it will be still in the range of an unsigned integer.For signed integer,...

HP has just released its first beta version of the webOS, It is said the user experience of webOS is quite impressive, so I immediately had it installed on my PC. There are two versions of Beta release,one embedded version and one Ubuntu version. I briefly share my installation experience of webOS in Linux.In the official document, it says "By 'Linux' we mean 'Ubuntu Linux'", it doesn't support server version and 64 bit version of Ubuntu. Here I use Mint 13.1. Clone source code from githubAddress : https://github.com/openwebos/build-desktopgit command :1git clone https://github.com/openwebos/b...

In our day to day work. We may have many chances working on Linux/Unix systems. There are many things we may need to do, checking logs, navigating in directories, creating file or installing software. We may use many commands to complete the work, such as ls, mkdir, cd etc.Below are my frequently used Linux commands or programs recently:pwd : print working directory, sometimes I need to check which working directory I am in in order to know where to go next.ls : List current directory files, before I can operate on a directory, I need to know what are in the directory so that I may not delete ...

Are you used to use cPanel or Plesk on VPS for your PHP website management? If for some reason you don't want to use them? What can you do? How do you maintain your website? How do you access Emails, use FTP to upload files or use phpMyAdmin to manage your databases? You may need to configure all these services yourself on a VPS without cPanel or Plesk or other similar apps.But to configure all these services on a Linux server is not an easy job. You may spend many nights but still fail to get satisfactory results. Here I share with you some useful links which can help you to configure a worki...

phpMyAdmin is a free and open source tool written in PHP intended to handle the administration of MySQL with the use of a Web browser. It can perform various tasks such as creating, modifying or deleting databases, tables, fields or rows; executing SQL statements; or managing users and permissions.Today I walk through you the steps to install phpMyAdmin on CentOS. Actually, these steps are applicable to other Linux systems as well. 1. Download the phpMyAdmin from Sourceforge.net. Run command:wget -c http://sourceforge.net/projects/phpmyadmin/files/phpMyAdmin/3.5.1/phpMyAdmin-3.5.1-english.tar....

These two days, I am building a website and deploying it on a VPS server which uses CentOS 5. I don't have cPanel or Plesk for my account, so I need to install and configure everything myself including Apache, PHP, MySQL and FTP server, also today's topic cron job. Since my website has a ranking algorithm to calculate the rankings of each link and update the ranking on database and I need to calculate the rankings every 5 minutes, so I think to use cron jobs. Here are what I have done which may help you.First we need to understand the crontab commands, it can have different options with this c...

In past few days, there are many tech news which are related to open source. For example, Microsoft enables Linux on its Windows Azure cloud, Facebook open sourced its C++ library Folly and Samsung joined Linux foundation. Now more and more big companies realize the power of open source and are willing to contribute to the open source community. It will benefit not only developers but also these big companies as well.By providing some open source libraries or projects, developer may reduce their time of development and enjoy some performance improvement from open sourced resource. Some of thes...

Have you ever looked in your / directory, you’ll see a lot of directories. Here we are presenting beginners guide to linux directory structure explaining what they mean and what are the contents of these directories.Screenshot of contents of root directory: /This is called root partition. All files and directories start with root partition. Write privileges under this directory are avaible with root user only. Not to confuse it with root user’s home directory, know the difference, “/” is root partition while root user’s home directory is “/rootâ€�...