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SEARCH KEYWORD -- Weak reference

  About .NET memory leak--GC,Delegate and weak reference

Memory leak is always a headache for many programmers, the situation is much better now in some languages which have GC mechanism, but still we may face some memory leak issues when we write programs. 1. What is memory leak? Memory leak is not that the memory chip is broken. In short, it's about that the memory requested is not released at the expected time as an expect way. So what is the expected time? This is very important for you to understand memory leak. If the time an object taking the m...

   .NET,GC,Reference counting,Mark and sweep,Weak reference     2013-05-25 12:59:09

  gethostbyname vs getaddrinfo

getaddrinfo is slower than ping when resolving domain names. I think ping uses gethostbyname to resolve a domain name. The question becomes whether getaddrinfo is slower than gethostbyname. After testing with both functions, we find that getaddrinfo is really slow compared to gethostbyname. By strace tracking,  we find getaddrinfo will communicate with DNS server 10 times and gethostbyname will communicate with DNS server communication twice.gethostbyname is an old way to resolve domain nam...

   C++,network,DNS     2012-08-15 14:06:34

  iPhone 5 first weekend sales over 5 million

Within 24 hours openning for pre-order, 2 million iPhone 5 have been ordered, Apple announces that  sales of iPhone 5 are over 5 million in 3 days on sale., in addition, iOS devices upgraded to iOS6 are around 100 million. Apple CEO Tim Cook says : Demand for iPhone 5 has been incredible and we are working hard to get an iPhone 5 into the hands of every customer who wants one as quickly as possible,While we have sold out of our initial supply, stores continue to receive iPhone 5 shipments ...

   iPhone5,,iOS6,sale,pre-order     2012-09-24 10:55:12

  Differences between bashrc and profile in Linux

After login to a Linux system, the command console will show up with a prompt label such as # or ~, a shell command can be typed after this prompt and the system can execute the command thereafter. All these operations are handled by shell. Shell is a command language interpreter that executes commands read from the standard input device (keyboard) or from a file. There are different types of shells such as bash, ksh, csh etc. The most commonly used of them is bash and it's also the de...

   LINUX,PROFILE,BASH,BASHRC,.BASHRC,.PROFILE     2016-11-05 22:17:51

  Strict mode in JavaScript

1. Introduction In addition to normal mode, ECMAScript 5 includes the other mode : strict mode. It means it will make JavaScript codes execute in a more strict environment. The purposes to have strict mode are: Remove some unreasonable and parts of JavaScript syntax. Reduce some of the quirk behaviors. Remove some insecure parts of code execution. Make the execution environment more secure Improve interpret efficiency and increase the execution speed Build foundation for future JavaScript versi...

   JavaScript, Strict mode. Introduction     2013-01-17 05:00:26

  System programming is still there

System programming is the practice of writing system software. System software lives at a low level, interfacing directly with the kernel and core system libraries. Your shell and your text editor, your compiler and your debugger, your core utilities and system daemons are all system software. But so are the network server, the web server, and the database. These components are entirely system software, primarily if not exclusively interfacing with the kernel and the C library. But nowadays more...

   System programming     2014-02-27 05:46:48

  CSS Rounded Corners In All Browsers (With No Images)

In the past two years, increased browser support has transformed CSS3 from a fringe activity for Safari geeks to a viable option for enterprise level websites. While cross-browser support is often too weak for CSS3 to hold up a site’s main design, front-end developers commonly look to CSS3 solutions for progressive enhancement in their sites. For instance, a developer might add a drop-shadow in Firefox, Safari and Chrome using -moz-box-shadow and -webkit-box-shadow, and the...

   CSS,Rounded corner,No image,IE,Chrome,Fi     2011-06-30 22:50:34

  How many bytes a boolean value takes in Java?

Have you ever wondered how many bytes a boolean value takes in Java? One byte, this might be the answer comes out of your mind right away. But is it? Let's dig in more. Per Oracle documentation on boolean value definition, there is below statement: boolean: The boolean data type has only two possible values: true and false. Use this data type for simple flags that track true/false conditions. This data type represents one bit of information, but its "size" isn't something that's precisely defin...

   JAVA,INTERVIEW,SIZE,BOOLEAN     2020-02-29 02:49:18

  Books for entry level C programmers

In computing, C is a general-purpose programming language initially developed by Dennis Ritchie between 1969 and 1973 at Bell Labs Its design provides constructs that map efficiently to typical machine instructions, and therefore it found lasting use in applications that had formerly been coded in assembly language, most notably system software like the Unix computer operating system.To learn C, we need to read many C books and have many practices. Here we summarize a list of C books which may h...

   C,Book,Beginning     2012-07-26 14:00:51

  /dev/null and /dev/tty in Linux

In Linux, there are two special files /dev/null and /dev/tty. /dev/null will drop all the data written to it, i.e, when program writes data to this file, it means the program has completed the data write operation. But in  fact it does nothing, if you just want the status of a command but not the output of a command, this feature will be very useful. See below shell codes:     /> vi test_dev_null.sh        #!/bin/bash    if grep...

   Linux,/dev/null,/dev/tty     2013-03-04 02:23:23

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