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  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...

7,107 0 0          C++ NETWORK DNS

  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...

6,497 0 1          C BOOK BEGINNING

  C Macro Tips and Tricks

Preprocessor vs Compiler To properly understand C macros, you must understand how a C program is compiled. In particular, you must understand the different things that happen in the preprocessor and in the compiler. The preprocessor runs first, as the name implies. It performs some simple textual manipulations, such as: Stripping comments. Resolving #include directives and replacing them with the contents of the included file. Evaluating #if and #ifdef directives. Evaluating #defin...


  Error handling style in C

Following are three error handling styles in C.Which one you like the most? Or you don't like any one?1. /* Problem : Not enough. Easy to be wrong */int foo(int bar){        int return_value = 0;        int doing_okay = 1;        doing_okay = do_something( bar );        if (doing_okay)        { ...


  The most stupid C bug ever

I have been programming for a number of years already. I have seen others introduce bugs, and I have also introduced (and solved!) many bugs while coding. Off-by-one, buffer-overflow, treating pointers as pointees, different behaviors or the same function (this is specially true for cross-platform applications), race conditions, deadlocks, threading issues. I think I have seen quite a few of the typical issues. Yet recently I lost a lot of time to what I would call the most stupid C bug in ...

1,572 0 0          C BUG COMMENT BACK SLASH

  TIOBE : C overtakes Java as the No.1 programming language

TIOBE has released the Programming Community Index for April 2012. The highlight of this month is that C overtakes Java as the No.1 programming language again. C language is liked by more and more developers of all ages. Due to the growing popularity of the Android platform, Java decline will not be obvious. Previously Java took a very long time to overtake C, now C once again returns to the throne. The battle between these two languages will continue.The top three are respectively, C, Jav...

144,510 4 1          JAVA C.TIOBE

  Faster than C

Judging the performance of programming languages, usually C is called the leader, though Fortran is often faster. New programming languages commonly use C as their reference and they are really proud to be only so much slower than C. Few language designer try to beat C. What does it take for a language to be faster than C? Better Aliasing Information Aliasing describes the fact that two references might point to the same memory location. For example, consider the canonical memory copy: void...


  Function Pointers in C are Underrated

The function pointer in C is, in my opinion, one of the most ignored gems of the language. It’s the kind of feature you rarely need, and then suddenly, one day, you find yourself in dire need of it, as evidenced by the real-life use-case below. If you don’t know what a function pointer is in the first place, here’s the meat of it: it gives you the ability to pass a function around like a normal variable. If you know Python / Ruby / Lisp, you might know it by the name ‘lambda’, ...

2,721 0 0          C ANALYSIS POINTER