What is the purpose of a these #define within an enum?

I found this code in the linux headers, /usr/include/dirent.h:

enum   

  {    

    DT_UNKNOWN = 0,

# define DT_UNKNOWN DT_UNKNOWN

    DT_FIFO = 1,

# define DT_FIFO    DT_FIFO   

    DT_CHR = 2,

# define DT_CHR     DT_CHR

    DT_DIR = 4,

# define DT_DIR     DT_DIR

    DT_BLK = 6,

# define DT_BLK     DT_BLK

    DT_REG = 8,

# define DT_REG     DT_REG

    DT_LNK = 10,

# define DT_LNK     DT_LNK

    DT_SOCK = 12,

# define DT_SOCK    DT_SOCK   

    DT_WHT = 14

# define DT_WHT     DT_WHT

  };

C++ versus D

Is the D language a credible alternative to Java and C++? What will it take to become a credible alternative? Should I bother learning it? Does it deserve evangelizing?

Bizarre use of conditional operator in Linux

In the 3.0.4 Linux kernel, mm/filemap.c has this line of code:

How to get 100% CPU usage from a C program

This is quite an interesting question so let me set the scene. I work at The National Museum of Computing, and we have just managed to get a Cray Y-MP EL super computer from 1992 running, and we really want to see how fast it can go!

Finding current executable"s path without /proc/self/exe

It seems to me that Linux has it easy with /proc/self/exe. But I'd like to know if there is a convenient way to find the current application's directory in C/C++ with cross-platform interfaces. I've seen some projects mucking around with argv[0], but it doesn't seem entirely reliable.

Write applications in C or C++ for Android?

I'm trying to develop/port a game to Android, but it's in C, and Android supports Java, but I'm sure there must be a way to get a C app on there, anyone knows of a good tutorial on the subject?

Why main does not return 0 here?

I was just reading

ISO/IEC 9899:201x Committee Draft — April 12, 2011

Is it safe to parse a /proc/ file?

Well, this is going to be a short one...

I want to parse /proc/net/tcp/ , but is it safe? I mean, how to open and read it and not be afraid, that some other process (or the OS) will be changing it in the same time?

Vim and Ctags tips and tricks

I have just installed Ctags (to help with C++ development) with my Vim (or rather gVim), and would like to find out your favorite commands, macros, shortcuts, tips that go along with it...

What is ":-!!' in C code?

I bumped into this strange macro code in /usr/include/linux/kernel.h :

/* Force a compilation error if condition is true, but also produce a

   result (of value 0 and type size_t), so the expression can be used

   e.g. in a structure initializer (or where-ever else comma expressions

   aren't permitted). */

#define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); }))

#define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); }))

What is the LD_PRELOAD trick?

I came across a reference to it recently on proggit and (as of now) it is not explained.

Why main does not return 0 here?

I was just reading

ISO/IEC 9899:201x Committee Draft — April 12, 2011

Very small programs to improve programming skills?

I realize that to become a better programmer, you need to program! So obviously the more practice, the better you become.

Vim and Ctags tips and tricks

I have just installed Ctags (to help with C++ development) with my Vim (or rather gVim), and would like to find out your favorite commands, macros, shortcuts, tips that go along with it...

How much to grow buffer in a StringBuilder-like C module?

In C, I'm working on a "class" that manages a byte buffer, allowing arbitrary data to be appended to the end. I'm now looking into automatic resizing as the underlying array fills up using calls to realloc . This should make sense to anyone who's ever used Java or C# StringBuilder . I understand how to go about the resizing. But does anyone have any suggestions, with rationale provided, on how much to grow the buffer with each resize?

How to get PHP standard functions in C?

How can I call PHP functions from my C application?

Example:

Objective-C: unichar vs. char

I'm a little confused between a unichar and a char. Can I treat unichar's similar to char's?

Which complements Python best: Java, C, or C++?

I am in the process of applying to a Computer Science program which requires students to have at least an intro-level exposure to either Java, C or C++. I have some experience with Python and I would prefer to continue working in Python before starting another language; however, the professor said that Python was too light, i.e. "it's just a scripting language, you need to know a more robust language".

How can i do speech recognition in C or Java or PHP?

Is there any well known established framework for C or Java or PHP to do speech recognition applications? Microphone audio input and it will recognize English words. Such as pseudo code:

What are the benefits (and drawbacks) of a weakly typed language?

I'm a big fan of PHP and it's obviously a very weakly-typed language. I realize some of the benefits include the general independence of changing variable types on the fly and such.