Friday, April 17, 2009

clang compiler quickstart

Have you ever heard about clang ? It's a new compiler for C, C++ and Objective C languages. clang is being developed in a fast pace and is expected to become an alternative for the gcc compilers.

What are its advantages ? It's a compiler written from scratch, its code is completely modular and easily readable, it aims to offer user-friendly expressive diagnostics, it's much smaller and faster than gcc, it's expected to support IDE integration and code analysis and it's compatible with gcc. The C part of the compiler is in an advanced stage and can build large projects, like sqlite and the FreeBSD kernel. The C++ part is in an early stage (clang can't compile itself, for example).

Quick start:

$ svn co llvm
$ cd llvm/tools
$ svn co clang
$ cd ..
$ ./configure --prefix=/opt/clang
$ make
$ sudo make install

In the sequence above, llvm is the compiler back end and clang is the compiler front end. The compiler is installed in the /opt/clang directory, so it's available at /opt/clang/bin/clang (the directory can be deleted for a full uninstall when you're done).

Try it out:

$ cat hello.c
#include "stdio.h"

int main (void) {
printf("Hello world!\n");
return 0;
$ /opt/clang/bin/clang -o hello hello.c
$ ./hello
Hello world!
$ tar xf lame-398-2.tar.gz
$ cd lame-398-2
$ ./configure --prefix=/opt/lame CC=/opt/clang/bin/clang
$ make
$ sudo make install
$ /opt/lame/bin/lame myaudio.wav

As you can see, clang is in development stage, so it's only available trough svn.

Do you want to contribute ? See more information at clang home page !

Wednesday, April 01, 2009

POSIX 2008

The POSIX standard has been updated in December 2008. The standard is an attempt to standardize the core API of all Unix systems and, nowadays, most Unix clones try to adhere to the standard in some level of conformance (including GNU and BSD based systems). Register and read the new standard in the Open Group UNIX System site.