From: Guillaume Marcais <guslist@...>
Date: 2005-12-07T09:04:46+09:00
Subject: Re: Determining endianness in extconf.rb

On Wed, 2005-12-07 at 07:22 +0900, Aaron Patterson wrote:
> On Tue, Dec 06, 2005 at 02:00:33PM +0900, nobuyoshi nakada wrote:
> [snip]
> > 
> > Since config.h defines WORDS_BIGENDIAN for big-endian
> > platforms, you don't have to test it in extconf.rb.
> > 
> > -- 
> > Nobu Nakada
> 
> I guess I don't understand how I am supposed to set up my build
> environment....  As far as I can tell, config.h is generated while
> building Ruby from source.  The only config.h on my system is:
> 
> /usr/lib/ruby/1.8/i386-linux/config.h
> 
> Which does not have WORDS_BIGENDIAN listed in it.  I did find
> WORDS_BIGENDIAN in /usr/lib/ruby/1.8/i386-linux/defines.h but it just
> says to look at __BIG_ENDIAN__.

That's because you are on Intel, which is little endian.

> Can you point me to a small project that I can model my build after, or
> an example exconf.rb?

What he is saying is that you should not modify your extconf.rb file. In
your C code, just do:

#ifdef WORDS_BIGENDIAN
  // Big endian code
#else
  // Little endian code
#endif

Guillaume.

> 
> Thanks for the help!
> 
> --Aaron
> 
>