On Thu, 2006-04-06 at 10:29 +0000, Miquel van Smoorenburg wrote: > In article <[EMAIL PROTECTED]>, > Ron Johnson <[EMAIL PROTECTED]> wrote: > >On Wed, 2006-04-05 at 06:48 -0500, Mitchell Laks wrote: > >> Hi, > >> > >> I wanted to find out more about amd64, so I installed the debian distro > > > >Did you install the 64 bit version? > > > >> (etch/sid) on my amd64 dual core system. > > ^^^^^^^^ > > > >Which one? Etch or Sid? > > > >> I wanted to see if it is really 64 bit. So naively i compiled the > >> following > >> example program I found on the internet: > >> > >[snip] > >> Size of double is 8 > >> > >> So how do I see the 64 bittness of the operating system if not this way > >> with > >> gcc? I would think tha size of int would be 8? > >> uname -a > >> Linux Rashi 2.6.16.1-meshulum-2006-4-5 #1 SMP Wed Apr 5 13:34:46 EDT 2006 > >> x86_64 GNU/Linux > > > >If you did actually install the 64 bit build, do a sizeof(int *) > >and you'll see that it is 64 bits. > > > >AMD decided that, to help with compatibility with s/w written when > >sloppy programmers assumed that sizeof(int) == sizeof(*), integers > >will be 32 bits, even in 64 bit mode. > > Hmm? That's a decision of the GCC guys. They decided to make int > 32 bits. Remember it's just a C data type. > > It makes sense because this way, you have a standard C data type > for every size of integer: > > char 8 bit > short 16 bit > int 32 bit > long 64 bit
Thanks to Ray Lanza for reminding me that this is called the LP64 model, developed by DEC for the Alpha and OSF/1. http://www.unix.org/version2/whatsnew/lp64_wp.html -- ----------------------------------------------------------------- Ron Johnson, Jr. Jefferson, LA USA "He was so narrow minded he could see through a keyhole with both eyes." Molly Ivins -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
