"Faré" <fahree@gmail.com> writes: OK, but why not use (cffi:foreign-type-size :pointer) instead of (cffi:foreign-type-size :int) to determine 32/64 bit OS? I think (cffi:foreign-type-size :pointer) can always do the right thing than (cffi:foreign-type-size :int)

Wrong wrong wrong!

The -m32 or -m64 are both needed, because you may be running on a machine where the default distribution is of one type, but your Lisp process is of a different size!

Here at ITA, we casually compile 32-bit Lisp executable on 64-bit machines, and the reverse is not unconceivable either.

[ François-René ÐVB Rideau | Reflection&Cybernethics | http://fare.tunes.org ] When everything seems to be going against you, remember that the airplane takes off against the wind, not with it. -- Henry Ford

On 06/06/07, Chun Tian <binghe.lisp@gmail.com> wrote:

...

Hi, iolib developers

I'm not sure why need a (gcc-cpu-flags) function to detect a gcc compile flag (-m32/-m64) and use this to compile C files.

First, use (cffi:foreign-type-size :int) to guess is wrong at least on

amd64 Linux: (cffi:foreign-type-size :int) return 4 on amd64 Linux, so you guess wrong to 32-bit.

Second, if you guess wrong, a 64-bit Lisp process will can not load a 32-bit library.

If I disable this (gcc-cpu-flags), gcc with no -m32/-m64 can always do

the right thing on both 32 and 64-bit platform, and the Lisp process can load this library. (I'm just doing this on Debian GNU/Linux amd64 and LispWorks 5.0.2 Enterprise Edition for AMD64 Linux.) Am I right?

--