[iolib-devel] Re: (gcc-cpu-flags) in asdf-additions/unix-dso.lisp

[Chun Tian binghe]

"Faré" <fahree at 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 at 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?

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