Re: how to support 32- & 64-bit versions of libraries
"Steve M. Robbins" <steve@sumost.ca> writes:
> On Wed, Apr 01, 2009 at 05:39:33PM +0200, Goswin von Brederlow wrote:
>> "Steve M. Robbins" <steve@sumost.ca> writes:
>
>> > I've run into a roadblock, however, in that the header gmp.h is
>> > generated by configure. It has some parameters (size of a limb) that
>> > depend on whether compiled for 32 or 64 bits. So on amd64, for
>> > example, I have two incompatible gmp.h files. Matthias provided a
>> > gmp.h wrapper from Redhat that selects between architecture variants
>> > based on preprocessor symbols, e.g.
>> >
>> > #if defined(__i386__)
>> > #include "gmp-i386.h"
>> > #elif defined(__ia64__)
>> > #include "gmp-ia64.h"
>> > ...
>> >
>> > However, in the case at hand it is the same architecture. One
>> > variant is compiled with -m32 and the other with -m64. Is there a
>> > symbol that can distinguish the two so that I can use the Redhat
>> > trick? Other solutions?
>>
>> -m32 defines __i386__ while -m64 defined __x86_64__ and so on for each
>> architecture. So just use the architecture defines. The Redhat trick
>> already does the job.
>
> Hey, that's great! My next question is: how can I discover the suffix
> programmatically? Is there something like "dpkg-architecture
> -qDEB_HOST_GNU_CPU" or "gcc -dumpmachine" that will spit out the right
> suffix when given -m32 or -m64, etc?
>
> Thanks,
> -Steve
Unfortunately gcc does not care:
% gcc -m32 -dumpmachine
x86_64-linux-gnu
Best I can think is
dpkg-architecture -a<debian arch> -qDEB_HOST_GNU_CPU
MfG
Goswin
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