Bill Allombert on Fri, 05 Sep 2008 15:53:09 +0200


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Re: Cross compiling PARI/what about autoconf?


On Thu, Sep 04, 2008 at 12:13:08PM +0200, Jeroen Demeyer wrote:
> Karim Belabas wrote:
> 3) I noticed that a lot of checks in PARI use things like #ifdef UNIX or 
> #ifdef __GNUC__, instead of checking for the features that you want.  So 
> these things should be changed, and then you might as well use GNU 
> configure for that.

The symbol __GNUC__ is checked in _public_ headers file. This is
necessary, because once PARI is configured, build and installed
with one compiler, users might very well compile PARI programms
with _another_ compiler, and it would be wrong to assume both compilers
have the same features.

In practice it is common for users to build PARI with gcc (since it is
the default) and then build PARI programms with g++, so PARI headers
need to be compatible with both compilers even though there are subtle
differences in features.

I doubt one can write an autoconf macro that display the double
endianness (what config/get_double_format does) and support
cross-compilation.

Cheers,
Bill.

PS: Did you manage to crosscompile PARI for ppc64 ?