On 2009-06-01, Ted Walther <[email protected]> wrote: > On Mon, Jun 01, 2009 at 12:51:31PM +0000, Stuart Henderson wrote: >>On 2009-06-01, Ted Walther <[email protected]> wrote: >>> I'm preparing a port of newLISP. Is there a simple test I can run to >>> find out if the host platform is 64bit? A #define has to be set in the >>> code according to whether the platform is 64bit or not. >> >>We set _LP64 and __LP64__ variables on 64-bit arch. >> >>$ cpp -dM /dev/null | grep LP64 >>#define _LP64 1 >>#define __LP64__ 1 > > Thank you Stuart. It looks like all platforms with gcc support these > two defines. Is there any reason to prefer one or another? Google > found a netbsd post where someone said to prefer _LP64, then another > person said that is only for kernel use, use __arch64__ in userland.
I'm not sure which is preferred, but __LP64__ seems slightly more common in the wild.
