At Sat, 29 Oct 2011 16:19:53 +0200, Niklas Larsson wrote: > 2011/10/29 Thomas Chust <ch...@web.de>: > > 2011/10/29 Norman Gray <nor...@astro.gla.ac.uk>: > >> [...] > >> Is there a recommended way to detect whether racket is a 32- or > >> 64-bit executable? > >> [...] > > > > Hello Norman, > > > > while I don't know whether this strategy is particularly > > recommendable, I would suggest to use utilities from the FFI module: > > > > (require (only-in ffi/unsafe compiler-sizeof)) > > > > (compiler-sizeof 'long) ; => 8 on a 64-bit system > > ; => 4 on a 32-bit system > > > > That doesn't work in all cases, sizeof(long) is 4 on 64-bit Windows.
Right -- use `_pointer' or `_intptr', and that's probably the strategy I'd use. At Sat, 29 Oct 2011 09:31:17 -0500, Robby Findler wrote: > Another not so great way, in Racket, to tell if the current racket is > built as a 64 bit or 32 bit executable (is that what you're wanting?) > > ;; 64bit? : -> boolean > (define (64bit?) (eq? (expt 2 61) (expt 2 61))) This is not a good approach. If you happen to compile on a 64-bit machine, the compiler will end up constant-folding to (define (64bit?) #t) More generally, even on a 32-bit platform, I can imagine the compiler one day "intern"ing the bignums that it generates through constant folding. This variant is reliable, though: (define (64bit?) (fixnum? (expt 2 33))) The compiler doesn't constant-fold `fixnum?' (though maybe it should constant-fold when the argument is a fixnum on all platforms). _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/users
