On Apr 22, 2008, at 12:15 PM, Robert Terwilliger wrote: > Dear R-Mac people, > > If I build R (2.7.0) from source on a 64-bit Mac, will it be a 64- > bit app? I don't care about the GUI......... > If you use 64-bit compilers, yes. (FWIW the GUI in 2.7.0 compiles in 64-bit, too). Cheers, Simon