On Wed, 2007-07-18 at 16:55 -0600, clemens@xxxxxxx wrote: > OK, a dumb question, but Ive always just assumed that all my machines were > 32bit, and ignored 64bit stuff. > > Now more than 1/2 are 64bit. > > So the dumb question: How do you compile in 64bit mode? > Im sure its there in the gcc man page, but after scanning the first > 20-30pages Im about to go to sleep... > > And, is there some place to put this so that gcc ALWAYS compiles > in 64bit mode? Or does so by default. > > Or does gcc look at the machine architecture and make a decision on > its own. > > So, a quick discussion of the niceties of 32/64bit compiling would be > appreciated. A 64-bit machine by default compiles 64 bit code. Conversely, a 32-bit machine compiles 32-bit stuff. You can force a 64-bit machine to build 32-bit stuff, specify "-march=i686" or similar thing. "-m32" is similar, but doesn't optimize for 686 processors (more of a "generic 32-bit" switch). So, unless you have a specific need to compile for a 32-bit environment on a 64-bit system, don't worry about it. The compiler will sort it out for you. ---------------------------------------------------------------------- - Rick Stevens, Principal Engineer rstevens@xxxxxxxxxxxx - - VitalStream, Inc. http://www.vitalstream.com - - - - Give me ambiguity or give me something else! - ----------------------------------------------------------------------
