# Can a Ruby program determine whether it's running on a 32-bit or 64-bit system? **URL:** \ **Category:** Ruby\ **Created:** [September 3, 2008, 2:47am UTC](https://www.ruby-forum.com/t/can-a-ruby-program-determine-whether-its-running-on-a-32-bit-or-64-bit-system/147552 "2008-09-03T02:47:43Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![epasquier](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/2bfe46/32.png) [@epasquier](https://www.ruby-forum.com/u/epasquier)\ **Post date:** [September 3, 2008, 2:47am UTC](https://www.ruby-forum.com/t/can-a-ruby-program-determine-whether-its-running-on-a-32-bit-or-64-bit-system/147552/1 "2008-09-03T02:47:43Z")
I can’t go by RUBY\_PLATFORM – I’m setting up a new 32-bit Linux box, and RUBY\_PLATFORM is set to “i686-linux”. Or maybe this is a bug – repaved machine, installed Fedora Core 9, downloaded and built a vanilla Ruby 1.8.6 – but I see this on another 32-bit Linux box as well (this one’s a virtual host, but `cat /proc/ cpuinfo` suggests it’s 32-bit) If anyone’s wondering, this is related to the Komodo debugger. The ruby-debug-base component is not 32/64-bit universal, so I need to put the 32-bit binary in one dir, the 64-bit one in another, and direct the client to the right spot. Thanks, Eric P. ---
**Author:** ![epasquier](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/2bfe46/32.png) [@epasquier](https://www.ruby-forum.com/u/epasquier)\ **Post date:** [September 3, 2008, 3:03am UTC](https://www.ruby-forum.com/t/can-a-ruby-program-determine-whether-its-running-on-a-32-bit-or-64-bit-system/147552/2 "2008-09-03T03:03:30Z")
On Wednesday 03 September 2008 02:39:37 Eric P. wrote: > I can’t go by RUBY\_PLATFORM – I’m setting up a new 32-bit Linux box, > and RUBY\_PLATFORM is set to “i686-linux”. > Well, i?86 means it is 32bit. > 64-bit x86 system would have ‘x86\_64-linux’. Jan ---
**Author:** ![epasquier](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/2bfe46/32.png) [@epasquier](https://www.ruby-forum.com/u/epasquier)\ **Post date:** [September 3, 2008, 3:56am UTC](https://www.ruby-forum.com/t/can-a-ruby-program-determine-whether-its-running-on-a-32-bit-or-64-bit-system/147552/3 "2008-09-03T03:56:48Z")
Eric P. wrote: > Can a Ruby program determine whether > it’s running on a 32-bit or 64-bit system? Yes. Look at the result of calling the ‘size’ method on a Fixnum; it will be 4 on 32-bit machines, and 8 on 64-bit machines. > > 0.size > > =\> 4 ---
**Author:** ![epasquier](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/2bfe46/32.png) [@epasquier](https://www.ruby-forum.com/u/epasquier)\ **Post date:** [September 4, 2008, 12:10am UTC](https://www.ruby-forum.com/t/can-a-ruby-program-determine-whether-its-running-on-a-32-bit-or-64-bit-system/147552/4 "2008-09-04T00:10:10Z")
I got 4 on 64bit Windows Server. That doesn’t mean that it depends if it was built on 64bit or 32bit, I mean ruby core. 2008/9/2 Suraj K. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) ---
**Author:** ![epasquier](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/2bfe46/32.png) [@epasquier](https://www.ruby-forum.com/u/epasquier)\ **Post date:** [September 4, 2008, 1:50am UTC](https://www.ruby-forum.com/t/can-a-ruby-program-determine-whether-its-running-on-a-32-bit-or-64-bit-system/147552/5 "2008-09-04T01:50:45Z")
Le 3 septembre 2008 à 02:42, Eric P. a écrit : > I can’t go by RUBY\_PLATFORM – I’m setting up a new 32-bit Linux box, > and RUBY\_PLATFORM is set to “i686-linux”. Pack has a support for native size : > > RUBY\_PLATFORM > > =\> “i386-freebsd6” > > > [-1].pack(‘l!’).length > > =\> 4 While… > > RUBY\_PLATFORM > > =\> “amd64-freebsd7” > > > [-1].pack(‘l!’).length > > =\> 8 (From the Pickaxe : ‘Any of the directives “sSiIlL” may be followed by an underscore (\_) or bang (!) to use the underlying platform’s native size for the specified type’) Fred ---
**Author:** ![epasquier](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/e/2bfe46/32.png) [@epasquier](https://www.ruby-forum.com/u/epasquier)\ **Post date:** [September 4, 2008, 3:33pm UTC](https://www.ruby-forum.com/t/can-a-ruby-program-determine-whether-its-running-on-a-32-bit-or-64-bit-system/147552/6 "2008-09-04T15:33:07Z")
Suraj K. wrote: > Eric P. wrote: > > > Can a Ruby program determine whether > > it’s running on a 32-bit or 64-bit system? > > Yes. Look at the result of calling the ‘size’ method on a Fixnum; it > will be 4 on 32-bit machines, and 8 on 64-bit machines. > > > > 0.size > > > =\> 4 On my 32 bit machine I get this: p 0.size =\> 8 p [-1].pack(‘l!’).length =\> 4 I am not sure why, but there it is, fyi.