size of machine 64 or 32 bit

Question

If I am working on a Unix machine, how could I know the size of the machine whether it is 64-bit or 32-bit machine?

Check the size of pointers if available in you language. Be more specific. — Guillaume, Apr 08 '10 at 16:15

score 17 · Accepted Answer · answered Apr 08 '10 at 16:42

17

AIX you can do this:

getconf KERNEL_BITMODE

HP-UX you can do this:

getconf KERNEL_BITS

or just:

getconf -a | grep KERN

Sun Solaris you can do this:

isainfo -v

For Linux, yes, the uname -a should do the trick

answered Apr 08 '10 at 16:42

BrianH

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as i am working on hp...getconf -a is not working... but getconf KERNEL_BITS is working fine. – Vijay Apr 14 '10 at 04:33
android ? :D ... i manage to install LinuxOnAndroid (rooted device) and getconf -a | grep KERN returns nothing :( also uname -m, or arch returns armv71 – THESorcerer Feb 06 '15 at 08:56
These commands only show the installed kernel bit size mode. For possible CPU modes, look in `lscpu` or at [another question's answer](https://stackoverflow.com/a/246014). – Dominik Oct 22 '17 at 13:36

score 7 · Answer 2 · edited Mar 04 '17 at 00:33

7

You can type

uname -m

if i686 or i386 is appearing, you are working with 32 bit if X86_64 is appearing, you are working with 64 bit

edited Mar 04 '17 at 00:33

Harald Nordgren

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answered Aug 22 '13 at 17:54

Poyraz

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score 6 · Answer 3 · answered Apr 08 '10 at 16:21

I have to deal with a lot of Unix platforms and generally the best way I have found is to look at the output of "uname -a". For example, if you see something like "i686 i686 i386 GNU/Linux" in the output you know it's a 32 bit machine. If "amd64" shows up it's a 64. Sometimes it's a matter of trying to run a 64 bit programme. Sometimes it's RTFM.

score 2 · Answer 4 · answered Apr 08 '10 at 16:19

2

If you're just looking to check the architecture of a machine you're on,

  %> uname -a

from the command line usually contains an indication in the output.

answered Apr 08 '10 at 16:19

Adam Holmberg

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score 1 · Answer 5 · answered Apr 08 '10 at 18:33

1

You can also try sizeof(int *). Should be 4 on 32 bit machines and 8 on 64 bit machines.

answered Apr 08 '10 at 18:33

JayM

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There's no reason why I can't target a 32-bit executable on a 64-bit computer. Where I work, we haven't bothered changing some apps to 64 bits (although some eat memory by the gigabyte, and need to be run on 64-bit machines). – David Thornley Apr 08 '10 at 19:03

Nikolai Fetissov · Answer 6 · 2010-04-08T16:21:58.853

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Assuming you want to do this at compile time - take a look here for architecture macros you can test. You are probably looking for __x86_64__.

edited Apr 08 '10 at 16:21

answered Apr 08 '10 at 16:16

Nikolai Fetissov

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size of machine 64 or 32 bit

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