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?

Answer 1

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.

Answer 2

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

Answer 3

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

Answer 4

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__.

Answer 5

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

Answer 6

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.