Re: How to find out if an architecture is 32 or 64 bit?

["T. Weyergraf" <kirk@colinet.de>]

> Hi,

Hi,

> 
> I'm lookking for my package tmview for a C solution to determine whether
> an architecture is 32 or 64 bit.
> 
> [.... code deleted ...]

> Could anyone point me to a better way to handle this?

If you need this at run-time, the ofvious way is to check, if sizeof(long) or whatever
provides the bytecount of a LP64/ILP32 programming model.

If the information is needed at compile-time, check unistd.h, were _XBS_LP64_OFF64 is
set. The relevant includes are:

bits/posix_opt.h, bits/environments.h and bits/wordsize.h

The selection, which programming model is used, is controlled there in a fairly detailed
manner, which has the advantage of being "The POSIX Way(TM)", and therefore even
portable outside the Linux world ( can anybody with access to a True64 System check this
claim ? I would be interested... )

Depending on what specific aspects of the machine's wordsize you need, you can go as
straight as checking if __WORDSIZE is set to 32 or 64, or as controlled as checking if
_XBS5_LP64_OFF64 provides a 64-bit pointer environment.

Have a look at the include-files i named above. I doubt, you'll find a situation not being
covered there ;-)
 
> Thanks in advance
> Adrian

Regards,
Thomas

-- 
Thomas Weyergraf                                                kirk@colinet.de
My Favorite IA64 Opcode-guess ( see arch/ia64/lib/memset.S )
"br.ret.spnt.few" - got back from getting beer, did not spend a lot.