difference between lib and lib64 directories

[Tobias Schlüter]

Kamaraju S Kusumanchi wrote:
> After compiling gcc on a x86_64 machine, I ended up with two similar looking
> directories in the uppermost directory --- lib/ and lib64/.
> 
> What is the difference between these two directories? when should I use the
> files in lib64/ and when should I use lib/? If there is a short document
> where issues like this are explained in more detail, I appreciate if some
> one can point that to me.

gcc on x86_64 by default is multi-libbed, that means it can compile 
binaries both for 32-bit and 64-bit targets (-m32 vs -m64).  The 
directories you mentioned correspond to the libraries for these two targets.

Cheers,
- Tobi