How build 32bit on 64bit?

[noori]

Hi,
I want to create 32 bit executable of my code on 64 bit fedora.
I know how to build 32 bit rpm with mock, but for non-rpm src I dont know?
The other solution is chroot, but I dont know how setup 32bit chroot on my 64bit system.

Could you help me?
Thanks.

[ocratato]

I cannot confirm that this will work as I have no need for the additional libraries, but this page describes an approach:
http://www.cyberciti.biz/tips/compil...bit-linux.html

[noori]

Hi ocratato,
for gcc -m32 i must install required libs one by one.

[Flounder]

Unfortunately I don't think you are going to be able to make 32 bit binaries without 32 bit libraries.

[Ahmad Samir]

A couple of possibilities:
- Create a 32bit VM in libvirt (using virt-manager is not too complicated after you get used to it) and build there

- Use mock, I tested for a 32bit F20:

mock -r fedora-20-i386 --init
mock -r fedora-20-i386 --shell

the second command drops me into a 32bit chroot. The filesystem of the chroot is located under /var/lib/mock/fedora-20-i386/root/ ;I think you could switch to the mockbuild user 'su mockbuild', put your source tarball under /var/lib/mock/fedora-20-i386/root/builddir/ and build from source.

Make sure to copy/backup the files in /var/lib/mock/fedora-20-i386/root/builddir/ after finishing and before exiting from the chroot (I think mock will probably overwrite /var/lib/mock/fedora-20-i386/root if you initialize the chroot again). Alternatively you can 'mount --bind' the directory where you unpacked the source tarball of the software you want to compile under e.g. /var/lib/mock/fedora-20-i386/root/builddir/unpacked_dir and be sure to unmount it before you exit the chroot.

You can of course copy the chroot /var/lib/mock/fedora-20-i386/root/ and create a custom script to 'mount --bind' the necessary filesystems (e.g. /proc, /sys... etc) and then chroot, but if you've no problem with letting mock manage all these extra steps for you...

[noori]

Thanks Ahmad Samir