Cross-compilation issues with GCC/G++

Question

I am using gcc to compile a C++ application on my CI server (http://ci.berboe.co.uk) and as the vps that it is compiled on has the x86-64 architecture I need to cross-compile to get the compiled program to work on x86 computers.

I have installed gcc-multilib and g++-multilib and several other packages that were suggested in other places, but I still get an error when trying to compile. It is:

/usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-linux-gnu/4.4.5/libstdc++.so when searching for -lstdc++
/usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-linux-gnu/4.4.5/libstdc++.a when searching for -lstdc++
/usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-linux-gnu/4.4.5/libstdc++.so when searching for -lstdc++
/usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-linux-gnu/4.4.5/libstdc++.a when searching for -lstdc++
/usr/bin/ld: cannot find -lstdc++
collect2: ld returned 1 exit status

Full logs are available here: http://ci.berboe.co.uk/job/MCServer%20Linux-x86/11/console

Any help towards resolving this issue would be much appreciated.

Edit:

/usr/bin/ld: i386:x86-64 architecture of input file `/usr/lib/gcc/x86_64-linux-gnu/4.4.5/../../../../lib/crt1.o' is incompatible with i386 output
/usr/bin/ld: i386:x86-64 architecture of input file `/usr/lib/gcc/x86_64-linux-gnu/4.4.5/../../../../lib/crti.o' is incompatible with i386 output
/usr/bin/ld: i386:x86-64 architecture of input file `/usr/lib/gcc/x86_64-linux-gnu/4.4.5/crtbegin.o' is incompatible with i386 output
/usr/bin/ld: i386:x86-64 architecture of input file `/usr/lib/gcc/x86_64-linux-gnu/4.4.5/crtend.o' is incompatible with i386 output
/usr/bin/ld: i386:x86-64 architecture of input file `/usr/lib/gcc/x86_64-linux-gnu/4.4.5/../../../../lib/crtn.o' is incompatible with i386 output
/usr/bin/ld: final link failed: Invalid operation

I get this after having fixed the previous problem.

Answer 1

• Install 32 bits libs (ia32-libs in some distros, moving to this: http://wiki.debian.org/Multiarch/HOWTO in others, more on that if you ask for it).
• Be sure to add the i386 library path to your LD_LIBRARY_PATH env. variable. (most certainly export LD_LIBRARY_PATH = ${LD_LIBRARY_PATH}:/lib32:/usr/lib32:/usr/lib/i386-linux-gnu and so one).
• Be sure to add the i386 include path to your LD_INCLUDE_PATH environment variable.

Feel free to look for these libraries (once installed of course), using:

find / -iname "*libstdc++.so*" 2> /dev/null

for instance for the libstdc++.so library. find should report some path that you will be able to add to your LD_LIBRARY_PATH environment variable.

Answer 2

There are two options that might work:

1. Install ia32-libs package by running sudo apt-get install ia32-libs . It is just a hunch, it might or it might not work.
2. Another solution can be to install a 32-bit linux on a virtual machine to compile the code.

This link might help: - http://en.sfml-dev.org/forums/index.php?topic=6034.0

Answer 3

You'd be better off making an i386 chroot. mk-sbuild (in ubuntu-dev-tools) and schroot make these very easy to manage.