-m32 option doesn't work with gcc but works with g++

Question

I was trying to compile an application for 32 bit target on x86_64 ubuntu 12.04 machine. I installed the required packages using

sudo apt-get install gcc-multilib g++-multilib libc6-i386 libc6-dev-i386

The first command works generating the 32 bit version. However, the second command errors out

1. g++ -m32 hello.c 

2. gcc -m32 hello.c
skipping incompatible /usr/lib/gcc/x86_64-linux-gnu/4.8/libgcc.a when searching for -lgcc
/usr/bin/ld: cannot find -lgcc
/usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-linux-gnu/4.8/libgcc_s.so when searching for -lgcc_s
/usr/bin/ld: cannot find -lgcc_s

Could anyone explain to me why gcc fails to work. Am I missing some libraries?

Thanks!

Related: [Force gcc to compile 32 bit programs on 64 bit platform](https://stackoverflow.com/q/3501878) is the canonical Q&A about needing `gcc-multilib` for stuff to work. This Q&A seems to be about version mismatches. — Peter Cordes, Jun 12 '22 at 22:08

score 9 · Accepted Answer · answered Jan 21 '14 at 05:16

9

I upgraded my g++ to 4.8 and g++ -m32 stopped working too. Installing g++-4.8-multilib made -m32 option work with both gcc and g++.

answered Jan 21 '14 at 05:16

SArora

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72DFBF5B A0DF5BE9 · Answer 2 · 2014-01-21T04:31:43.013

3

I think you need this package of Ubuntu:

sudo apt-get install ia32-libs

Also confirm that you are using gcc multilib with gcc -v. If not set path accordingly or re-install gcc-multilib.

edited Jan 21 '14 at 04:31

answered Jan 14 '14 at 00:42

72DFBF5B A0DF5BE9

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I do have it installed. Apologies for not mentioning it before. – SArora Jan 14 '14 at 00:50
1

@SArora, can you try: gcc -m32 -L/usr/lib32 -o hello hello.c – 72DFBF5B A0DF5BE9 Jan 14 '14 at 00:57
Yeah. I tried that before. It doesn't work. I do have crt1.o and libgcc_s.so.1 in /usr/lib32. I wonder if it looking for something else. – SArora Jan 14 '14 at 18:24
I think you have $PATH issue, you are not using gcc multilib, can you verify gcc -v? Set path accordingly to gcc multilib binary. – 72DFBF5B A0DF5BE9 Jan 14 '14 at 20:16
Installing g++-4.8-multilib helped me resolve the issue. Thanks! – SArora Jan 21 '14 at 04:22
@SArora, great! You can choose answer if it worked for you, so question will be closed. – 72DFBF5B A0DF5BE9 Jan 21 '14 at 04:30
At the time perhaps a good answer, but in 2017 this answer is seriously outdated. – Carlo Wood Feb 09 '17 at 15:04

-m32 option doesn't work with gcc but works with g++

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