How to compile a 32-bit binary on a 64-bit linux machine with gcc cmake

Question

Is it possible to compile a project in 32-bit with cmake and gcc on a 64-bit system  It probably is  but how do I do it   When I tried it the  ignorant  way  without setting any parameters flags etc  just setting LD LIBRARY PATH to find the linked libraries in   tools lib it seems to ignore it and only look in subdirectories named lib64

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One way is to setup a chroot environment  Debian has a number of tools for that  for example debootstrap

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In later versions of CMake  one way to do it on each target is   set target properties MyTarget PROPERTIES COMPILE FLAGS  -m32  LINK FLAGS  -m32    I don t know of a way to do it globally

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export CFLAGS -m32

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For C    you could do   export CXXFLAGS -m32   This works with cmake

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For any complex application  I suggest to use an lxc container   lxc containers are  something in the middle between a chroot on steroids and a full fledged virtual machine    For example  here s a way to build 32-bit wine using lxc on an Ubuntu Trusty system   sudo apt-get install lxc lxc-templates sudo lxc-create -t ubuntu -n my32bitbox -- --bindhome  LOGNAME -a i386 --release trusty sudo lxc-start -n my32bitbox   login as yourself sudo sh -c  sed s deb deb-src   etc apt sources list  gt  gt   etc apt sources list  sudo apt-get install devscripts sudo apt-get build-dep wine1 7 apt-get source wine1 7 cd wine1 7-  debuild -eDEB BUILD OPTIONS  parallel 8  -i -us -uc -b shutdown -h now     to exit the container   Here is the wiki page about how to build 32-bit wine on a 64-bit host using lxc

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gcc test c -o testc   file testc testc  ELF 64-bit LSB executable  x86-64  version 1  SYSV   dynamically linked  uses shared libs   for GNU Linux 2 6 9  not stripped   ldd testc      linux-vdso so 1      0x00007fff227ff000      libc so 6     lib64 libc so 6  0x000000391f000000       lib64 ld-linux-x86-64 so 2  0x000000391ec00000    gcc -m32 test c -o testc   file testc testc  ELF 32-bit LSB executable  Intel 80386  version 1  SYSV   dynamically linked  uses shared libs   for GNU Linux 2 6 9  not stripped   ldd testc     linux-gate so 1      0x009aa000      libc so 6     lib libc so 6  0x00780000       lib ld-linux so 2  0x0075b000    In short  use the -m32 flag to compile a 32-bit binary   Also  make sure that you have the 32-bit versions of all required libraries installed  in my case all I needed on Fedora was glibc-devel i386

[linux] How to compile a 32-bit binary on a 64-bit linux machine with gcc/cmake

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