On 03/18/2015 11:58 AM, Alex Blekhman wrote: > Andrew Haley <aph <at> redhat.com> writes: >> Cross-compiling from 32- to 64-bit hosts is notoriously tricky. People >> almost always go in the opposite direction. I don't even know if it >> can be done. > > I can live with 64-bit system, which has 64-bit GCC. What is essential for > me is that I can build both 32-bit and 64-bit targets and then run 32-bit > targets (during test phase of the build). > > How difficult (easy?) is it to have 64-bit Debian/Redhat machine running > 32-bit executables? Tivial. As long as you have the libraries installed it usually just works. You don't need a special GCC. Like so: zebedee:~ $ cat hello.c #include <stdio.h> int main(void) { puts("Hello, world!"); } zebedee:~ $ gcc hello.c zebedee:~ $ file a.out a.out: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.18, not stripped zebedee:~ $ ./a.out Hello, world! zebedee:~ $ gcc -m32 hello.c zebedee:~ $ file a.out a.out: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.18, not stripped zebedee:~ $ ./a.out Hello, world! Andrew.