When should -m32 option of gcc be used?

Question

I am writing a program which if I compile on a Suse 10 32-bit system without adding the -m32 option and execute it on Suse 10 64-bit, it works fine.

In

Answer 1

There is no problems in running 32 bits executables on 64 bit OS (as long as 32 bit dynamic libraries are present and found).

-m32 is there to compile 32 bits objects on a compiler configured to compile 64 bits objects by default.