32 bit vs 64 bit

[lalesculiviu]

Hello!

I am interested in using the Qt with MinGW (that comes with Qt SDK 4.6.2 exe) under Windows 7 64 bit, to compile my application. I just want my program to be runnable on any Windows system, old or new. Should I take care of any compatibility issues?

If I want to produce a 64 bit program, what steps should I follow?

How do I request by command line to MinGW or Qt to produce a 32 bit version? Will 4.6.2 compile automatically for 32 bit? What about future versions of Qt?

Where can I find more information about that? I searched the Internet, but could not find too much about it.

[Archimedes]

If I remember correctly the options -m32 and -m64 will compile your program for a 32bit or a 64bit environment.
Also here http://en.wikibooks.org/wiki/Opticks...Qt_From_Source you'll find a guide on how to build Qt for 64bit.
I have never done this, so I'm just pointing to some directions.