That's not completely true. If they have the same CPU family (meaning same instruction set architecture/binary-image), and the same executable file format (ELF, DWARF, etc.), then mostly what you really need from there is compatible library layers. That is, as long as no one is doing things like system() calls (ie. stick to QT calls, and things in the libraries you've provided for compatibility, and you're ok).

This has been done, in the past, to get things like BSD based OSes to run Linux and Solaris binaries. All it takes is: same CPU, support for the executable file format, and a set of compatible libraries. And, really, that's what WINE attempts to do (it's not an emulator, it's cross platform library linking, for the MOST part). WINE just doesn't have a full set of libraries and library definitions from which to build up that environment.

Symbian and Maemo don't have that limitation -- each team can easily talk to the other. And the QT team is in that same community. I'm willing to bet that they have more than enough opportunity to develop a full scope of library definitions for providing a complete common executable environment that can run 1 exact binary image on two OSes.

My main question would be: is it

• a Symbian library set (would run on any OMAP+ELF?+Symbian+QT system),
• a Linux library set (would run on any OMAP+ELF?+Linux+QT system),
• a Maemo library set (like the last one, but requires some Maemo specifics),
• pure QT libraries (no Symbian nor Linux/Maemo calls allowed, but would then run on any OMAP+ELF?+QT system), or
• a completely different executable environment (that wouldn't run on a straight Symbian+QT environment, nor a straight Linux/Maemo+QT environment, it would require OMAP+ELF?+QT+this-extra-library)