[Development] Platform / compiler support

[jan-arve.saether at nokia.com]

Abecasis Joao (Nokia-MP-Qt/Oslo) wrote on 2011-11-07:

> Hi,
> 
> Time and again there is some (not-so-recent) language or compiler
> feature (e.g. C99 variadic macros, TR1, <vector>, ...) that someone
> would like to use in Qt. We usually go it the safe way out: either the
> feature is used inside feature-specific #ifdefs or its use is ditched
> altogether and we work around the lack of it.
> 
> One unfortunate aspect of staying in the safe path is that to be able
> to make the most of a given feature the onus is on the developer to
> prove the Universe is ready for it. All would be better with a clearly
> defined Universe, which we're currently missing :-)
> 
> So, that brings us to the purpose of this thread. I'd like us to
> narrow the definition of said "Universe" by specifying the compilers
> we intend to support. The list of supported compilers ties in closely
> with the platforms so we'll keep them together in this discussion.
> Nailing these down should more easily allow us to decide whether it is
> feasible to use any given compiler or language feature in Qt.
> 
> To bootstrap the discussion I started a wiki page  with a short list
> of suggested supported compilers and platforms for Qt 5:
> 
>     http://wiki.qt-project.org/Supported_Platforms
> At the bare minimum, I think we should strive to support these compilers:
> 
>     - GCC 4.2 and up
>     - MSVC 2008 and later
>     - Clang (trunk)
> On the page above I also put in a list of platforms, splitting them
> between Desktop, Embedded and Mobile. The latter two categories only
> have a placeholder row, while for Desktop I put in the following
> platform-compiler mappings:
> 
>     - Linux: gcc 4.4 (Debian stable)
>     - Microsoft Windows 7: MSVC 2008
>     - Mac OS X Lion: gcc 4.2, clang 2.9
> It'd be nice to have a list of reference platforms and even better if
> such platforms had maintainers who'd provide testing results, help fix
> issues and generally ensure the platforms are in a working state.
> Supporting a platform may also have implications on the release process.
> Anyway, all of that is a bigger discussion.
> 
> For the time being, I'm interested in the most basic level of support:
> ensuring the code compiles, keeping language and compiler feature
> #ifdef's at a maintainable (minimum) level, while still allowing
> developers to make the most of the language, compilers and standard
> libraries.
> 
> Comments?
> 
Don't we need to agree on what criteria a platform needs to fulfill in 
order to be supported? The supported platforms will change as times go by,
so the list will need to be updated by some criteria (it might cause discussion when some platforms are removed from the list, or if some
are favored above others)

 * Is the criteria the number of installed platform SDKs?
 * Is the criteria availability of platform SDK for people in the community? (e.g. MinGW has wider availability than MSVC)
 * Is the criteria that it should be used for automatic compile tests?

For instance, I'm not sure if Qt will have significant increased adoption because ICC is a supported platform, (it would be nice with some numbers, maybe a poll would suffice? :-)

cheers,
Jan-Arve Sæther