[plug] Linux, Devices and Calculators

[Peter Wright]

On Sun, Nov 19, 2000 at 02:16:55PM +0800, stephen humble wrote:
> Bernard Blackham wrote:
[ snip ]
> > I have no experience with X programming, but know a fair amount of
> > C/C++, Pascal (dump the thought now), Perl and I could learn Python if
> > I had to.  I would prefer it to be portable to 'doze and ultimately
> > Macs. Qt sounds appealing...
> > 
> > Any ideas would be appreciated.
> 
> Go with the Qt version - ide expect the only problem with porting may be
> that the serial port will be handled somewhat differently between linux
> and windows
> nothing a few #ifdef LINUX and #ifdef WINDOWS cant fix though.

The only possibly major problem(s) with using Qt is that:

(a) You won't be able to port it to Macs, as there is currently no Qt for
    MacOS.

(b) If you develop using the free Qt on a Unix or Unix-like platform (eg.
    Linux), you will be required to GPL your application.

(c) If you then wish to build your GPL'ed application on Windows - you
    won't be able to, as there is no GPL or LGPL equivalent to Qt on
    Windows. The commercial version of Qt (the only version available on
    Windows) is (as far as I understand it) under a license that is not
    compatible with the GPL. 

So essentially, if you develop an app with the free Qt, you'll only be able
to use it on platforms that support the free Qt (basically all Unices with
XWindows - not MacOS and not Windows).

Alternatively, you could pay the $US2000 or so to purchase a license for
the commercial Qt/UNIX and Qt/Windows, then you can release your app under
whatever license you want - even the GPL, if you specifically write in an
exception saying "this may be linked to a non-free Qt library".


Technically, Qt is a masterpiece, extremely well documented and a joy to
work with. However, it's not perfect. :)

Pete.
-- 
http://cygnus.uwa.edu.au/~pete/

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