[maemo-developers] QtCreator, libraries, and multiple platforms

[From: Ville M. Vainio]

So I guessed correctly; your rationale for using a library is wrong
;-). You are introducing a bunch of deployment headaches for the sake
of having a "reusable unit", which is not in fact reused by other
applications. In general, libraries should only be introduced when
your module is part of the operating system, there are licensing
issues, or you are releasing something linked against by other
applications as well.

You should just link all the code statically with your main
application to keep things simple.

On Fri, Aug 5, 2011 at 11:39 PM, David Talmage <talmage at acm.org> wrote:
> Thanks to Danil, Ville, and Christian for taking the time to answer my call
> for help.
>
> On Thursday, August 04, 2011 06:16:16 AM Daniil Ivanov wrote:
>
>>  I agree that three project files are the way to go:
>> ...
>>  This is how you declare your library for your application
>>  http://doc.qt.nokia.com/latest/qmake-project-files.html#declaring-other-li
>> braries
>
> I got about that far.  More below.
>
> To answer Ville's question about the need for a separate library: I refactored
> my application into a library that other applications can use and an
> application that uses the library.  I have at least one more application in
> mind that will use this library.  For the curious, it's a home-grown dialog
> for choosing contacts.  I wrote it last year because the native Maemo contacts
> dialog didn't support pre-selecting some contacts. (The documentation said it
> did but I couldn't make it work at all.)
>
> To answer Christian's question about linking: By "can't link" I mean that the
> linker can't find my library, so it complains about undefined symbols.
>
>
> I have a directory structure like this:
>
> N900/app
> N900/app-uberproject
> N900/lib
>
> The contain, respectively, the app, the subdirs project, and the library.
>
> I'm building for Maemo, Harmattan, Simulator, and Remote Compiler. In short,
> everything but Desktop.
>
> When I build for Simulator, I get directories
>
> N900/app-build-simulator
> N900/app-uberproject-build-simulator
> N900/lib-build-simulator
>
> The next challenge is to teach app.pro how to find the library for the build
> platform, simulator in the example above.  It looks like some hackery-pokery
> with replace() will do the job.  I was hoping that QMake would Do The Right
> Thing for me.
>
> After that, my challenge is to install liblib.so in the simulator so that app
> can load it.  That's just the usual packaging task, right?
>
>
> Dave
>
>> On Thu, Aug 4, 2011 at 12:48 PM, Ville M. Vainio <vivainio at gmail.com> wrote:
>> > Do you have a particular reason for the requirement (like license) to
>> > have a separate library, instead of just having one monolithic
>> > application?
>> >
>> > On Wed, Aug 3, 2011 at 10:03 PM, David Talmage <talmage at acm.org> wrote:
>> >> I need help making QtCreator build an application and a library for
>> >> Maemo, Symbian (using the remote compiler), and the simulator.  I've
>> >> been all over the documentation, the forum on Qt Developer Network, and
>> >> Google.  I can't find an example that does what I need.
>> >>
>> >> I have a library (lib) and an application (app). Each one is a QtCreator
>> >> project.  I can build them individually but I can't link app with
>> >> liblib.so. Whatever I use has to work with maemo.org's autobuilder and
>> >> Nokia's remote compiler for Symbian.
>> >>
>> >> As a first pass, it would help if there is an environment variable I can
>> >> reference in app.pro like $$OUT_PWD that contains the name of the build
>> >> directory for lib.  Then linking might work.  I can hack something
>> >> together with qmake's replace(), like replace($$OUT_PWD, app, lib) and
>> >> that might work as long as app/ and lib/ were in the same directory.  I
>> >> don't know how well it would port or whether it would continue to work
>> >> when I install app and liblib.so on the phones.
>> >>
>> >> Dave
>> >> ...
>> > ...
>> ...
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