[CMake] Problem linking to shared library (inside project) after upgrade to cmake 2.6

[Bill Hoffman]

Yogesh Marwaha wrote:
> 2008/7/13 Bill Hoffman <bill.hoffman at kitware.com>:
>> Little t usually means local linkage, so that would be why you can not see
>> the symbols from an external library.  I don't think this is a CMake issue,
>> but rather a C++ issue of some sort.  What does the header file for
>> GApplication and the .cxx file look like?
>>
> 
> There is not much in the GApplicatin header/source.
> 
> Here is the header:
> 
> #ifndef GAPPLICATION_H
> #define GAPPLICATION_H
> #include <KApplication>
> class GApplication: public KApplication{
> Q_OBJECT
> public:
>     GApplication();
>     ~GApplication();
> private slots:
>     void init();
> };
> #endif
> 
> Here is the source:
> #include "myapplication.h"
> 
> #include "gravity.h"
> #include "taglib/fileref.h"
> #include "gfiletyperesolver.h"
> #include "playlistiohandler.h"
> #include "gdevicehandler.h"
> #include <KDE/KGlobalAccel>
> #include <KDE/KMessage>
> #include <KDE/KPassivePopupMessageHandler>
> GApplication::GApplication() : KApplication( true ){
>     setApplicationName("Gravity");
>     KMessage::setMessageHandler(new KPassivePopupMessageHandler());
>     KGlobalAccel::self()->setEnabled(true);
>     TagLib::FileRef::addFileTypeResolver(new GFileTypeResolver);
>     Gravity::self();
>     Gravity::self()->systemTrayIcon();
> }
> GApplication::~GApplication(){
>     Gravity::self()->deleteSelf();
> }
> void GApplication::init(){
> }
> #include "myapplication.moc"
> 
> 
> =====================
> CMakeFiles/Gravity.dir/main.o: In function `main':
> /home/yogesh/gravity/app/main.cpp:10: undefined reference to
> `GApplication::GApplication()'
> /home/yogesh/gravity/app/main.cpp:12: undefined reference to `Gravity::self()'
> /home/yogesh/gravity/app/main.cpp:12: undefined reference to
> `Gravity::gUIInterfaceManager() const'
> /home/yogesh/gravity/app/main.cpp:13: undefined reference to
> `GApplication::~GApplication()'
> collect2: ld returned 1 exit status
> make[2]: *** [app/Gravity] Error 1
> make[1]: *** [app/CMakeFiles/Gravity.dir/all] Error 2
> make: *** [all] Error 2
> =====================
> The above linking error is shown when *app* folder is processed which
> has only one main.cpp file: -
> #include <KDE/KCmdLineArgs>
> #include <KDE/KAboutData>
> #include <QString>
> #include "gravity.h"
> #include "myapplication.h"
> int main(int argc, char **argv){
>     KAboutData aboutData("gravity", "gravity", ki18n("Gravity"),
> "0.1", ki18n("Media player"),  KAboutData::License_LGPL_V2);
>     KCmdLineArgs::init(argc, argv, &aboutData);
>     GApplication app;
>     app.disableSessionManagement();
>     Gravity::self()->gUIInterfaceManager();
>     return app.exec();
> }
> 
> ...thats why there are only four references to complaint about, and
> the make quits.
> 
> If I change CMakeLists.txt in base folder to process *modules* folder
> before *app* then there are hundreds of similar errors shown.
> 
> Just to check (not to prove anything) I created another project
> (plain/c++) using similar setup which creates a shared library and an
> executable which links to that shared library. It got
> compiled/linked/installed/executed as expected.
> 
> I can supply a copy of complete source code if someone has KDE4
> installed (for development) and wants to try it.
> 
OK, so this looks like some sort of moc issue.  Are you running moc on 
the header?  You might want to run nm on all the .o files and find out 
where the little "t" stuff is located.  Could it be that you have more 
than one file called the same thing and the headers are getting included 
wrong, or the .moc file is gettting over written?

-Bill