[Qt-interest] static linking

[Oliver Demetz]

Hi,

I'm not a 100% sure about that, but
as fas as I know you have to compile
the qt library with special settings
if you want to link your program
statically against it.

I would also be interested in details
on that.

Best regards,
Oliver

Linda Maria schrieb:
> 
>     Linda Maria wrote:
>      > Hi all
>      >
>      > I want to statically link my own libs, however, still dynamically
>      > linking against Qt. When I do this I get undefined reference error.
>      > Well, it is clear that the compiler is not finding my lib/somename/.a
>      > file, however, if I compile my library dynamically the compiler
>     has no
>      > problem finding /somename/.dll file.
>      >
>      > -I am working with QT 4.5
>      > -I am working on Windows with Qt Creator
>      >
>      > Example .pro files are as folow:
>      >
>      > lib pro file:
>      > QT -= gui
>      >
>      > TARGET = hello_world_lib
>      >
>      > TEMPLATE = lib
>      >
>      > CONFIG += staticlib
>      >
>      > DEFINES += HELLO_WORLD_LIB_LIBRARY
>      >
>      > SOURCES += helloworld.cpp
>      >
>      > HEADERS += helloworld.h\
>      >
>      > hello_world_lib_global.h
>      >
>      >
>      >
>      > app pro file:
>      >
>      > TARGET = hello_world
>      >
>      > TEMPLATE = app
>      >
>      > INCLUDEPATH += ..\hello_world_lib
>      >
>      > CONFIG += static
>      >
>      > LIBS += -L..\hello_world_lib\debug -lhello_world_lib
>      >
>      > TARGETDEPS += ..\hello_world_lib\debug\libhello_world_lib.a
>      >
>      > SOURCES += main.cpp \
>      >
>      > mainwindow.cpp \
>      >
>      > helloworlddialog.cpp
>      >
>      > HEADERS += mainwindow.h \
>      >
>      > helloworlddialog.h
>      >
>      > FORMS += mainwindow.ui \
>      >
>      > helloworlddialog.ui \
>      >
>      > helloworlddialog.ui
>      >
>      >
>      >
>      > ld output is:
>      >
>      > debug/mainwindow.o(.text+0x1bd): In function
>      > `ZN10HelloWorld10MainWindowC2EP7QWidget':
>      >
>      > C:/Documents and Settings/es030699/My
>      > Documents/Qt/hello_world/mainwindow.cpp:15: undefined reference to
>      > `_imp___ZN13HelloWorldLib10HelloWorld10getMessageEv'
>      >
>      > debug/mainwindow.o(.text+0x3cb): In function
>      > `ZN10HelloWorld10MainWindowC1EP7QWidget':
>      >
>      > C:/Documents and Settings/es030699/My
>      > Documents/Qt/hello_world/mainwindow.cpp:15: undefined reference to
>      > `_imp___ZN13HelloWorldLib10HelloWorld10getMessageEv'
>      >
>      > collect2: ld returned 1 exit status
>      >
>      > mingw32-make.exe[1]: *** [debug\hello_world.exe] Error 1
>      >
>      > C:\MinGW\bin\mingw32-make.exe: *** [debug] Error 2
>      >
>      > Exited with code 2.
>      >
>      > Error while building project hello_world
>      >
>      > When executing build step 'Make'
>      >
>      >
>      >
>      > Notice the line
>      >
>      > CONFIG += staticlib
>      >
>      > in the lib pro file tellst the compiler to create
>     libhello_world_lib.a
>      > to statically link agains, and not to create hello_world_lib.dll. I
>      > thought the compiler should automatically find out that only a static
>      > library is provided and link against it.
>      >
>      >
>      >
>      > Can someone please help me with this?
>      >
>      > Thanks,
>      >
>      > Linda Maria
>      >
> 
>     I do what you are trying to do routinely on both Windows and Linux.
>     However, in my library .pro files, I have
>     CONFIG += static
>     not staticlib.
>     You might look at the Makefiles that are generated by qmake and see what
>     they look like.
> 
> 
> Hi and thanks for the reply
>  
> I am still having problem with static linking. In the moment I am using 
> dynamic linking (not what I want). The output from the compiler is as 
> follow and the makefile is attached.
>  
> Please you guys that are experts on Qt, give me a hand on this.
> Thanks,
> Linda Maria
>  
> Running build steps for project hello_world...
> 
> Starting: C:/Qt/4.5.1/bin/qmake.exe C:/Documents and 
> Settings/es030699/My Documents/Qt/hello_world/hello_world.pro 
> <http://hello_world.pro> -spec win32-g++ -r
> 
> Exited with code 0.
> 
> Starting: C:/MinGW/bin/mingw32-make.exe -w
> 
> C:\MinGW\bin\mingw32-make.exe: Entering directory `C:/Documents and 
> Settings/es030699/My Documents/Qt/hello_world'
> 
> C:/MinGW/bin/mingw32-make.exe -f Makefile.Debug
> 
> Makefile.Debug:126: warning: overriding commands for target 
> `ui_helloworlddialog.h'
> 
> Makefile.Debug:123: warning: ignoring old commands for target 
> `ui_helloworlddialog.h'
> 
> mingw32-make.exe[1]: Entering directory `C:/Documents and 
> Settings/es030699/My Documents/Qt/hello_world'
> 
> g++ -enable-stdcall-fixup -Wl,-enable-auto-import 
> -Wl,-enable-runtime-pseudo-reloc -mthreads -Wl -Wl,-subsystem,windows -o 
> debug\hello_world.exe debug/main.o debug/mainwindow.o 
> debug/helloworlddialog.o debug/moc_mainwindow.o 
> debug/moc_helloworlddialog.o -L"c:\Qt\4.5.1\lib" -lmingw32 -lqtmaind 
> -L..\hello_world_lib\debug -lhello_world_lib -lQtGuid4 -lQtCored4
> 
> mingw32-make.exe[1]: Leaving directory `C:/Documents and 
> Settings/es030699/My Documents/Qt/hello_world'
> 
> C:\MinGW\bin\mingw32-make.exe: Leaving directory `C:/Documents and 
> Settings/es030699/My Documents/Qt/hello_world'
> 
> debug/mainwindow.o(.text+0x1bd): In function 
> `ZN10HelloWorld10MainWindowC2EP7QWidget':
> 
> C:/Documents and Settings/es030699/My 
> Documents/Qt/hello_world/mainwindow.cpp:15: undefined reference to 
> `_imp___ZN13HelloWorldLib10HelloWorld10getMessageEv'
> 
> debug/mainwindow.o(.text+0x3cb): In function 
> `ZN10HelloWorld10MainWindowC1EP7QWidget':
> 
> C:/Documents and Settings/es030699/My 
> Documents/Qt/hello_world/mainwindow.cpp:15: undefined reference to 
> `_imp___ZN13HelloWorldLib10HelloWorld10getMessageEv'
> 
> collect2: ld returned 1 exit status
> 
> mingw32-make.exe[1]: *** [debug\hello_world.exe] Error 1
> 
> C:\MinGW\bin\mingw32-make.exe: *** [debug] Error 2
> 
> Exited with code 2.
> 
> Error while building project hello_world
> 
> When executing build step 'Make'
> 
>  
> 
>  
> 
>  
> 
> 
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