Link as a dll

[bmahf]

Hi all,

I am embarrassed to ask, but I cannot seem to work out how to link a project as a dll. I created a new project in Qt Creator 1.2.1, using Qt 4.5.1, and chose for it to be a C++ shared library. I just went ahead and built the library, and found that the resulting shared library had the name libMyProject.a. What I need is a .dll, rather than a .a file. How do I go about getting this. I am used to Visual Studio which would just put out a dll file.

Thanks for your help...

[bmahf]

Forgot to say that I'm using Qt on Windows Vista. I know, I should be on UNIX, but that's not always possible in this world.

Hoping that someone can help me with this probably stupid dilemma. Or was that a dilemma of stupidity.

Bruce

[axeljaeger]

Please post your .pro-file of the project. It should have something like this in it:

TEMPLATE = lib
CONFIG += shared

TEMPLATE = lib
CONFIG += shared

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If the second line is missing, it will create a static library (.a).

[bmahf]

Hey axeljaeger, thanks for the info. I didn't have the CONFIG += shared bit. Added that and it now wants to create a dll.

The new issue is that I have a hundred warnings (and some of them errors) such as:

undefined reference to `_imp___ZN10QTabWidgetC1EP7QWidget'

This is happening in 3 different cpp files, and to all of the warning/error instances have to do with Qt files, such as QString, QObject, QTabWidget, QBoxLayout, etc. Some others look like objects/variables that were defined under the covers, like FlagLocation, found in the munged string `_imp___Z13qFlagLocationPKc'. I assume that I have to add some flag to my linker command line call, but not sure what it would be.

My .pro file with your change is now as follows:

------------------MyLib.pro Start--------------------
# -------------------------------------------------
# Project created by QtCreator 2009-10-14T13:19:12
# -------------------------------------------------
TARGET = MyLib
TEMPLATE = lib
CONFIG += qt \
shared # <- added this as suggested
QT += gui \
core \
network \
xml
# DEFINES += BUILD_DLL # <- had this in there before but took it out since you didn't mention it
SOURCES += <list of sources goes here>
HEADERS += <list of headers goes here>
FORMS += src/aboutwindow.ui \
src/mylib.ui
LIBS += -L../lib \
-lidasclient \
INCLUDEPATH += ../../../idasclient/include
OTHER_FILES += src/res/MyLib.rc
RESOURCES += pictures.qrc
RC_FILE = src/res/MyLib.rc
------------------MyLib.pro End--------------------

Again, I looked around for an solution to this before reposting. Thanks again for the information you gave, and for any help you can give with this new issue...
Bruce

[bmahf]

So I should have given you this information too. The last line that was running when the compile errored out, plus a handful of the first errors tha popped up, are as follows:

g++ -enable-stdcall-fixup -Wl,-enable-auto-import -Wl,-enable-runtime-pseudo-reloc -shared -Wl,--out-implib,debug\libPaulUI.a -o debug\PaulUI.dll object_script.PaulUI.Debug -L"c:\Qt\qt-win-opensource-src-4.5.1\lib" debug\Azigo_res.o -L../lib -lidasclient -lxdi -lftk -lmsvcp80 -lmsvcr80 -lQtXmld -lQtGuid -lQtNetworkd -lgdi32 -lcomdlg32 -loleaut32 -limm32 -lwinmm -lwinspool -lmsimg32 -lQtCored -lkernel32 -luser32 -lshell32 -luuid -lole32 -ladvapi32 -lws2_32
./debug\passwords.o: In function `ZN9Passwords15initPanelWidgetEv':
C:/Users/bruce/Projects/Qt/Azigo/PaulUI/src/passwords.cpp:17: undefined reference to `_imp___ZN10QTabWidgetC1EP7QWidget'
C:/Users/bruce/Projects/Qt/Azigo/PaulUI/src/passwords.cpp:20: undefined reference to `_imp___ZN7QWidgetC1EPS_6QFlagsIN2Qt10WindowTypeEE '
C:/Users/bruce/Projects/Qt/Azigo/PaulUI/src/passwords.cpp:21: undefined reference to `_imp___ZN11QVBoxLayoutC1Ev'
C:/Users/bruce/Projects/Qt/Azigo/PaulUI/src/passwords.cpp:22: undefined reference to `_imp___ZN11QHBoxLayoutC1Ev'
C:/Users/bruce/Projects/Qt/Azigo/PaulUI/src/passwords.cpp:23: undefined reference to `_imp___ZN12QTableWidgetC1EiiP7QWidget'
C:/Users/bruce/Projects/Qt/Azigo/PaulUI/src/passwords.cpp:24: undefined reference to `_imp___ZN11QPushButtonC1ERK7QStringP7QWidget'
C:/Users/bruce/Projects/Qt/Azigo/PaulUI/src/passwords.cpp:25: undefined reference to `_imp___ZN11QPushButtonC1ERK7QStringP7QWidget'
C:/Users/bruce/Projects/Qt/Azigo/PaulUI/src/passwords.cpp:26: undefined reference to `_imp___ZN11QPushButtonC1ERK7QStringP7QWidget'
C:/Users/bruce/Projects/Qt/Azigo/PaulUI/src/passwords.cpp:29: undefined reference to `_imp___ZN7QWidgetC1EPS_6QFlagsIN2Qt10WindowTypeEE '
C:/Users/bruce/Projects/Qt/Azigo/PaulUI/src/passwords.cpp:30: undefined reference to `_imp___ZN11QVBoxLayoutC1Ev'
C:/Users/bruce/Projects/Qt/Azigo/PaulUI/src/passwords.cpp:31: undefined reference to `_imp___ZN11QHBoxLayoutC1Ev'
C:/Users/bruce/Projects/Qt/Azigo/PaulUI/src/passwords.cpp:32: undefined reference to `_imp___ZN12QTableWidgetC1EiiP7QWidget'
C:/Users/bruce/Projects/Qt/Azigo/PaulUI/src/passwords.cpp:33: undefined reference to `_imp___ZN11QPushButtonC1ERK7QStringP7QWidget'
C:/Users/bruce/Projects/Qt/Azigo/PaulUI/src/passwords.cpp:34: undefined reference to `_imp___ZN11QPushButtonC1ERK7QStringP7QWidget'
C:/Users/bruce/Projects/Qt/Azigo/PaulUI/src/passwords.cpp:37: undefined reference to `_imp___ZN7QWidgetC1EPS_6QFlagsIN2Qt10WindowTypeEE '
C:/Users/bruce/Projects/Qt/Azigo/PaulUI/src/passwords.cpp:38: undefined reference to `_imp___ZN11QVBoxLayoutC1Ev'
C:/Users/bruce/Projects/Qt/Azigo/PaulUI/src/passwords.cpp:39: undefined reference to `_imp___ZN11QHBoxLayoutC1Ev'

Hope that gives some more insight...
Bruce

[axeljaeger]

Every Qt-lib it tries to link against has a d as the last letter. This means it tries to link agains the debug-version of that library. All other libraries are not debug-libraries so I have my doubts that this will work. Anyway, are these debug-versions realy around on your system?

[bmahf]

Yes, these debug versions:

libQtCored.a
libQtGuid.a
libQtNetworkd.a
libQtXmld.a

are in the same lib directory as the non-debug versions (those with the same exact names except no d at the end).

So you are thinking that I should be linking with debug the whole way? I'm just not sure why that would be different building a dll than a straight .a library. I have built the .a library in debug mode, using the same non-debug versions of the 3 extra libraries being added in, and it built well, and I was able to call it from another driver program and run it, windows widgets and all.

Bruce

[axeljaeger]

I think you cannot mix debug and non debug libraries on windows.

[bmahf]

So I changed to a release build, cleaned the project, ran qmake to make sure, and then restarted the build, and got the same exact results. Hmmmm. Definitely stumped here...
Bruce