I am learning about shared objects (.so) / dynamic link libraries (.dll). Since I'm on Linux only .so files are relevant. Anyway, when I compile a shared library, I get multiple .so files - most of which are only links. Here is a screenshot:
Then I created another Qt console application project to test this SO. I had set up all the header files, copied every .so file from previous screenshot to this new project and added
LIBS += "libAritmeticnoKodiranjeDLL.so"
to project settings. If I compile the project it goes through OK. But when running my test app I get this error:
./DLLTester: error while loading shared libraries: libAritmeticnoKodiranjeDLL.so.1: cannot open shared object file: No such file or directory
Where is the problem and why do I get so many .so files?
Just do:
LIBS += -lAritmeticnoKodiranjeDLL
The specifics of the libraries prefix ("lib") and suffix (".so") will be taken care of by the linker.
Note how all except one are just symbolic links, and the actual file is the one with most precise version. This is to support different versions of the library, the symbolic links determine which exact version is used when version is not fully defined. If you are installing libs to system library folders, this is kind of important, but if you are just distributing one non-shared version along with your application, then you can use the name without version number.
When running application with custom libraries, you need to add the directory to LD_LIBRARY_PATH environment variable, so runtime linker finds them. See https://stackoverflow.com/search?q=LD_LIBRARY_PATH . For troubleshooting, you can run ldd yourprogram to see what shared libraries are actually loaded, and echo $LD_LIBRARY_PATH will let you make sure LD_LIBRARY_PATH is what you think it is.
I can definitely confirm from my current experience that QtCreator 4.0.3 with Qt 5.7 under Linux (Ubuntu 16.04) when building a shared library (using TEMPLATE = lib) then resulting target is libName.so (when CONFIG += unversioned_libname) or libNAME.so.1.0.0 (when CONFIG unchanged). However an application built with the very same environment links correctly against that library (LIBS += -Lfolder -lNAME) during linking but unfortunately during run-time it requests for linName.so.1 because "Application Output" says error while loading shared libraries: libNAME.so.1: cannot open shared object file: No such file or directory (I can see libName.so.1 in the generated binary of the app but NOWHERE else - not in Make files). I have spent 2 working days to figure this all out. The only way is to manually change the name of generated .so file to fit what application requests.
Related
I have made the appropriate modification as found in this thread to enable the Qt sqlite plugin to load extensions. However, when I run SELECT load_extension('spatialite_mod'), I now get the error The specified module could not be found
On a Windows Qt installation, where do I need to put the spatialite_mod.dll file so that it can be found a runtime? I have already tried putting it in the binary directory without any success.
This turned out to be a multi-part problem.
The answer to the original question is that Qt looks for the libraries in the working directory (QDir::currentPath()) and in the Windows PATH.
Part 1:
On Windows, the specified module could not be found error also can mean that one of mod_spatialite.dll dependencies was not found. In my case, I had forgotten to move these dependencies to the same directory as mod_spatialite.dll. They include:
libgcc_s_dw2-1.dll
libstdc++-6.dll
libsqlite3-0.dll
libxml2-2.dll
zlib1.dll
libfreexl-1.dll
libgeos_c-1.dll
libgeos-3-5-0.dll
libiconv-2.dll
liblzma-5.cll
libproj-9.dll
Part 2:
The libgcc_s_dw2-1.dll and libstdc++-6.dll libraries shipped with libspatialite do not work with Windows 10. Read more about this here and here. They would crash the program when loaded. The fix for me was to grab the same libraries from my Qt installation at C:\Qt\5.11.3\mingw53_32.
I downloaded Qt5.6 VS2013 32bit and try to run the official example of QtWebEngine.
I just followed the instruction but
When linking it gives out an error of
LNK1104 file not found c:\Users\qt\work\install\lib\Qt5Widgetsd.lib.
However, I have no idea of where this path c:\Users\qt\work\install\lib\ comes from.
I did text search in all directories of example folder and no hits other than generated files(makefiles and pdbs).
I also checked system environment variables but no hits.
Furthermore, I checked Qt Creator'r Projects panel and its Build Environment and still no hits.
Did I miss something?
P.S. this error was given out by linking DemoBrowser example of QtWebEngineWidgets pro
The link is generated by qmake when it generates the build scrip from the qt project file (*.pro). It is based from the qmake application path that is generaly installed together with the libraries (check you qt kit setup to change it if needed: Jst browse to qmake.exe application).
Then try regenerate the build script. It should fix the issue.
You may also have issue with installation not being in debug mode; you are trying to use Qt5Widgetsd.lib library instead of the non-debug one Qt5Widgets.lib
I am having the same issue described in this post on the py2app mailing list.
I have a python application that uses a sqlite database. On my machine, which has all the dependencies installed, there are no issues. However, when I bundle the application with py2app, clicking a menu that causes the database to be accessed results in this error:
Database error: Driver not loaded Driver not loaded
For the Windows installer, the files in \Qt\version\plugins\sqldrivers\*.* can be copied to \myApp\sqldrivers\*
The same files on the Mac can be found in　/opt/local/share/qt4/plugins/sqldrivers (installed via Macports).
However, copying the sqldrivers directory to my application's Resources or Frameworks directories still results in the same error.
How can I add sqlite support into my application that is built using py2app?
Turns out the pyside recipe does have a way to specify which qt-plugins you need...
options=dict(py2app={
'argv_emulation': True,
'qt_plugins' : "sqldrivers",
}
),
This puts all the sqldrivers into the right directory and setups qt.conf correctly.
have you tried what he said
in this post ?
py2app setup.py usage question
it mentioned
you need to include the sqlalchemy.dialects.sqlite as a package
I managed to get this to work as follows:
After building with py2app, inside the application's Contents directory, make a new plugins directory.
Then copy sqldrivers/libqsqlite.dylib into this plugins directory.
Afterwards, install_name_tool has to be used to change the library links in libqsqlite.dylib to point to the Qt libraries in the application's Frameworks directory rather than the system Qt libraries.
I'm developing a Qt application in Linux using Qt Creator (2.1 RC). I've created 2 projects, and used the wizard to add the library project to the application project. However when I run it, I receive the error:
/home/jakepetroules/silverlock/silverlock-build-desktop/desktop/silverlock: error while loading shared libraries: libsilverlocklib.so.1: cannot open shared object file: No such file or directory
Is there some qmake variable I can set so that Qt Creator will set up the environment properly to run? It's quite annoying to have to copy all the files to another directory with a launcher script just to be able to test the build. On Windows it works perfectly - Qt Creator automatically adds the directories containing the DLLs to the PATH when it runs your application (where running it from Explorer would say DLL not found). Mac OS X is even worse, having to run install_name_tool on everything...
So how can I set up my qmake files so everything works right from the run button in Qt Creator? Kind of hard to debug without this ability, too.
I've had a similar problem running qt apps with QTCreator on my linux machine. I've solved it by adding following lines to the .pro file of the client application:
unix:LIBS += -L/home/projects/my_libs/ -lmy_lib
unix:{
QMAKE_LFLAGS += -Wl,--rpath=/home/projects/my_libs/
QMAKE_LFLAGS_RPATH=
}
info on rpath is here: rpath
hope this helps, regards
Yes, Creator has a section where you can set whatever environment you need for running your app.
On Creator 2.0.0 this is accessed by: Projects -> Targets -> (your target) -> Run -> Run Environment (after you have opened your project)
You can then add or remove any environment variables you'd like, including LD_LIBRARY_PATH One thing I'm not sure of is if it is possible to substitute e.g. the build path into the value of those variables, so that you don't have to hardcode that into your LD_LIBRARY_PATH.
Another option would be to add a small shell script to your source tree which sets whatever variables are necessary, and add a "Custom executable" run configuration to run that script. That's accessed through the same screen.
Just using this:
unix:LIBS += -L/home/projects/my_libs/ -lmy_lib
unix:{
QMAKE_LFLAGS += -Wl,--rpath=/home/projects/my_libs/
}
It's sloved my problem too.
To get Facebook integration in our Nokia Symbian application we intend to use this library:
http://gitorious.org/qfacebookconnect
It is not otherwise working completely correctly, but it's a good start.
I have my project (.pro and .cpp files, using Qt Creator), which works fine in the emulator. I included this libqfacebook in the project in this way (in the .pro file):
LIBS += -LC:\projects\Pristop\Nokia\facebook_lib\libqfacebook-build-simulator\debug -lqfacebookconnect
INCLUDEPATH += C:\projects\Pristop\Nokia\facebook_lib\qfacebookconnect\inc
It works fine in the emulator. I use Qt Creator for everything, also to build libqfacebook. But if I want to test the application on a real phone, so to prepare a .sis file, I get this error:
:: error: No rule to make target `\NokiaQtSDK\Symbian\SDK\epoc32\release\armv5\LIB\qfacebookconnect.dso', needed by `\NokiaQtSDK\Symbian\SDK\epoc32\release\gcce\udeb\DogajaItak.exe'. Stop.
So I need to get a .dso file based on the source code of the qfacebookconnect library. For the emulator .lib and .pdb were enough. Obviously the difference is that .dso is arm while .lib & .pdb are x86.
If I try to configure qfacebookconnect to build for the phone, I get this error:
Makefile:232: error: PKG file does not exist, 'sis' and 'installer_sis' target are only supported for executables or projects with DEPLOYMENT statement. Stop.
It is correct that I do not want a .sis, all I want is a .dso.
If I go to Projects->Build Settings for Symbian Device for qfacebookconnect and I remove the build step "create SIS package" for qfacebookconnect, there is no error anymore, but I still don't believe it built a .dso for me.
So the question is how to configure Qt Creator or the .pro file to build me a .dso, or how to include external libraries in my .sis in another way?
I needed to freeze the library..
I found all the information there:
https://code.google.com/p/qfacebookconnect/issues/detail?id=13