Statically Link 3rd Party Library Built with CMake into Qt 5.12.11 Project Built with QMake in Qt Creator

SGaist

@Crag_Hack check whether you have the dynamic and static libraries in the same folder, if so, move the shared one somewhere else otherwise the linker will prefer them depending on how the arguments were feed.

As for QtCore and QtNetwork, that's normal. Unless you use only static libraries, you will have such dynamic dependencies.

The only way to have "no dependencies at all" is to build absolutely everything statically, including setting the VS runtime to static, which means that you will have to rebuild everything when they release a new runtime (think of security updates). This also implies additional requirements with regard to the license your dependencies are using (for example LGPL for Qt). That said, since you are already using a dynamic version of Qt, I don't really see the benefit of using a static version of SimpleMail2 beside removing one file to deploy.

Crag_Hack

@SGaist I had the dll and the lib for Simple Mail in the same directory so I renamed the dll and still have the same DLL dependency after rebuilding the program. lib files are always static right? I could try rebuilding the libraries but I'm pretty sure I did it right the first time.

Also re

including setting the VS runtime to static

you just mean build Qt static right?

Crag_Hack

@SGaist I tried rebuilding the simple mail libraries with no luck. Here are a couple screenshots of the shared lib settings:

Crag_Hack

@Crag_Hack And here's the library build directory

SGaist

A .lib file can either be an import or a static library. Seeing the size of yours, it's clearly the former.

Crag_Hack

@SGaist Thanks, any way to force build of a static library instead of import library? couldn't find anything on google...

SGaist

Clean the content of the build folder and rebuild the project ensuring that BUILD_SHARED_LIBS is set to off.

Crag_Hack

@SGaist I think I found the problem after some head smashing... in the CMakeLists.txt for the Simple Mail library it has:

add_library(SimpleMail2Qt${QT_VERSION_MAJOR} SHARED
    ${simplemailqt_SRC}
    ${simplemailqt_HEADERS}
    ${simplemailqt_HEADERS_PRIVATE}
)

The ${simplemailqt_***} variables are just lists of source files.

I changed to STATIC instead of shared but then get a bunch of inconsistent dll linkage warnings and three definition of dllimport static data member not allowed errors (see screenshot below).

Does that mean the developer designed the library to be shared only? Would it take a herculean effort to convert it to static? Thanks again!

Crag_Hack

@SGaist Got any input? A little might go a long way, thanks!

SGaist

Sorry I lost track of this thread. Can you post the exact link of the sources of that library (just to be sure we are looking at the same thing).

Crag_Hack

@SGaist
Here 'tis. I'm looking at the CMakeLists.txt in the src directory which is the location of the library code.

SGaist

I found the issue, there's a glitch in the src CMakeLists.txt, they have hard coded the library build as shared. Just removed that from the add_library line, configure the build to be static and you will have a static build of it.

Crag_Hack

@SGaist Thanks, SGaist, I found the same issue, see three posts ago. I just now tried leaving both STATIC and SHARED out of add_library and get the same compile errors/warnings as using STATIC with add_library.

I have the same question as before... Does this mean the developer designed the library to be shared only? Would it take a herculean effort to convert it to static? Thanks again!

SGaist

Do you mean you can't get a static build of the library ?

Crag_Hack

@SGaist These are the errors/warnings I get when I try to build the library without the SHARED option passed to add_library:

alt text

SGaist

With BUILD_SHARED_LIBS set to OFF ?

Crag_Hack

@SGaist Yep that's correct.

Crag_Hack

I tried add_compile_definitions(PLUGIN_LIBRARY) to both CMakeLists.txt with no luck.

Crag_Hack

@SGaist I might have just gotten it to work... will confirm tomorrow but it looks pretty convincing. I added add_compile_definitions(SimpleMail2Qt5_EXPORTS) to both CMakeLists.txt's. Forgot how I arrived at this necessity I'll try to remember tomorrrow :) Thanks for the help!

Crag_Hack

@SGaist I finally got the library to compile statically. I had to remove SHARED from add_library, set BUILD_SHARED_LIBS to off, and add add_compile_definitions(SimpleMail2Qt5_EXPORTS) to CMakeLists.txt.

In the SimpleMail project we have src/smtpexports.h with:

#if defined(SimpleMail2Qt5_EXPORTS) || defined(SimpleMail2Qt6_EXPORTS)
#define SMTP_EXPORT Q_DECL_EXPORT
#else
#define SMTP_EXPORT Q_DECL_IMPORT
#endif

The Q_DECL_EXPORT seems to be essential.

Now I get another error! Bloody hell.

Running NMake trying to build my project that uses SimpleMail I get some of these:

SimpleMail2Qt5.lib(emailaddress.cpp.obj) : error LNK2038: mismatch detected for 'RuntimeLibrary': value 'MD_DynamicRelease' doesn't match value 'MT_StaticRelease' in qtsingleapplication.obj

and a lot of these:

SimpleMail2Qt5.lib(mimemessage.cpp.obj) : error LNK2019: unresolved external symbol "__declspec(dllimport) public: __cdecl QByteArray::QByteArray(class QByteArray const &)" (__imp_??0QByteArray@@QEAA@AEBV0@@Z) referenced in function "public: __cdecl QStringBuilder<class QByteArray,class QByteArray>::operator class QByteArray(void)const " (??B?$QStringBuilder@VQByteArray@@V1@@@QEBA?AVQByteArray@@XZ)

and these:

SimpleMail2Qt5.lib(mimepart.cpp.obj) : error LNK2001: unresolved external symbol "__declspec(dllimport) public: __cdecl QByteArray::QByteArray(class QByteArray const &)" (__imp_??0QByteArray@@QEAA@AEBV0@@Z)

I'll google these guys... do you know off the top of your head what's going on?
Thanks