Can you specify the path to exe in qmake? - qt

Question

Let's talk about it in linux terms. I have a ".so" file. I want to make the executable dependent on it, look for it in the same directory. How do you do it through qmake? Or can this only be achieved through the use of QLibrary?
For example, when you have a ".so" file and want to use it in your project, in qmake you write:
LIBS += -L"path to the folder that contains your .so" -lSoName
But the path is hardcoded, as you can see, and I'm wondering what to write there to make the executable look for the ".so" in the same directory.

Answer 1

You use RPATH
You can configure your binary or library to find shared library (or dll) in current directory using RPATH directive that is emedded in the binary itself which the loader respects at runtime
1- Add the following in your .pro file
unix {
message("Adding RPATH to the app")
QMAKE_LFLAGS += -Wl,-rpath=\'\$$ORIGIN/\'
QMAKE_RPATH =
}
This will set RPATH of executable to current directory and your executable will first try to look for that .so in your current directory and then in standard directory (this process is explained here)
2- After you compile and create binary VERIFY that RPATH is set correctly
objdump -x <path/to/binary> |grep RPATH
it should say $ORIGIN
Compile time configuration:
CXXFLAGS += -L"/path/to/libmarylin.so/file" -lmarylin

Answer 2

There are a few ways to do it.
If the executable is going in the current directory, just do LIBS += -L$$(PWD) -lSoName.
If you're putting the executable into some other sub-directory, specified by some qmake variable like DESTDIR, use LIBS += -L$$(DESTDIR) (or whatever variable holds that directory).
Alternatively, you can add the directory with the executable to the runtime path of the executable, which gives the dynamic linker a list of directories to search for any unresolved libraries at runtime. This can be done with QMAKE_RPATHDIR += -L$$(PWD) and LIBS += -lSoName, which will tell the linker to look for unresolved libraries in the current directory where qmake is run.
Some operating systems may also include the current directory in the runtime search path for libraries by default, in which case just doing LIBS += -lSoName should be sufficient. That is platform-dependent, though, while the above solutions are not.