Solved Linux Qt Creator compiling third party library problem

[mireiner]

Hi there,

I'm a Linux beginner. When compiling a project with a third party static library (.a file) with Qt Creator 4.12.4 (Qt 5.15) following errors show up:

//libswe.a(sweph.o): undefined reference to symbol 'dladdr@@GLIBC_2.2.5'
/lib/x86_64-linux-gnu/libdl.so.2: error adding symbols: DSO missing from command line
collect2: error: ld returned 1 exit status

Does anyone know what is missing and can give me some help on this?

Thanks in advance,
mireiner

[SGaist]

LIBS += -ldl

[SGaist]

Hi,

Where does that static library come from ?
How what is built ?
On which distribution ?

[mireiner]

Hello SGast,

meanwhile I tried another distro - same problem. The tested distros are:

Linux Mint 20 Cinnamon (Ubuntu based)
Manjaro 20.03 KDE (Arch Linux based)

On Intel i7 processor with integrated uhd 630 graphics.

I doubt that the problem is related to the third party library. The problem is my poor understanding how to link needed Linux libraries to my Qt project.

I took a look into a makefile that came with the third party library for testing proposes. And there is says:

swemini: swemini.o libswe.a
	$(CC) $(OP) -o swemini swemini.o -L. -lswe -lm -ldl

Because I didn't include the last two Linux libraries -lm -ldl that might be the cause of the errors. But I don't know how to do that.

Do you know these Linux libraries and how to include them into an Qt Creator project?

[SGaist]

LIBS += -ldl

[mireiner]

Yes, problem solved.
I'm a bit ashamed that it was so simple and I tried so hard and didn't get it.

Thank you very much SGaist!