CODEWITHSUNDEEP
qtopenssl
JonasVautherin
JonasVautherin

Reputation: 8033

How do I know if Qt links against openssl, and which one?

Looking at the libs (:/Qt/5.11.0/5.11.0/gcc_64/lib/) of Qt5.11.0, I was wondering which one was linking openssl. So I ran the following:

for lib in `ls *.so`; do ldd $lib | grep ssl; done

And I got no output, suggesting that none of the libraries are linking against openssl. But I believe that Qt must link against it somehow (e.g. for networking).

How is the linking done? And where does it look for openssl? Do I have a way to know which one Qt found on my system (e.g. given I have multiple ones)?

Upvotes: 2

Views: 799

Answers (1)

JonasVautherin
JonasVautherin

Reputation: 8033

Qt links some libraries dynamically at runtime. In order to see which libraries are loaded, one can check the diagnostic output of the dynamic linker, as hinted by Matteo:

Say my executable is called QGroundcontrol:

On Linux:

LD_DEBUG=libs ./QGroundcontrol 2>&1 | grep -E "ssl|crypto"

On macOS:

DYLD_PRINT_LIBRARIES=1 ./QGroundcontrol 2>&1 | grep -E "ssl|crypto"

From this I could see that Qt finds openssl on the system.

Now, I still don't know how I can tell Qt to look somewhere else (in case I want to link another openssl), but that's another question.

Upvotes: 1

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