Installing different QT versions from Maintenance tool

asterlo

After installing QT on debian derivative linux via the Maintenance tool, if I pop over to the directory that the qt is installed to and issue qmake I get an error that says this:

./qmake: symbol lookup error: ./qmake: undefined symbol: _ZN7QString6assignE14QAnyStringView, version Qt_6

That error is with version 6.7.3.

With version 6.6.3 this pops up:

./qmake: symbol lookup error: ./qmake: undefined symbol: _ZTVNSt3pmr25monotonic_buffer_resourceE, version Qt_6

The system version of qmake6 works as expected.

SGaist

So the answer is yes and it's what is affecting you right now.
Setting it makes the library loader lookup these folder first so that's why you get the wrong library loaded when calling qmake.
Its content is a bit surprising because it's the usual places where libraries are looked for by default.
My recommendation: put its definition in comment so it's not defined anymore.

SGaist

Hi and welcome to devnet,

Do you, by any chances, have LD_LIBRARY_PATH set ?

asterlo

@SGaist said in Installing different QT versions from Maintenance tool:

LD_LIBRARY_PATH

It definitely shows output:

echo $LD_LIBRARY_PATH
/usr/lib:/usr/local/lib:/usr/local/lib64:/usr/lib/x86_64-linux-gnu

Not sure if that's a yes in terms of your question, though.

SGaist

So the answer is yes and it's what is affecting you right now.
Setting it makes the library loader lookup these folder first so that's why you get the wrong library loaded when calling qmake.
Its content is a bit surprising because it's the usual places where libraries are looked for by default.
My recommendation: put its definition in comment so it's not defined anymore.

asterlo

@SGaist

Yep, this was right. I didn't realize LD path was the forerunner that would take precedence in the command path of a given directory.

I had to type this command to figure out what was setting LD_LIBRARY_PATH since the standard advice of editing a .conf file in etc had no affect:

grep LD_LIBRARY_PATH= ~/.* /etc/*

I found that useful info here: https://askubuntu.com/questions/233943/how-can-i-re-order-ld-library-path

In my system it turned out that ./.bashrc was setting this info, so I commented it out and then opened a new command prompt and the problem was solved. (after sourcing ./.bashrc)

Thanks for the insight!

SGaist

You're welcome !

Since you have it working now, please mark the thread as solved using the "Topic Tools" button or the three dotted menu beside the answer you deem correct so that other forum users may know a solution has been found :-)