Error ....undefined reference to `operator delete...QT 5.15.2

[Anonymous_Banned275]

Could anybody help me to get started in finding this error ?

I have a mutiproject project and I think I need to identify which project is actually using the
libQt5Qml.so. library.

Would that be a good starting point ?

For info - I get similar error irregardless which kit I use to compile.
I was going to build a separate btscanner (example) project to see if the error persist.
It seems odd that library would not be build with such common operator as "operator delete ".

make[1]: Nothing to be done for 'first'.
make[1]: Leaving directory '/mnt/da659056-4bac-42bc-a335-54f4a3167ed0/MDI_WORK_COPY_FOLDER/MDI_BT_Nov_15/MDI_BT/MDI_BT/SUB_FT857'
make[1]: Entering directory '/mnt/da659056-4bac-42bc-a335-54f4a3167ed0/MDI_WORK_COPY_FOLDER/MDI_BT_Nov_15/MDI_BT/MDI_BT/WebSDR'
make[1]: Nothing to be done for 'first'.
make[1]: Leaving directory '/mnt/da659056-4bac-42bc-a335-54f4a3167ed0/MDI_WORK_COPY_FOLDER/MDI_BT_Nov_15/MDI_BT/MDI_BT/WebSDR'
/usr/bin/ld: /home/q1/Qt/5.15.2/gcc_64/lib/libQt5Qml.so.5: undefined reference to operator delete[](void*, unsigned long)@Qt_5' /usr/bin/ld: /mnt/da659056-4bac-42bc-a335-54f4a3167ed0/MDI_WORK_COPY_FOLDER/MDI_BT_Nov_15/SOURCE/mdi/../bluetooth/btscanner//libbtscanner.so: undefined reference to operator delete(void*, unsigned long)@Qt_5'
collect2: error: ld returned 1 exit status
make[1]: Leaving directory '/mnt/da659056-4bac-42bc-a335-54f4a3167ed0/MDI_WORK_COPY_FOLDER/MDI_BT_Nov_15/SOURCE/mdi'
make[1]: *** [Makefile:369: mdi] Error 1
make: *** [Makefile:216: sub-------SOURCE-mdi-make_first] Error 2
21:46:36: The process "/usr/bin/make" exited with code 2.
Error while building/deploying project MDI_BT (kit: Replacement for "Desktop")
When executing step "Make"
21:46:36: Elapsed time: 00:16.

[J.Hilk]

@AnneRanch pass -lstdc++ to your linker call

[Anonymous_Banned275]

@J-Hilk said in Error ....undefined reference to `operator delete...QT 5.15.2:

pass -lstdc++ to your linker call

OK, I looked at this

https://doc.qt.io/qtcreator/creator-cli.html

That tells me I can add linker options to QTCreator command line.

I do not get why I have to use command line and not compiler / linker option line gcc

Also why this cannot be done in QT configuration ?

Of course the final question - why do I have to do this at all ?

I did build btscanner example and have no issues with this library, it does no seem to be used at all in btscanner example.
I have not seen this error in past , so why all of the sudden I get this error , especially when my subdir program does not use btscanner at the moment.

I am sorry to ask all this, but I am really concerned HOW to initially setup QT when I
a. load new OS - Ubuntu
b. install QT

It seems , to me, there are no comprehensive instructions how to do this initial setup.
It is all "hit and miss" ....

[Anonymous_Banned275]

@AnneRanch ABANDONED
I have found another full copy of my project.
Without any modification - using same kit and same version of Ubuntu - it compiles and run .
I am loosing patience to troubleshoot tools looking for weird failures like this one, I like to spent my time doing constructive work and I need to continue building my project.
However, I do appreciate the forum replies...
Cheers