How do I add physical procedures to a DICOM instance

Hi geant4ers
I recently wanted to add my own physical procedures to the DICOM example, so I wrote the physicslist. hh and Physicslist. cc files.But I started reporting errors when I used my own physical procedure in main().At first I thought there was something wrong with my program, but when I copied the physical process directly from the example RadioactiveDecay, I got the same error. The error message is as follows:

/usr/bin/ld: CMakeFiles/DICOM.dir/ o: in function main': undefined reference to PhysicsList::PhysicsList()’
collect2: error: ld returned 1 exit status
make[2]: *** [CMakeFiles/DICOM.dir/build. make:132:DICOM] error 1
make[1]: *** [CMakeFiles/Makefile2:78:CMakeFiles/DICOM. dir/all] error 2
make: *** [Makefile:130:all] error 2

As a newcomer, I really don’t know what to do, so I’d like to ask for a little help.I sincerely look forward to your reply, which will be of great help to me.