If you have linker problems you might want to ensure that you actually have the librariess that you are linking into your program on your ld search path. This can be investigated using ldconfig and grep
ldconfig -v
prints out the paths on the ld search path and what libraries is on the path.
It might be a gooe idea to redirect stderr to /dev/null like
ldconfig -v 2>/dev/null
And if you are looking for a specific library then use grep (with -i for “ignore-case”) eg:
ldconfig -v 2>/dev/null | grep -i qtgui
Tags: case insensitive, grep, ldconfig, shared library