How to profile a specfic code section in C++ code using ncu/CUPTI

Question

currently I have a C++ source code src.cpp:

#include <Library.h> // This is a GPU library based on CUDA

    // All 3 function invoke CUDA kernels
    // While I don't know the exactly mapping between function and CUDA kernels
    Library::func1();
    Library::func2();
    Library::func3();

Now I only want to profile the CUDA kernel invoked by func3(), and ignore the kernels invoked by other functions. How can I do that?

It should be noted that src.cpp is purely C++ and is compiled using gcc, not nvcc.