This results in compiler warnings such as this:

In file included from /Users/phil/Code/noaa/ngen/extern/test_bmi_cpp/src/test_bmi_cpp.cpp:6:
/Users/phil/Code/noaa/ngen/extern/test_bmi_cpp/include/test_bmi_cpp.hpp: In function 'void bmi_model_destroy(TestBmiCpp*)':
/Users/phil/Code/noaa/ngen/extern/test_bmi_cpp/include/test_bmi_cpp.hpp:275:17: warning: deleting object of polymorphic class type 'TestBmiCpp' which has non-virtual destructor might cause undefined behavior [-Wdelete-non-virtual-dtor]
  275 |                 delete ptr;

@aufdenkampe Have you run into this issue in your work BMI-ing C++ models? Note that @PhilMiller provides a fix in #12.

@mdpiper, I think merging PR #12 from @PhilMiller makes sense to me.

Although our team still haven't gotten far enough along with our BMI C++ work to have encountered an issue with not having a virtual destructor method, from my work with embedded C++ (in https://github.com/EnviroDIY/ModularSensors), I know that adding an virtual destructor method to every class is important, to be able to clear an instantiated object from memory. The syntax that @PhilMiller suggested is exactly the way we implement destructors in our code.

@aufdenkampe Thank you for your comment on this. I'll try to get things moving in the PR.