NFD » ndn-cxx

The explicit specialization of DummyClientFace::receive for lp::Nack appears only in dummy-client-face.cpp. Users of the class will presumably include the corresponding header file instead, which does not declare any explicit specializations for the function template, thus the compiler will implicitly instantiate the "generic" version. This invokes undefined behavior according to the ISO C++ standard (§14.7.3):

If a template, a member template or a member of a class template is explicitly specialized then that specialization
shall be declared before the first use of that specialization that would cause an implicit instantiation
to take place, in every translation unit in which such a use occurs; no diagnostic is required.