Are there any cases where it is incorrect to replace push_back with emplace_back?

Question

Can I break a valid C++03 program by replacing std::vector::push_back with emplace_back and compiling it with C++ 11 compiler? From reading e

Answer 1

int main() {
std::vector().push_back(0);
std::vector().emplace_back(0); 
}

Give struct constructor in emplace_back i.e The above code will be like this

int main() {
std::vector().push_back(0); 
std::vector().emplace_back(S(0)); 
}