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Virtual Functions and Performance C++
Is this correct, that class member function takes more time than a simple function? What if inheritance and virtual functions are used?
I have tried to collect my functions into a simple interface class (only member functions, no data members), and it appears that I lose time. Is there a way to fix it?
P.S. I’m checking with gcc and icc compilers and using -O3 option.
Premature optimization is the root of all evil
A nonstatic member function takes an additional argument, which is the object (a pointer or reference to it) on which the function is called. This is one overhead. If the function is virtual, then there is also one small indirection in case of a polymorphic call, that is, addition of the function index to the virtual table base offset. Both of these "overheads" are sooo negligable, you shouldn’t worry about it unless the profiler says this is your bottleneck. Which it most likely is not.
Premature optimization is the root of all evil