Sizeof of std::function type

Question

What kind of magic does the std::function from C++11 that its sizeof = 32? If I\'d store the function reference as a pointer, it\

Answer 1

std::function is indeed magic, as it can be constructed from any callable object! It will happily store any amount of state for you, even if on the surface you retain a measly void(int&) signature.

There's certainly a price attached to this magic, which typically uses some sort of type erasure (i.e. a dynamic allocation and virtual dispatch) internally. The details vary, but the resulting objects are certainly "heavy" — which is why they should be avoided in favour of auto and templates whenever feasible!