How much overhead is there in calling a function in C++?

Question

A lot of literature talks about using inline functions to \"avoid the overhead of a function call\". However I haven\'t seen quantifiable data. What is the actual overhead o

Answer 1

There are a few issues here.

• If you have a smart enough compiler, it will do some automatic inlining for you even if you did not specify inline. On the other hand, there are many things that cannot be inlined.

• If the function is virtual, then of course you are going to pay the price that it cannot be inlined because the target is determined at runtime. Conversely, in Java, you might be paying this price unless you indicate that the method is final.

• Depending on how your code is organized in memory, you may be paying a cost in cache misses and even page misses as the code is located elsewhere. That can end up having a huge impact in some applications.