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's the technical and the practical answer. The practical answer is it will never matter, and in the very rare case it does the only way you'll know is through actual profiled tests.

The technical answer, which your literature refers to, is generally not relevant due to compiler optimizations. But if you're still interested, is well described by Josh.

As far as a "percentage" you'd have to know how expensive the function itself was. Outside of the cost of the called function there is no percentage because you are comparing to a zero cost operation. For inlined code there is no cost, the processor just moves to the next instruction. The downside to inling is a larger code size which manifests it's costs in a different way than the stack construction/tear down costs.