Are C++ class methods defined in the header always inlined?

Question

Edit: I\'ve restored the original title but really what I should have asked was this: \'How do C++ linkers handle class methods which have be

Answer 1

There is no - single answer to this question. Compilers are smart beasts. You can specifically use the inline words if you want, but this doesn't mean that the compiler will actually inline the function.

Inline is there to help the developer with optmization. It hints at the compiler that something should be inlined, but these hints are generally ignored nowadays, since compilers can do better at register assignment and deciding when to inline functions (in fact, a compiler can either inline or not inline a function at different times). Code generation on modern processors is far more complicated than on the more deterministic ones common when Ritchie was inventing C.

What the word means now, in C++, is that it can have multiple identical definitions, and needs to be defined in every translation unit that uses it. (In other words, you need to make sure it can be inlined.) You can have an inline function in a header with no problems, and member functions defined in a class definition are automatically effectively inline.

That said, I used to work with a greenhills compiler, and it actually obeyed my will more than it disobeyed it :).. It's up to the compiler, really.