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

7.1.2 Function specifiers

A function declaration (8.3.5, 9.3, 11.4) with an inline specifier declares an inline function. The inline specifier indicates to the implementation that inline substitution of the function body at the point of call is to be preferred to the usual function call mechanism. An implementation is not required to perform this inline substitution at the point of call; however, even if this inline substitution is omitted, the other rules for inline functions defined by 7.1.2 shall still be respected.

So, the compiler is not required to actually 'inline' any function.

However, the standard also says,

An inline function with external linkage shall have the same address in all translation units.

Member functions normally have external linkage (one exception is when the member function belongs to a 'local' class), so inline functions must have a unique address for cases where the address of the function is taken. In this case, the compiler will arrange for the linker to throw away all but one instance of a non-inlined copy of the function and fix-up all address references to the function to be to the one that's kept.