static vs inline for functions implemented in header files

Question

The way I think of inline in C++ is for linkage/scoping. I put it in the same basket with extern and static for global objects.

Ty

Answer 1

In many cases you will not notice a difference because compilers and linkers are pretty smart these days. However, an inline function must behave as-if it was a regular function. A static function in a header will get compiled into every source file which includes it - so there will be lots of copies of it.

Mostly, this doesn't matter much, but there are a few ways it does. An inline function has one address. Static functions will have a different address in each translation unit.

Static-local variables: WIth the inline, there will be a single copy of them. With static-functions, there will be a unique copy of each static-local variable for each translation unit that includes that function.