C ++编译器不喜欢“使用INLINE = extern内联”

Question

There is a lot of information out there on the use of inline and how to properly do so for the desired intent such as here (which I am currently using as a reference) Inline Functions in C .

When I attempt to implement what is speficied in the page I get compiler errors for

using INLINE = extern inline;

and even just

using INLINE = extern;

The compiler says "expected type specifier before extern"

What I'm wondering is why can I use using this way?

Is it because using is really just reserved for types and substitutions?

Post Answer

Thank you so much! I totally missed the fact that I was reading through C reference. This is good news as it didn't seem like there was a really good way to deal with things from what I was reading but it is probably that way as it is out of date compared to what they are doing in C++11 now.

Answer 1

Is it because using is really just reserved for types and substitutions?

I don't know what you mean by substitutions, but yes to the reservation for types. An alias declaration is for declaring new names for types . A pair of specifiers doesn't form a type. You can't even make it work by superficially adding a type name there, since the extern and inline specifiers only apply to object and function identifiers, and not their associated type.

The article uses a macro ( #define ) because token substitution is the only way to create user defined specifiers like you want to do.

It's also worth noting that in C++ inline and extern inline are the same thing. It's only in C (a different language to C++, and the subject of the linked article) that inline doesn't imply linkage, requiring you to specify extern .