User-defined attributes in C++11?

Question

Is there a way to create user-defined attributes in C++11 or later?

For example,

[[noreturn]] void exit();

is a compiler-defined C++11 attribute.

I'd like to define something like:

[[comingsoon]] int function(int);

Is there a mechanism for this?

Edit: I should mention I'm using Clang.

Answer 1

For now it's not possible to define user-attributes.

There is, as far as i know, no information about if this feature is planned or not. However, look at this FAQ answer from Stroustrup : https://isocpp.org/wiki/faq/cpp11-language-misc#attributes, especially this part :

One planned use for attributes is improved support for OpenMP. For example:

for [ [ omp::parallel() ] ] (int i=0; i<v.size(); ++i) {
    // ...
}

It could mean that they plan to allow programmer to define it's own attribute. Wait & see.

Answer 2

The language provides no way of adding attributes.

Of course, if you are using Clang, you can edit the source of Clang, and add any attributes you like.