CODEWITHSUNDEEP
c++11c++14
Maik Klein
Maik Klein

Reputation: 16148

Is it possible to include a type `T`'s string expansion into the error message given by `static_assert`?

This is a follow up questions from How to convert typename T to string in c++

I am asking because I would really like to generate nice error messages like

static_assert(one_of<T,Components...>::value,
              "Unable to access T because you didn't 
              use it in filter<Components...>.");

Would print

Unable to access Foo because you did not use it in filter<Bar,Baz,Bat>.

Is something like this now possible in C++11 / 14?

Upvotes: 2

Views: 107

Answers (2)

Pradhan
Pradhan

Reputation: 16777

Quoting from the poor(lazy?) man's version of the C++ Standard,

Since message(the second argument to static_assert) has to be a string literal, it cannot contain dynamic information or even a constant expression that is not a string literal itself. Typically, it cannot contain the name of the template type argument.

So, there isn't a way of getting the friendly static_assert error messages you desire.

Upvotes: 1

Puppy
Puppy

Reputation: 146988

No, no it is not possible to do that.

Upvotes: 0

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