Print template typename at compile time

Question

When creating a template function in C++ is there a simple way to have the typename of the template represented as a string? I have a simple test case to show what I\'m try

Answer 1

To get a useful compile time name:

Supposing you have some unknown type named 'T'. You can get the compiler to print it's type by using it horribly. For example:

typedef typename T::something_made_up X;

The error message will be like:

error: no type named 'something_made_up' in 'Wt::Dbo::ptr'

The bit after 'in' shows the type. (Only tested with clang).

Other ways of triggering it:

bool x = T::nothing;   // error: no member named 'nothing' in 'Wt::Dbo::ptr'
using X = typename T::nothing;  // error: no type named 'nothing' in 'Wt::Dbo::ptr'

With C++11, you may already have an object and use 'decltype' to get its type, so you can also run:

auto obj = creatSomeObject();
bool x = decltype(obj)::nothing; // (Where nothing is not a real member).