How to do static_assert with macros?

Question

I have tried to use this suggestion to do a static assert, but I do not get a compilation error if I use it within a method of a template.

The example follows :

Answer 1

int foo(const int k)
{
  STATIC_ASSERT( k > 9, error_msg );
  return k+5;
}

Static assertions only work with compile-time constant expressions.

k is not a compile-time constant expression.

Non-type template parameters are compile-time constant expressions during template instantiation, so you could adapt your code thus:

template 
int foo()
{
  STATIC_ASSERT( K > 9, error_msg );
  return K+5;
}