How to combine static_assert with sizeof and stringify?

Question

Memory usage is quite critical in my application. Therefore I have specific asserts that check for the memory size at compile time and give a static_assert if the size is d

Answer 1

I'd use dispatching on a function template to do the checking:

#include 

template 
void check_size() {
  static_assert(ExpectedSize == RealSize, "Size is off!");
}

struct foo
{
  char bla[16];
};

int main()
{
  check_size();
  return 0;
}

Results in:

In instantiation of ‘void check_size() [with ToCheck = foo; long unsigned int ExpectedSize = 8ul; long unsigned int RealSize = 16ul]’:
bla.cpp:15:22:   required from here
bla.cpp:5:1: error: static assertion failed: Size is off!

The debugging information is in the template parameters of the back-trace.

If this is truly better, you will have to decide and it also depends on the compiler. It also enables you to hide the expected size with a template map, to sum up to a max size and other fancy things.